LCOV - code coverage report
Current view: top level - kernel/cgroup - cpuset.c (source / functions) Hit Total Coverage
Test: combined.info Lines: 80 1256 6.4 %
Date: 2022-03-28 13:20:08 Functions: 12 75 16.0 %
Branches: 17 889 1.9 %

           Branch data     Line data    Source code
       1                 :            : /*
       2                 :            :  *  kernel/cpuset.c
       3                 :            :  *
       4                 :            :  *  Processor and Memory placement constraints for sets of tasks.
       5                 :            :  *
       6                 :            :  *  Copyright (C) 2003 BULL SA.
       7                 :            :  *  Copyright (C) 2004-2007 Silicon Graphics, Inc.
       8                 :            :  *  Copyright (C) 2006 Google, Inc
       9                 :            :  *
      10                 :            :  *  Portions derived from Patrick Mochel's sysfs code.
      11                 :            :  *  sysfs is Copyright (c) 2001-3 Patrick Mochel
      12                 :            :  *
      13                 :            :  *  2003-10-10 Written by Simon Derr.
      14                 :            :  *  2003-10-22 Updates by Stephen Hemminger.
      15                 :            :  *  2004 May-July Rework by Paul Jackson.
      16                 :            :  *  2006 Rework by Paul Menage to use generic cgroups
      17                 :            :  *  2008 Rework of the scheduler domains and CPU hotplug handling
      18                 :            :  *       by Max Krasnyansky
      19                 :            :  *
      20                 :            :  *  This file is subject to the terms and conditions of the GNU General Public
      21                 :            :  *  License.  See the file COPYING in the main directory of the Linux
      22                 :            :  *  distribution for more details.
      23                 :            :  */
      24                 :            : 
      25                 :            : #include <linux/cpu.h>
      26                 :            : #include <linux/cpumask.h>
      27                 :            : #include <linux/cpuset.h>
      28                 :            : #include <linux/err.h>
      29                 :            : #include <linux/errno.h>
      30                 :            : #include <linux/file.h>
      31                 :            : #include <linux/fs.h>
      32                 :            : #include <linux/init.h>
      33                 :            : #include <linux/interrupt.h>
      34                 :            : #include <linux/kernel.h>
      35                 :            : #include <linux/kmod.h>
      36                 :            : #include <linux/list.h>
      37                 :            : #include <linux/mempolicy.h>
      38                 :            : #include <linux/mm.h>
      39                 :            : #include <linux/memory.h>
      40                 :            : #include <linux/export.h>
      41                 :            : #include <linux/mount.h>
      42                 :            : #include <linux/fs_context.h>
      43                 :            : #include <linux/namei.h>
      44                 :            : #include <linux/pagemap.h>
      45                 :            : #include <linux/proc_fs.h>
      46                 :            : #include <linux/rcupdate.h>
      47                 :            : #include <linux/sched.h>
      48                 :            : #include <linux/sched/deadline.h>
      49                 :            : #include <linux/sched/mm.h>
      50                 :            : #include <linux/sched/task.h>
      51                 :            : #include <linux/seq_file.h>
      52                 :            : #include <linux/security.h>
      53                 :            : #include <linux/slab.h>
      54                 :            : #include <linux/spinlock.h>
      55                 :            : #include <linux/stat.h>
      56                 :            : #include <linux/string.h>
      57                 :            : #include <linux/time.h>
      58                 :            : #include <linux/time64.h>
      59                 :            : #include <linux/backing-dev.h>
      60                 :            : #include <linux/sort.h>
      61                 :            : #include <linux/oom.h>
      62                 :            : #include <linux/sched/isolation.h>
      63                 :            : #include <linux/uaccess.h>
      64                 :            : #include <linux/atomic.h>
      65                 :            : #include <linux/mutex.h>
      66                 :            : #include <linux/cgroup.h>
      67                 :            : #include <linux/wait.h>
      68                 :            : 
      69                 :            : DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key);
      70                 :            : DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
      71                 :            : 
      72                 :            : /* See "Frequency meter" comments, below. */
      73                 :            : 
      74                 :            : struct fmeter {
      75                 :            :         int cnt;                /* unprocessed events count */
      76                 :            :         int val;                /* most recent output value */
      77                 :            :         time64_t time;          /* clock (secs) when val computed */
      78                 :            :         spinlock_t lock;        /* guards read or write of above */
      79                 :            : };
      80                 :            : 
      81                 :            : struct cpuset {
      82                 :            :         struct cgroup_subsys_state css;
      83                 :            : 
      84                 :            :         unsigned long flags;            /* "unsigned long" so bitops work */
      85                 :            : 
      86                 :            :         /*
      87                 :            :          * On default hierarchy:
      88                 :            :          *
      89                 :            :          * The user-configured masks can only be changed by writing to
      90                 :            :          * cpuset.cpus and cpuset.mems, and won't be limited by the
      91                 :            :          * parent masks.
      92                 :            :          *
      93                 :            :          * The effective masks is the real masks that apply to the tasks
      94                 :            :          * in the cpuset. They may be changed if the configured masks are
      95                 :            :          * changed or hotplug happens.
      96                 :            :          *
      97                 :            :          * effective_mask == configured_mask & parent's effective_mask,
      98                 :            :          * and if it ends up empty, it will inherit the parent's mask.
      99                 :            :          *
     100                 :            :          *
     101                 :            :          * On legacy hierachy:
     102                 :            :          *
     103                 :            :          * The user-configured masks are always the same with effective masks.
     104                 :            :          */
     105                 :            : 
     106                 :            :         /* user-configured CPUs and Memory Nodes allow to tasks */
     107                 :            :         cpumask_var_t cpus_allowed;
     108                 :            :         nodemask_t mems_allowed;
     109                 :            : 
     110                 :            :         /* effective CPUs and Memory Nodes allow to tasks */
     111                 :            :         cpumask_var_t effective_cpus;
     112                 :            :         nodemask_t effective_mems;
     113                 :            : 
     114                 :            :         /*
     115                 :            :          * CPUs allocated to child sub-partitions (default hierarchy only)
     116                 :            :          * - CPUs granted by the parent = effective_cpus U subparts_cpus
     117                 :            :          * - effective_cpus and subparts_cpus are mutually exclusive.
     118                 :            :          *
     119                 :            :          * effective_cpus contains only onlined CPUs, but subparts_cpus
     120                 :            :          * may have offlined ones.
     121                 :            :          */
     122                 :            :         cpumask_var_t subparts_cpus;
     123                 :            : 
     124                 :            :         /*
     125                 :            :          * This is old Memory Nodes tasks took on.
     126                 :            :          *
     127                 :            :          * - top_cpuset.old_mems_allowed is initialized to mems_allowed.
     128                 :            :          * - A new cpuset's old_mems_allowed is initialized when some
     129                 :            :          *   task is moved into it.
     130                 :            :          * - old_mems_allowed is used in cpuset_migrate_mm() when we change
     131                 :            :          *   cpuset.mems_allowed and have tasks' nodemask updated, and
     132                 :            :          *   then old_mems_allowed is updated to mems_allowed.
     133                 :            :          */
     134                 :            :         nodemask_t old_mems_allowed;
     135                 :            : 
     136                 :            :         struct fmeter fmeter;           /* memory_pressure filter */
     137                 :            : 
     138                 :            :         /*
     139                 :            :          * Tasks are being attached to this cpuset.  Used to prevent
     140                 :            :          * zeroing cpus/mems_allowed between ->can_attach() and ->attach().
     141                 :            :          */
     142                 :            :         int attach_in_progress;
     143                 :            : 
     144                 :            :         /* partition number for rebuild_sched_domains() */
     145                 :            :         int pn;
     146                 :            : 
     147                 :            :         /* for custom sched domain */
     148                 :            :         int relax_domain_level;
     149                 :            : 
     150                 :            :         /* number of CPUs in subparts_cpus */
     151                 :            :         int nr_subparts_cpus;
     152                 :            : 
     153                 :            :         /* partition root state */
     154                 :            :         int partition_root_state;
     155                 :            : 
     156                 :            :         /*
     157                 :            :          * Default hierarchy only:
     158                 :            :          * use_parent_ecpus - set if using parent's effective_cpus
     159                 :            :          * child_ecpus_count - # of children with use_parent_ecpus set
     160                 :            :          */
     161                 :            :         int use_parent_ecpus;
     162                 :            :         int child_ecpus_count;
     163                 :            : };
     164                 :            : 
     165                 :            : /*
     166                 :            :  * Partition root states:
     167                 :            :  *
     168                 :            :  *   0 - not a partition root
     169                 :            :  *
     170                 :            :  *   1 - partition root
     171                 :            :  *
     172                 :            :  *  -1 - invalid partition root
     173                 :            :  *       None of the cpus in cpus_allowed can be put into the parent's
     174                 :            :  *       subparts_cpus. In this case, the cpuset is not a real partition
     175                 :            :  *       root anymore.  However, the CPU_EXCLUSIVE bit will still be set
     176                 :            :  *       and the cpuset can be restored back to a partition root if the
     177                 :            :  *       parent cpuset can give more CPUs back to this child cpuset.
     178                 :            :  */
     179                 :            : #define PRS_DISABLED            0
     180                 :            : #define PRS_ENABLED             1
     181                 :            : #define PRS_ERROR               -1
     182                 :            : 
     183                 :            : /*
     184                 :            :  * Temporary cpumasks for working with partitions that are passed among
     185                 :            :  * functions to avoid memory allocation in inner functions.
     186                 :            :  */
     187                 :            : struct tmpmasks {
     188                 :            :         cpumask_var_t addmask, delmask; /* For partition root */
     189                 :            :         cpumask_var_t new_cpus;         /* For update_cpumasks_hier() */
     190                 :            : };
     191                 :            : 
     192                 :         90 : static inline struct cpuset *css_cs(struct cgroup_subsys_state *css)
     193                 :            : {
     194   [ -  -  -  -  :         30 :         return css ? container_of(css, struct cpuset, css) : NULL;
          -  -  -  -  -  
          -  -  -  -  -  
          -  -  -  -  -  
             -  -  -  -  
                      + ]
     195                 :            : }
     196                 :            : 
     197                 :            : /* Retrieve the cpuset for a task */
     198                 :         30 : static inline struct cpuset *task_cs(struct task_struct *task)
     199                 :            : {
     200   [ -  -  -  -  :         30 :         return css_cs(task_css(task, cpuset_cgrp_id));
          -  -  -  -  -  
                -  -  + ]
     201                 :            : }
     202                 :            : 
     203                 :         30 : static inline struct cpuset *parent_cs(struct cpuset *cs)
     204                 :            : {
     205                 :         30 :         return css_cs(cs->css.parent);
     206                 :            : }
     207                 :            : 
     208                 :            : /* bits in struct cpuset flags field */
     209                 :            : typedef enum {
     210                 :            :         CS_ONLINE,
     211                 :            :         CS_CPU_EXCLUSIVE,
     212                 :            :         CS_MEM_EXCLUSIVE,
     213                 :            :         CS_MEM_HARDWALL,
     214                 :            :         CS_MEMORY_MIGRATE,
     215                 :            :         CS_SCHED_LOAD_BALANCE,
     216                 :            :         CS_SPREAD_PAGE,
     217                 :            :         CS_SPREAD_SLAB,
     218                 :            : } cpuset_flagbits_t;
     219                 :            : 
     220                 :            : /* convenient tests for these bits */
     221                 :          0 : static inline bool is_cpuset_online(struct cpuset *cs)
     222                 :            : {
     223   [ #  #  #  # ]:          0 :         return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css);
     224                 :            : }
     225                 :            : 
     226                 :          0 : static inline int is_cpu_exclusive(const struct cpuset *cs)
     227                 :            : {
     228                 :          0 :         return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
     229                 :            : }
     230                 :            : 
     231                 :          0 : static inline int is_mem_exclusive(const struct cpuset *cs)
     232                 :            : {
     233                 :          0 :         return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
     234                 :            : }
     235                 :            : 
     236                 :          0 : static inline int is_mem_hardwall(const struct cpuset *cs)
     237                 :            : {
     238                 :          0 :         return test_bit(CS_MEM_HARDWALL, &cs->flags);
     239                 :            : }
     240                 :            : 
     241                 :          0 : static inline int is_sched_load_balance(const struct cpuset *cs)
     242                 :            : {
     243                 :          0 :         return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
     244                 :            : }
     245                 :            : 
     246                 :          0 : static inline int is_memory_migrate(const struct cpuset *cs)
     247                 :            : {
     248                 :          0 :         return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
     249                 :            : }
     250                 :            : 
     251                 :          0 : static inline int is_spread_page(const struct cpuset *cs)
     252                 :            : {
     253                 :          0 :         return test_bit(CS_SPREAD_PAGE, &cs->flags);
     254                 :            : }
     255                 :            : 
     256                 :          0 : static inline int is_spread_slab(const struct cpuset *cs)
     257                 :            : {
     258                 :          0 :         return test_bit(CS_SPREAD_SLAB, &cs->flags);
     259                 :            : }
     260                 :            : 
     261                 :          0 : static inline int is_partition_root(const struct cpuset *cs)
     262                 :            : {
     263                 :          0 :         return cs->partition_root_state > 0;
     264                 :            : }
     265                 :            : 
     266                 :            : static struct cpuset top_cpuset = {
     267                 :            :         .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
     268                 :            :                   (1 << CS_MEM_EXCLUSIVE)),
     269                 :            :         .partition_root_state = PRS_ENABLED,
     270                 :            : };
     271                 :            : 
     272                 :            : /**
     273                 :            :  * cpuset_for_each_child - traverse online children of a cpuset
     274                 :            :  * @child_cs: loop cursor pointing to the current child
     275                 :            :  * @pos_css: used for iteration
     276                 :            :  * @parent_cs: target cpuset to walk children of
     277                 :            :  *
     278                 :            :  * Walk @child_cs through the online children of @parent_cs.  Must be used
     279                 :            :  * with RCU read locked.
     280                 :            :  */
     281                 :            : #define cpuset_for_each_child(child_cs, pos_css, parent_cs)             \
     282                 :            :         css_for_each_child((pos_css), &(parent_cs)->css)         \
     283                 :            :                 if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
     284                 :            : 
     285                 :            : /**
     286                 :            :  * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
     287                 :            :  * @des_cs: loop cursor pointing to the current descendant
     288                 :            :  * @pos_css: used for iteration
     289                 :            :  * @root_cs: target cpuset to walk ancestor of
     290                 :            :  *
     291                 :            :  * Walk @des_cs through the online descendants of @root_cs.  Must be used
     292                 :            :  * with RCU read locked.  The caller may modify @pos_css by calling
     293                 :            :  * css_rightmost_descendant() to skip subtree.  @root_cs is included in the
     294                 :            :  * iteration and the first node to be visited.
     295                 :            :  */
     296                 :            : #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs)        \
     297                 :            :         css_for_each_descendant_pre((pos_css), &(root_cs)->css)          \
     298                 :            :                 if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
     299                 :            : 
     300                 :            : /*
     301                 :            :  * There are two global locks guarding cpuset structures - cpuset_mutex and
     302                 :            :  * callback_lock. We also require taking task_lock() when dereferencing a
     303                 :            :  * task's cpuset pointer. See "The task_lock() exception", at the end of this
     304                 :            :  * comment.
     305                 :            :  *
     306                 :            :  * A task must hold both locks to modify cpusets.  If a task holds
     307                 :            :  * cpuset_mutex, then it blocks others wanting that mutex, ensuring that it
     308                 :            :  * is the only task able to also acquire callback_lock and be able to
     309                 :            :  * modify cpusets.  It can perform various checks on the cpuset structure
     310                 :            :  * first, knowing nothing will change.  It can also allocate memory while
     311                 :            :  * just holding cpuset_mutex.  While it is performing these checks, various
     312                 :            :  * callback routines can briefly acquire callback_lock to query cpusets.
     313                 :            :  * Once it is ready to make the changes, it takes callback_lock, blocking
     314                 :            :  * everyone else.
     315                 :            :  *
     316                 :            :  * Calls to the kernel memory allocator can not be made while holding
     317                 :            :  * callback_lock, as that would risk double tripping on callback_lock
     318                 :            :  * from one of the callbacks into the cpuset code from within
     319                 :            :  * __alloc_pages().
     320                 :            :  *
     321                 :            :  * If a task is only holding callback_lock, then it has read-only
     322                 :            :  * access to cpusets.
     323                 :            :  *
     324                 :            :  * Now, the task_struct fields mems_allowed and mempolicy may be changed
     325                 :            :  * by other task, we use alloc_lock in the task_struct fields to protect
     326                 :            :  * them.
     327                 :            :  *
     328                 :            :  * The cpuset_common_file_read() handlers only hold callback_lock across
     329                 :            :  * small pieces of code, such as when reading out possibly multi-word
     330                 :            :  * cpumasks and nodemasks.
     331                 :            :  *
     332                 :            :  * Accessing a task's cpuset should be done in accordance with the
     333                 :            :  * guidelines for accessing subsystem state in kernel/cgroup.c
     334                 :            :  */
     335                 :            : 
     336                 :            : DEFINE_STATIC_PERCPU_RWSEM(cpuset_rwsem);
     337                 :            : 
     338                 :       2187 : void cpuset_read_lock(void)
     339                 :            : {
     340                 :       2187 :         percpu_down_read(&cpuset_rwsem);
     341                 :       2187 : }
     342                 :            : 
     343                 :       2187 : void cpuset_read_unlock(void)
     344                 :            : {
     345                 :       2187 :         percpu_up_read(&cpuset_rwsem);
     346                 :       2187 : }
     347                 :            : 
     348                 :            : static DEFINE_SPINLOCK(callback_lock);
     349                 :            : 
     350                 :            : static struct workqueue_struct *cpuset_migrate_mm_wq;
     351                 :            : 
     352                 :            : /*
     353                 :            :  * CPU / memory hotplug is handled asynchronously.
     354                 :            :  */
     355                 :            : static void cpuset_hotplug_workfn(struct work_struct *work);
     356                 :            : static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
     357                 :            : 
     358                 :            : static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
     359                 :            : 
     360                 :            : /*
     361                 :            :  * Cgroup v2 behavior is used when on default hierarchy or the
     362                 :            :  * cgroup_v2_mode flag is set.
     363                 :            :  */
     364                 :         60 : static inline bool is_in_v2_mode(void)
     365                 :            : {
     366   [ -  -  -  -  :         60 :         return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
          -  -  +  +  -  
          -  -  -  -  -  
          -  -  -  -  -  
                -  -  - ]
     367   [ -  -  -  -  :         30 :               (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
          -  -  +  -  -  
          -  -  -  -  -  
          -  -  -  -  -  
                -  -  - ]
     368                 :            : }
     369                 :            : 
     370                 :            : /*
     371                 :            :  * Return in pmask the portion of a cpusets's cpus_allowed that
     372                 :            :  * are online.  If none are online, walk up the cpuset hierarchy
     373                 :            :  * until we find one that does have some online cpus.
     374                 :            :  *
     375                 :            :  * One way or another, we guarantee to return some non-empty subset
     376                 :            :  * of cpu_online_mask.
     377                 :            :  *
     378                 :            :  * Call with callback_lock or cpuset_mutex held.
     379                 :            :  */
     380                 :            : static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask)
     381                 :            : {
     382   [ #  #  #  # ]:          0 :         while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) {
     383   [ #  #  #  # ]:          0 :                 cs = parent_cs(cs);
     384   [ #  #  #  # ]:          0 :                 if (unlikely(!cs)) {
     385                 :            :                         /*
     386                 :            :                          * The top cpuset doesn't have any online cpu as a
     387                 :            :                          * consequence of a race between cpuset_hotplug_work
     388                 :            :                          * and cpu hotplug notifier.  But we know the top
     389                 :            :                          * cpuset's effective_cpus is on its way to to be
     390                 :            :                          * identical to cpu_online_mask.
     391                 :            :                          */
     392                 :          0 :                         cpumask_copy(pmask, cpu_online_mask);
     393                 :          0 :                         return;
     394                 :            :                 }
     395                 :            :         }
     396                 :          0 :         cpumask_and(pmask, cs->effective_cpus, cpu_online_mask);
     397                 :            : }
     398                 :            : 
     399                 :            : /*
     400                 :            :  * Return in *pmask the portion of a cpusets's mems_allowed that
     401                 :            :  * are online, with memory.  If none are online with memory, walk
     402                 :            :  * up the cpuset hierarchy until we find one that does have some
     403                 :            :  * online mems.  The top cpuset always has some mems online.
     404                 :            :  *
     405                 :            :  * One way or another, we guarantee to return some non-empty subset
     406                 :            :  * of node_states[N_MEMORY].
     407                 :            :  *
     408                 :            :  * Call with callback_lock or cpuset_mutex held.
     409                 :            :  */
     410                 :          0 : static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
     411                 :            : {
     412         [ #  # ]:          0 :         while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY]))
     413         [ #  # ]:          0 :                 cs = parent_cs(cs);
     414                 :          0 :         nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);
     415                 :          0 : }
     416                 :            : 
     417                 :            : /*
     418                 :            :  * update task's spread flag if cpuset's page/slab spread flag is set
     419                 :            :  *
     420                 :            :  * Call with callback_lock or cpuset_mutex held.
     421                 :            :  */
     422                 :          0 : static void cpuset_update_task_spread_flag(struct cpuset *cs,
     423                 :            :                                         struct task_struct *tsk)
     424                 :            : {
     425         [ #  # ]:          0 :         if (is_spread_page(cs))
     426                 :          0 :                 task_set_spread_page(tsk);
     427                 :            :         else
     428                 :          0 :                 task_clear_spread_page(tsk);
     429                 :            : 
     430         [ #  # ]:          0 :         if (is_spread_slab(cs))
     431                 :          0 :                 task_set_spread_slab(tsk);
     432                 :            :         else
     433                 :          0 :                 task_clear_spread_slab(tsk);
     434                 :          0 : }
     435                 :            : 
     436                 :            : /*
     437                 :            :  * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
     438                 :            :  *
     439                 :            :  * One cpuset is a subset of another if all its allowed CPUs and
     440                 :            :  * Memory Nodes are a subset of the other, and its exclusive flags
     441                 :            :  * are only set if the other's are set.  Call holding cpuset_mutex.
     442                 :            :  */
     443                 :            : 
     444                 :          0 : static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
     445                 :            : {
     446   [ #  #  #  # ]:          0 :         return  cpumask_subset(p->cpus_allowed, q->cpus_allowed) &&
     447         [ #  # ]:          0 :                 nodes_subset(p->mems_allowed, q->mems_allowed) &&
     448   [ #  #  #  # ]:          0 :                 is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
     449                 :            :                 is_mem_exclusive(p) <= is_mem_exclusive(q);
     450                 :            : }
     451                 :            : 
     452                 :            : /**
     453                 :            :  * alloc_cpumasks - allocate three cpumasks for cpuset
     454                 :            :  * @cs:  the cpuset that have cpumasks to be allocated.
     455                 :            :  * @tmp: the tmpmasks structure pointer
     456                 :            :  * Return: 0 if successful, -ENOMEM otherwise.
     457                 :            :  *
     458                 :            :  * Only one of the two input arguments should be non-NULL.
     459                 :            :  */
     460                 :          0 : static inline int alloc_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
     461                 :            : {
     462                 :          0 :         cpumask_var_t *pmask1, *pmask2, *pmask3;
     463                 :            : 
     464         [ #  # ]:          0 :         if (cs) {
     465                 :          0 :                 pmask1 = &cs->cpus_allowed;
     466                 :          0 :                 pmask2 = &cs->effective_cpus;
     467                 :          0 :                 pmask3 = &cs->subparts_cpus;
     468                 :            :         } else {
     469                 :          0 :                 pmask1 = &tmp->new_cpus;
     470                 :          0 :                 pmask2 = &tmp->addmask;
     471                 :          0 :                 pmask3 = &tmp->delmask;
     472                 :            :         }
     473                 :            : 
     474                 :          0 :         if (!zalloc_cpumask_var(pmask1, GFP_KERNEL))
     475                 :            :                 return -ENOMEM;
     476                 :            : 
     477                 :          0 :         if (!zalloc_cpumask_var(pmask2, GFP_KERNEL))
     478                 :            :                 goto free_one;
     479                 :            : 
     480                 :          0 :         if (!zalloc_cpumask_var(pmask3, GFP_KERNEL))
     481                 :            :                 goto free_two;
     482                 :            : 
     483                 :          0 :         return 0;
     484                 :            : 
     485                 :            : free_two:
     486                 :            :         free_cpumask_var(*pmask2);
     487                 :            : free_one:
     488                 :            :         free_cpumask_var(*pmask1);
     489                 :            :         return -ENOMEM;
     490                 :            : }
     491                 :            : 
     492                 :            : /**
     493                 :            :  * free_cpumasks - free cpumasks in a tmpmasks structure
     494                 :            :  * @cs:  the cpuset that have cpumasks to be free.
     495                 :            :  * @tmp: the tmpmasks structure pointer
     496                 :            :  */
     497                 :          0 : static inline void free_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
     498                 :            : {
     499                 :          0 :         if (cs) {
     500                 :            :                 free_cpumask_var(cs->cpus_allowed);
     501                 :            :                 free_cpumask_var(cs->effective_cpus);
     502                 :            :                 free_cpumask_var(cs->subparts_cpus);
     503                 :            :         }
     504                 :          0 :         if (tmp) {
     505                 :            :                 free_cpumask_var(tmp->new_cpus);
     506                 :            :                 free_cpumask_var(tmp->addmask);
     507                 :            :                 free_cpumask_var(tmp->delmask);
     508                 :            :         }
     509                 :            : }
     510                 :            : 
     511                 :            : /**
     512                 :            :  * alloc_trial_cpuset - allocate a trial cpuset
     513                 :            :  * @cs: the cpuset that the trial cpuset duplicates
     514                 :            :  */
     515                 :          0 : static struct cpuset *alloc_trial_cpuset(struct cpuset *cs)
     516                 :            : {
     517                 :          0 :         struct cpuset *trial;
     518                 :            : 
     519                 :          0 :         trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
     520         [ #  # ]:          0 :         if (!trial)
     521                 :            :                 return NULL;
     522                 :            : 
     523         [ #  # ]:          0 :         if (alloc_cpumasks(trial, NULL)) {
     524                 :          0 :                 kfree(trial);
     525                 :          0 :                 return NULL;
     526                 :            :         }
     527                 :            : 
     528                 :          0 :         cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);
     529                 :          0 :         cpumask_copy(trial->effective_cpus, cs->effective_cpus);
     530                 :          0 :         return trial;
     531                 :            : }
     532                 :            : 
     533                 :            : /**
     534                 :            :  * free_cpuset - free the cpuset
     535                 :            :  * @cs: the cpuset to be freed
     536                 :            :  */
     537                 :          0 : static inline void free_cpuset(struct cpuset *cs)
     538                 :            : {
     539                 :          0 :         free_cpumasks(cs, NULL);
     540                 :          0 :         kfree(cs);
     541                 :          0 : }
     542                 :            : 
     543                 :            : /*
     544                 :            :  * validate_change() - Used to validate that any proposed cpuset change
     545                 :            :  *                     follows the structural rules for cpusets.
     546                 :            :  *
     547                 :            :  * If we replaced the flag and mask values of the current cpuset
     548                 :            :  * (cur) with those values in the trial cpuset (trial), would
     549                 :            :  * our various subset and exclusive rules still be valid?  Presumes
     550                 :            :  * cpuset_mutex held.
     551                 :            :  *
     552                 :            :  * 'cur' is the address of an actual, in-use cpuset.  Operations
     553                 :            :  * such as list traversal that depend on the actual address of the
     554                 :            :  * cpuset in the list must use cur below, not trial.
     555                 :            :  *
     556                 :            :  * 'trial' is the address of bulk structure copy of cur, with
     557                 :            :  * perhaps one or more of the fields cpus_allowed, mems_allowed,
     558                 :            :  * or flags changed to new, trial values.
     559                 :            :  *
     560                 :            :  * Return 0 if valid, -errno if not.
     561                 :            :  */
     562                 :            : 
     563                 :          0 : static int validate_change(struct cpuset *cur, struct cpuset *trial)
     564                 :            : {
     565                 :          0 :         struct cgroup_subsys_state *css;
     566                 :          0 :         struct cpuset *c, *par;
     567                 :          0 :         int ret;
     568                 :            : 
     569                 :          0 :         rcu_read_lock();
     570                 :            : 
     571                 :            :         /* Each of our child cpusets must be a subset of us */
     572                 :          0 :         ret = -EBUSY;
     573   [ #  #  #  # ]:          0 :         cpuset_for_each_child(c, css, cur)
     574         [ #  # ]:          0 :                 if (!is_cpuset_subset(c, trial))
     575                 :          0 :                         goto out;
     576                 :            : 
     577                 :            :         /* Remaining checks don't apply to root cpuset */
     578                 :          0 :         ret = 0;
     579         [ #  # ]:          0 :         if (cur == &top_cpuset)
     580                 :          0 :                 goto out;
     581                 :            : 
     582         [ #  # ]:          0 :         par = parent_cs(cur);
     583                 :            : 
     584                 :            :         /* On legacy hiearchy, we must be a subset of our parent cpuset. */
     585                 :          0 :         ret = -EACCES;
     586   [ #  #  #  #  :          0 :         if (!is_in_v2_mode() && !is_cpuset_subset(trial, par))
                   #  # ]
     587                 :          0 :                 goto out;
     588                 :            : 
     589                 :            :         /*
     590                 :            :          * If either I or some sibling (!= me) is exclusive, we can't
     591                 :            :          * overlap
     592                 :            :          */
     593                 :          0 :         ret = -EINVAL;
     594   [ #  #  #  # ]:          0 :         cpuset_for_each_child(c, css, par) {
     595   [ #  #  #  #  :          0 :                 if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
                   #  # ]
     596         [ #  # ]:          0 :                     c != cur &&
     597                 :            :                     cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
     598                 :          0 :                         goto out;
     599   [ #  #  #  #  :          0 :                 if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
                   #  # ]
     600         [ #  # ]:          0 :                     c != cur &&
     601                 :            :                     nodes_intersects(trial->mems_allowed, c->mems_allowed))
     602                 :          0 :                         goto out;
     603                 :            :         }
     604                 :            : 
     605                 :            :         /*
     606                 :            :          * Cpusets with tasks - existing or newly being attached - can't
     607                 :            :          * be changed to have empty cpus_allowed or mems_allowed.
     608                 :            :          */
     609                 :          0 :         ret = -ENOSPC;
     610   [ #  #  #  # ]:          0 :         if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) {
     611   [ #  #  #  # ]:          0 :                 if (!cpumask_empty(cur->cpus_allowed) &&
     612                 :            :                     cpumask_empty(trial->cpus_allowed))
     613                 :          0 :                         goto out;
     614   [ #  #  #  # ]:          0 :                 if (!nodes_empty(cur->mems_allowed) &&
     615                 :            :                     nodes_empty(trial->mems_allowed))
     616                 :          0 :                         goto out;
     617                 :            :         }
     618                 :            : 
     619                 :            :         /*
     620                 :            :          * We can't shrink if we won't have enough room for SCHED_DEADLINE
     621                 :            :          * tasks.
     622                 :            :          */
     623                 :          0 :         ret = -EBUSY;
     624   [ #  #  #  # ]:          0 :         if (is_cpu_exclusive(cur) &&
     625                 :          0 :             !cpuset_cpumask_can_shrink(cur->cpus_allowed,
     626                 :          0 :                                        trial->cpus_allowed))
     627                 :          0 :                 goto out;
     628                 :            : 
     629                 :            :         ret = 0;
     630                 :          0 : out:
     631                 :          0 :         rcu_read_unlock();
     632                 :          0 :         return ret;
     633                 :            : }
     634                 :            : 
     635                 :            : #ifdef CONFIG_SMP
     636                 :            : /*
     637                 :            :  * Helper routine for generate_sched_domains().
     638                 :            :  * Do cpusets a, b have overlapping effective cpus_allowed masks?
     639                 :            :  */
     640                 :          0 : static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
     641                 :            : {
     642         [ #  # ]:          0 :         return cpumask_intersects(a->effective_cpus, b->effective_cpus);
     643                 :            : }
     644                 :            : 
     645                 :            : static void
     646                 :          0 : update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
     647                 :            : {
     648                 :          0 :         if (dattr->relax_domain_level < c->relax_domain_level)
     649                 :          0 :                 dattr->relax_domain_level = c->relax_domain_level;
     650                 :            :         return;
     651                 :            : }
     652                 :            : 
     653                 :          0 : static void update_domain_attr_tree(struct sched_domain_attr *dattr,
     654                 :            :                                     struct cpuset *root_cs)
     655                 :            : {
     656                 :          0 :         struct cpuset *cp;
     657                 :          0 :         struct cgroup_subsys_state *pos_css;
     658                 :            : 
     659                 :          0 :         rcu_read_lock();
     660   [ #  #  #  # ]:          0 :         cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
     661                 :            :                 /* skip the whole subtree if @cp doesn't have any CPU */
     662         [ #  # ]:          0 :                 if (cpumask_empty(cp->cpus_allowed)) {
     663                 :          0 :                         pos_css = css_rightmost_descendant(pos_css);
     664                 :          0 :                         continue;
     665                 :            :                 }
     666                 :            : 
     667         [ #  # ]:          0 :                 if (is_sched_load_balance(cp))
     668         [ #  # ]:          0 :                         update_domain_attr(dattr, cp);
     669                 :            :         }
     670                 :          0 :         rcu_read_unlock();
     671                 :          0 : }
     672                 :            : 
     673                 :            : /* Must be called with cpuset_mutex held.  */
     674                 :          0 : static inline int nr_cpusets(void)
     675                 :            : {
     676                 :            :         /* jump label reference count + the top-level cpuset */
     677                 :          0 :         return static_key_count(&cpusets_enabled_key.key) + 1;
     678                 :            : }
     679                 :            : 
     680                 :            : /*
     681                 :            :  * generate_sched_domains()
     682                 :            :  *
     683                 :            :  * This function builds a partial partition of the systems CPUs
     684                 :            :  * A 'partial partition' is a set of non-overlapping subsets whose
     685                 :            :  * union is a subset of that set.
     686                 :            :  * The output of this function needs to be passed to kernel/sched/core.c
     687                 :            :  * partition_sched_domains() routine, which will rebuild the scheduler's
     688                 :            :  * load balancing domains (sched domains) as specified by that partial
     689                 :            :  * partition.
     690                 :            :  *
     691                 :            :  * See "What is sched_load_balance" in Documentation/admin-guide/cgroup-v1/cpusets.rst
     692                 :            :  * for a background explanation of this.
     693                 :            :  *
     694                 :            :  * Does not return errors, on the theory that the callers of this
     695                 :            :  * routine would rather not worry about failures to rebuild sched
     696                 :            :  * domains when operating in the severe memory shortage situations
     697                 :            :  * that could cause allocation failures below.
     698                 :            :  *
     699                 :            :  * Must be called with cpuset_mutex held.
     700                 :            :  *
     701                 :            :  * The three key local variables below are:
     702                 :            :  *    cp - cpuset pointer, used (together with pos_css) to perform a
     703                 :            :  *         top-down scan of all cpusets. For our purposes, rebuilding
     704                 :            :  *         the schedulers sched domains, we can ignore !is_sched_load_
     705                 :            :  *         balance cpusets.
     706                 :            :  *  csa  - (for CpuSet Array) Array of pointers to all the cpusets
     707                 :            :  *         that need to be load balanced, for convenient iterative
     708                 :            :  *         access by the subsequent code that finds the best partition,
     709                 :            :  *         i.e the set of domains (subsets) of CPUs such that the
     710                 :            :  *         cpus_allowed of every cpuset marked is_sched_load_balance
     711                 :            :  *         is a subset of one of these domains, while there are as
     712                 :            :  *         many such domains as possible, each as small as possible.
     713                 :            :  * doms  - Conversion of 'csa' to an array of cpumasks, for passing to
     714                 :            :  *         the kernel/sched/core.c routine partition_sched_domains() in a
     715                 :            :  *         convenient format, that can be easily compared to the prior
     716                 :            :  *         value to determine what partition elements (sched domains)
     717                 :            :  *         were changed (added or removed.)
     718                 :            :  *
     719                 :            :  * Finding the best partition (set of domains):
     720                 :            :  *      The triple nested loops below over i, j, k scan over the
     721                 :            :  *      load balanced cpusets (using the array of cpuset pointers in
     722                 :            :  *      csa[]) looking for pairs of cpusets that have overlapping
     723                 :            :  *      cpus_allowed, but which don't have the same 'pn' partition
     724                 :            :  *      number and gives them in the same partition number.  It keeps
     725                 :            :  *      looping on the 'restart' label until it can no longer find
     726                 :            :  *      any such pairs.
     727                 :            :  *
     728                 :            :  *      The union of the cpus_allowed masks from the set of
     729                 :            :  *      all cpusets having the same 'pn' value then form the one
     730                 :            :  *      element of the partition (one sched domain) to be passed to
     731                 :            :  *      partition_sched_domains().
     732                 :            :  */
     733                 :          0 : static int generate_sched_domains(cpumask_var_t **domains,
     734                 :            :                         struct sched_domain_attr **attributes)
     735                 :            : {
     736                 :          0 :         struct cpuset *cp;      /* top-down scan of cpusets */
     737                 :          0 :         struct cpuset **csa;    /* array of all cpuset ptrs */
     738                 :          0 :         int csn;                /* how many cpuset ptrs in csa so far */
     739                 :          0 :         int i, j, k;            /* indices for partition finding loops */
     740                 :          0 :         cpumask_var_t *doms;    /* resulting partition; i.e. sched domains */
     741                 :          0 :         struct sched_domain_attr *dattr;  /* attributes for custom domains */
     742                 :          0 :         int ndoms = 0;          /* number of sched domains in result */
     743                 :          0 :         int nslot;              /* next empty doms[] struct cpumask slot */
     744                 :          0 :         struct cgroup_subsys_state *pos_css;
     745                 :          0 :         bool root_load_balance = is_sched_load_balance(&top_cpuset);
     746                 :            : 
     747                 :          0 :         doms = NULL;
     748                 :          0 :         dattr = NULL;
     749                 :          0 :         csa = NULL;
     750                 :            : 
     751                 :            :         /* Special case for the 99% of systems with one, full, sched domain */
     752   [ #  #  #  # ]:          0 :         if (root_load_balance && !top_cpuset.nr_subparts_cpus) {
     753                 :          0 :                 ndoms = 1;
     754                 :          0 :                 doms = alloc_sched_domains(ndoms);
     755         [ #  # ]:          0 :                 if (!doms)
     756                 :          0 :                         goto done;
     757                 :            : 
     758                 :          0 :                 dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
     759         [ #  # ]:          0 :                 if (dattr) {
     760                 :          0 :                         *dattr = SD_ATTR_INIT;
     761                 :          0 :                         update_domain_attr_tree(dattr, &top_cpuset);
     762                 :            :                 }
     763                 :          0 :                 cpumask_and(doms[0], top_cpuset.effective_cpus,
     764                 :            :                             housekeeping_cpumask(HK_FLAG_DOMAIN));
     765                 :            : 
     766                 :          0 :                 goto done;
     767                 :            :         }
     768                 :            : 
     769                 :          0 :         csa = kmalloc_array(nr_cpusets(), sizeof(cp), GFP_KERNEL);
     770         [ #  # ]:          0 :         if (!csa)
     771                 :          0 :                 goto done;
     772                 :          0 :         csn = 0;
     773                 :            : 
     774                 :          0 :         rcu_read_lock();
     775         [ #  # ]:          0 :         if (root_load_balance)
     776                 :          0 :                 csa[csn++] = &top_cpuset;
     777   [ #  #  #  # ]:          0 :         cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) {
     778         [ #  # ]:          0 :                 if (cp == &top_cpuset)
     779                 :          0 :                         continue;
     780                 :            :                 /*
     781                 :            :                  * Continue traversing beyond @cp iff @cp has some CPUs and
     782                 :            :                  * isn't load balancing.  The former is obvious.  The
     783                 :            :                  * latter: All child cpusets contain a subset of the
     784                 :            :                  * parent's cpus, so just skip them, and then we call
     785                 :            :                  * update_domain_attr_tree() to calc relax_domain_level of
     786                 :            :                  * the corresponding sched domain.
     787                 :            :                  *
     788                 :            :                  * If root is load-balancing, we can skip @cp if it
     789                 :            :                  * is a subset of the root's effective_cpus.
     790                 :            :                  */
     791   [ #  #  #  # ]:          0 :                 if (!cpumask_empty(cp->cpus_allowed) &&
     792         [ #  # ]:          0 :                     !(is_sched_load_balance(cp) &&
     793                 :          0 :                       cpumask_intersects(cp->cpus_allowed,
     794                 :            :                                          housekeeping_cpumask(HK_FLAG_DOMAIN))))
     795                 :          0 :                         continue;
     796                 :            : 
     797   [ #  #  #  # ]:          0 :                 if (root_load_balance &&
     798                 :            :                     cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus))
     799                 :          0 :                         continue;
     800                 :            : 
     801   [ #  #  #  # ]:          0 :                 if (is_sched_load_balance(cp) &&
     802                 :            :                     !cpumask_empty(cp->effective_cpus))
     803                 :          0 :                         csa[csn++] = cp;
     804                 :            : 
     805                 :            :                 /* skip @cp's subtree if not a partition root */
     806         [ #  # ]:          0 :                 if (!is_partition_root(cp))
     807                 :          0 :                         pos_css = css_rightmost_descendant(pos_css);
     808                 :            :         }
     809                 :          0 :         rcu_read_unlock();
     810                 :            : 
     811         [ #  # ]:          0 :         for (i = 0; i < csn; i++)
     812                 :          0 :                 csa[i]->pn = i;
     813                 :            :         ndoms = csn;
     814                 :            : 
     815                 :          0 : restart:
     816                 :            :         /* Find the best partition (set of sched domains) */
     817         [ #  # ]:          0 :         for (i = 0; i < csn; i++) {
     818                 :          0 :                 struct cpuset *a = csa[i];
     819                 :          0 :                 int apn = a->pn;
     820                 :            : 
     821         [ #  # ]:          0 :                 for (j = 0; j < csn; j++) {
     822                 :          0 :                         struct cpuset *b = csa[j];
     823                 :          0 :                         int bpn = b->pn;
     824                 :            : 
     825   [ #  #  #  # ]:          0 :                         if (apn != bpn && cpusets_overlap(a, b)) {
     826         [ #  # ]:          0 :                                 for (k = 0; k < csn; k++) {
     827                 :          0 :                                         struct cpuset *c = csa[k];
     828                 :            : 
     829         [ #  # ]:          0 :                                         if (c->pn == bpn)
     830                 :          0 :                                                 c->pn = apn;
     831                 :            :                                 }
     832                 :          0 :                                 ndoms--;        /* one less element */
     833                 :          0 :                                 goto restart;
     834                 :            :                         }
     835                 :            :                 }
     836                 :            :         }
     837                 :            : 
     838                 :            :         /*
     839                 :            :          * Now we know how many domains to create.
     840                 :            :          * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
     841                 :            :          */
     842                 :          0 :         doms = alloc_sched_domains(ndoms);
     843         [ #  # ]:          0 :         if (!doms)
     844                 :          0 :                 goto done;
     845                 :            : 
     846                 :            :         /*
     847                 :            :          * The rest of the code, including the scheduler, can deal with
     848                 :            :          * dattr==NULL case. No need to abort if alloc fails.
     849                 :            :          */
     850                 :          0 :         dattr = kmalloc_array(ndoms, sizeof(struct sched_domain_attr),
     851                 :            :                               GFP_KERNEL);
     852                 :            : 
     853         [ #  # ]:          0 :         for (nslot = 0, i = 0; i < csn; i++) {
     854                 :          0 :                 struct cpuset *a = csa[i];
     855                 :          0 :                 struct cpumask *dp;
     856                 :          0 :                 int apn = a->pn;
     857                 :            : 
     858         [ #  # ]:          0 :                 if (apn < 0) {
     859                 :            :                         /* Skip completed partitions */
     860                 :          0 :                         continue;
     861                 :            :                 }
     862                 :            : 
     863                 :          0 :                 dp = doms[nslot];
     864                 :            : 
     865         [ #  # ]:          0 :                 if (nslot == ndoms) {
     866                 :          0 :                         static int warnings = 10;
     867         [ #  # ]:          0 :                         if (warnings) {
     868                 :          0 :                                 pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
     869                 :            :                                         nslot, ndoms, csn, i, apn);
     870                 :          0 :                                 warnings--;
     871                 :            :                         }
     872                 :          0 :                         continue;
     873                 :            :                 }
     874                 :            : 
     875         [ #  # ]:          0 :                 cpumask_clear(dp);
     876         [ #  # ]:          0 :                 if (dattr)
     877                 :          0 :                         *(dattr + nslot) = SD_ATTR_INIT;
     878         [ #  # ]:          0 :                 for (j = i; j < csn; j++) {
     879                 :          0 :                         struct cpuset *b = csa[j];
     880                 :            : 
     881         [ #  # ]:          0 :                         if (apn == b->pn) {
     882                 :          0 :                                 cpumask_or(dp, dp, b->effective_cpus);
     883                 :          0 :                                 cpumask_and(dp, dp, housekeeping_cpumask(HK_FLAG_DOMAIN));
     884         [ #  # ]:          0 :                                 if (dattr)
     885                 :          0 :                                         update_domain_attr_tree(dattr + nslot, b);
     886                 :            : 
     887                 :            :                                 /* Done with this partition */
     888                 :          0 :                                 b->pn = -1;
     889                 :            :                         }
     890                 :            :                 }
     891                 :          0 :                 nslot++;
     892                 :            :         }
     893         [ #  # ]:          0 :         BUG_ON(nslot != ndoms);
     894                 :            : 
     895                 :          0 : done:
     896                 :          0 :         kfree(csa);
     897                 :            : 
     898                 :            :         /*
     899                 :            :          * Fallback to the default domain if kmalloc() failed.
     900                 :            :          * See comments in partition_sched_domains().
     901                 :            :          */
     902         [ #  # ]:          0 :         if (doms == NULL)
     903                 :          0 :                 ndoms = 1;
     904                 :            : 
     905                 :          0 :         *domains    = doms;
     906                 :          0 :         *attributes = dattr;
     907                 :          0 :         return ndoms;
     908                 :            : }
     909                 :            : 
     910                 :          0 : static void update_tasks_root_domain(struct cpuset *cs)
     911                 :            : {
     912                 :          0 :         struct css_task_iter it;
     913                 :          0 :         struct task_struct *task;
     914                 :            : 
     915                 :          0 :         css_task_iter_start(&cs->css, 0, &it);
     916                 :            : 
     917         [ #  # ]:          0 :         while ((task = css_task_iter_next(&it)))
     918                 :          0 :                 dl_add_task_root_domain(task);
     919                 :            : 
     920                 :          0 :         css_task_iter_end(&it);
     921                 :          0 : }
     922                 :            : 
     923                 :          0 : static void rebuild_root_domains(void)
     924                 :            : {
     925                 :          0 :         struct cpuset *cs = NULL;
     926                 :          0 :         struct cgroup_subsys_state *pos_css;
     927                 :            : 
     928                 :          0 :         percpu_rwsem_assert_held(&cpuset_rwsem);
     929                 :          0 :         lockdep_assert_cpus_held();
     930                 :          0 :         lockdep_assert_held(&sched_domains_mutex);
     931                 :            : 
     932                 :          0 :         rcu_read_lock();
     933                 :            : 
     934                 :            :         /*
     935                 :            :          * Clear default root domain DL accounting, it will be computed again
     936                 :            :          * if a task belongs to it.
     937                 :            :          */
     938                 :          0 :         dl_clear_root_domain(&def_root_domain);
     939                 :            : 
     940   [ #  #  #  # ]:          0 :         cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
     941                 :            : 
     942         [ #  # ]:          0 :                 if (cpumask_empty(cs->effective_cpus)) {
     943                 :          0 :                         pos_css = css_rightmost_descendant(pos_css);
     944                 :          0 :                         continue;
     945                 :            :                 }
     946                 :            : 
     947         [ #  # ]:          0 :                 css_get(&cs->css);
     948                 :            : 
     949                 :          0 :                 rcu_read_unlock();
     950                 :            : 
     951                 :          0 :                 update_tasks_root_domain(cs);
     952                 :            : 
     953                 :          0 :                 rcu_read_lock();
     954         [ #  # ]:          0 :                 css_put(&cs->css);
     955                 :            :         }
     956                 :          0 :         rcu_read_unlock();
     957                 :          0 : }
     958                 :            : 
     959                 :            : static void
     960                 :          0 : partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
     961                 :            :                                     struct sched_domain_attr *dattr_new)
     962                 :            : {
     963                 :          0 :         mutex_lock(&sched_domains_mutex);
     964                 :          0 :         partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
     965                 :          0 :         rebuild_root_domains();
     966                 :          0 :         mutex_unlock(&sched_domains_mutex);
     967                 :          0 : }
     968                 :            : 
     969                 :            : /*
     970                 :            :  * Rebuild scheduler domains.
     971                 :            :  *
     972                 :            :  * If the flag 'sched_load_balance' of any cpuset with non-empty
     973                 :            :  * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
     974                 :            :  * which has that flag enabled, or if any cpuset with a non-empty
     975                 :            :  * 'cpus' is removed, then call this routine to rebuild the
     976                 :            :  * scheduler's dynamic sched domains.
     977                 :            :  *
     978                 :            :  * Call with cpuset_mutex held.  Takes get_online_cpus().
     979                 :            :  */
     980                 :          0 : static void rebuild_sched_domains_locked(void)
     981                 :            : {
     982                 :          0 :         struct sched_domain_attr *attr;
     983                 :          0 :         cpumask_var_t *doms;
     984                 :          0 :         int ndoms;
     985                 :            : 
     986                 :          0 :         lockdep_assert_cpus_held();
     987                 :          0 :         percpu_rwsem_assert_held(&cpuset_rwsem);
     988                 :            : 
     989                 :            :         /*
     990                 :            :          * We have raced with CPU hotplug. Don't do anything to avoid
     991                 :            :          * passing doms with offlined cpu to partition_sched_domains().
     992                 :            :          * Anyways, hotplug work item will rebuild sched domains.
     993                 :            :          */
     994   [ #  #  #  # ]:          0 :         if (!top_cpuset.nr_subparts_cpus &&
     995                 :            :             !cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
     996                 :          0 :                 return;
     997                 :            : 
     998   [ #  #  #  # ]:          0 :         if (top_cpuset.nr_subparts_cpus &&
     999                 :            :            !cpumask_subset(top_cpuset.effective_cpus, cpu_active_mask))
    1000                 :            :                 return;
    1001                 :            : 
    1002                 :            :         /* Generate domain masks and attrs */
    1003                 :          0 :         ndoms = generate_sched_domains(&doms, &attr);
    1004                 :            : 
    1005                 :            :         /* Have scheduler rebuild the domains */
    1006                 :          0 :         partition_and_rebuild_sched_domains(ndoms, doms, attr);
    1007                 :            : }
    1008                 :            : #else /* !CONFIG_SMP */
    1009                 :            : static void rebuild_sched_domains_locked(void)
    1010                 :            : {
    1011                 :            : }
    1012                 :            : #endif /* CONFIG_SMP */
    1013                 :            : 
    1014                 :          0 : void rebuild_sched_domains(void)
    1015                 :            : {
    1016                 :          0 :         get_online_cpus();
    1017                 :          0 :         percpu_down_write(&cpuset_rwsem);
    1018                 :          0 :         rebuild_sched_domains_locked();
    1019                 :          0 :         percpu_up_write(&cpuset_rwsem);
    1020                 :          0 :         put_online_cpus();
    1021                 :          0 : }
    1022                 :            : 
    1023                 :            : /**
    1024                 :            :  * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
    1025                 :            :  * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
    1026                 :            :  *
    1027                 :            :  * Iterate through each task of @cs updating its cpus_allowed to the
    1028                 :            :  * effective cpuset's.  As this function is called with cpuset_mutex held,
    1029                 :            :  * cpuset membership stays stable.
    1030                 :            :  */
    1031                 :          0 : static void update_tasks_cpumask(struct cpuset *cs)
    1032                 :            : {
    1033                 :          0 :         struct css_task_iter it;
    1034                 :          0 :         struct task_struct *task;
    1035                 :            : 
    1036                 :          0 :         css_task_iter_start(&cs->css, 0, &it);
    1037         [ #  # ]:          0 :         while ((task = css_task_iter_next(&it)))
    1038                 :          0 :                 set_cpus_allowed_ptr(task, cs->effective_cpus);
    1039                 :          0 :         css_task_iter_end(&it);
    1040                 :          0 : }
    1041                 :            : 
    1042                 :            : /**
    1043                 :            :  * compute_effective_cpumask - Compute the effective cpumask of the cpuset
    1044                 :            :  * @new_cpus: the temp variable for the new effective_cpus mask
    1045                 :            :  * @cs: the cpuset the need to recompute the new effective_cpus mask
    1046                 :            :  * @parent: the parent cpuset
    1047                 :            :  *
    1048                 :            :  * If the parent has subpartition CPUs, include them in the list of
    1049                 :            :  * allowable CPUs in computing the new effective_cpus mask. Since offlined
    1050                 :            :  * CPUs are not removed from subparts_cpus, we have to use cpu_active_mask
    1051                 :            :  * to mask those out.
    1052                 :            :  */
    1053                 :          0 : static void compute_effective_cpumask(struct cpumask *new_cpus,
    1054                 :            :                                       struct cpuset *cs, struct cpuset *parent)
    1055                 :            : {
    1056                 :          0 :         if (parent->nr_subparts_cpus) {
    1057                 :          0 :                 cpumask_or(new_cpus, parent->effective_cpus,
    1058                 :            :                            parent->subparts_cpus);
    1059                 :          0 :                 cpumask_and(new_cpus, new_cpus, cs->cpus_allowed);
    1060                 :          0 :                 cpumask_and(new_cpus, new_cpus, cpu_active_mask);
    1061                 :            :         } else {
    1062                 :          0 :                 cpumask_and(new_cpus, cs->cpus_allowed, parent->effective_cpus);
    1063                 :            :         }
    1064                 :            : }
    1065                 :            : 
    1066                 :            : /*
    1067                 :            :  * Commands for update_parent_subparts_cpumask
    1068                 :            :  */
    1069                 :            : enum subparts_cmd {
    1070                 :            :         partcmd_enable,         /* Enable partition root         */
    1071                 :            :         partcmd_disable,        /* Disable partition root        */
    1072                 :            :         partcmd_update,         /* Update parent's subparts_cpus */
    1073                 :            : };
    1074                 :            : 
    1075                 :            : /**
    1076                 :            :  * update_parent_subparts_cpumask - update subparts_cpus mask of parent cpuset
    1077                 :            :  * @cpuset:  The cpuset that requests change in partition root state
    1078                 :            :  * @cmd:     Partition root state change command
    1079                 :            :  * @newmask: Optional new cpumask for partcmd_update
    1080                 :            :  * @tmp:     Temporary addmask and delmask
    1081                 :            :  * Return:   0, 1 or an error code
    1082                 :            :  *
    1083                 :            :  * For partcmd_enable, the cpuset is being transformed from a non-partition
    1084                 :            :  * root to a partition root. The cpus_allowed mask of the given cpuset will
    1085                 :            :  * be put into parent's subparts_cpus and taken away from parent's
    1086                 :            :  * effective_cpus. The function will return 0 if all the CPUs listed in
    1087                 :            :  * cpus_allowed can be granted or an error code will be returned.
    1088                 :            :  *
    1089                 :            :  * For partcmd_disable, the cpuset is being transofrmed from a partition
    1090                 :            :  * root back to a non-partition root. any CPUs in cpus_allowed that are in
    1091                 :            :  * parent's subparts_cpus will be taken away from that cpumask and put back
    1092                 :            :  * into parent's effective_cpus. 0 should always be returned.
    1093                 :            :  *
    1094                 :            :  * For partcmd_update, if the optional newmask is specified, the cpu
    1095                 :            :  * list is to be changed from cpus_allowed to newmask. Otherwise,
    1096                 :            :  * cpus_allowed is assumed to remain the same. The cpuset should either
    1097                 :            :  * be a partition root or an invalid partition root. The partition root
    1098                 :            :  * state may change if newmask is NULL and none of the requested CPUs can
    1099                 :            :  * be granted by the parent. The function will return 1 if changes to
    1100                 :            :  * parent's subparts_cpus and effective_cpus happen or 0 otherwise.
    1101                 :            :  * Error code should only be returned when newmask is non-NULL.
    1102                 :            :  *
    1103                 :            :  * The partcmd_enable and partcmd_disable commands are used by
    1104                 :            :  * update_prstate(). The partcmd_update command is used by
    1105                 :            :  * update_cpumasks_hier() with newmask NULL and update_cpumask() with
    1106                 :            :  * newmask set.
    1107                 :            :  *
    1108                 :            :  * The checking is more strict when enabling partition root than the
    1109                 :            :  * other two commands.
    1110                 :            :  *
    1111                 :            :  * Because of the implicit cpu exclusive nature of a partition root,
    1112                 :            :  * cpumask changes that violates the cpu exclusivity rule will not be
    1113                 :            :  * permitted when checked by validate_change(). The validate_change()
    1114                 :            :  * function will also prevent any changes to the cpu list if it is not
    1115                 :            :  * a superset of children's cpu lists.
    1116                 :            :  */
    1117                 :          0 : static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
    1118                 :            :                                           struct cpumask *newmask,
    1119                 :            :                                           struct tmpmasks *tmp)
    1120                 :            : {
    1121         [ #  # ]:          0 :         struct cpuset *parent = parent_cs(cpuset);
    1122                 :          0 :         int adding;     /* Moving cpus from effective_cpus to subparts_cpus */
    1123                 :          0 :         int deleting;   /* Moving cpus from subparts_cpus to effective_cpus */
    1124                 :          0 :         bool part_error = false;        /* Partition error? */
    1125                 :            : 
    1126                 :          0 :         percpu_rwsem_assert_held(&cpuset_rwsem);
    1127                 :            : 
    1128                 :            :         /*
    1129                 :            :          * The parent must be a partition root.
    1130                 :            :          * The new cpumask, if present, or the current cpus_allowed must
    1131                 :            :          * not be empty.
    1132                 :            :          */
    1133   [ #  #  #  # ]:          0 :         if (!is_partition_root(parent) ||
    1134   [ #  #  #  # ]:          0 :            (newmask && cpumask_empty(newmask)) ||
    1135         [ #  # ]:          0 :            (!newmask && cpumask_empty(cpuset->cpus_allowed)))
    1136                 :            :                 return -EINVAL;
    1137                 :            : 
    1138                 :            :         /*
    1139                 :            :          * Enabling/disabling partition root is not allowed if there are
    1140                 :            :          * online children.
    1141                 :            :          */
    1142   [ #  #  #  # ]:          0 :         if ((cmd != partcmd_update) && css_has_online_children(&cpuset->css))
    1143                 :            :                 return -EBUSY;
    1144                 :            : 
    1145                 :            :         /*
    1146                 :            :          * Enabling partition root is not allowed if not all the CPUs
    1147                 :            :          * can be granted from parent's effective_cpus or at least one
    1148                 :            :          * CPU will be left after that.
    1149                 :            :          */
    1150   [ #  #  #  # ]:          0 :         if ((cmd == partcmd_enable) &&
    1151         [ #  # ]:          0 :            (!cpumask_subset(cpuset->cpus_allowed, parent->effective_cpus) ||
    1152                 :            :              cpumask_equal(cpuset->cpus_allowed, parent->effective_cpus)))
    1153                 :          0 :                 return -EINVAL;
    1154                 :            : 
    1155                 :            :         /*
    1156                 :            :          * A cpumask update cannot make parent's effective_cpus become empty.
    1157                 :            :          */
    1158                 :          0 :         adding = deleting = false;
    1159         [ #  # ]:          0 :         if (cmd == partcmd_enable) {
    1160                 :          0 :                 cpumask_copy(tmp->addmask, cpuset->cpus_allowed);
    1161                 :          0 :                 adding = true;
    1162         [ #  # ]:          0 :         } else if (cmd == partcmd_disable) {
    1163                 :          0 :                 deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
    1164                 :            :                                        parent->subparts_cpus);
    1165         [ #  # ]:          0 :         } else if (newmask) {
    1166                 :            :                 /*
    1167                 :            :                  * partcmd_update with newmask:
    1168                 :            :                  *
    1169                 :            :                  * delmask = cpus_allowed & ~newmask & parent->subparts_cpus
    1170                 :            :                  * addmask = newmask & parent->effective_cpus
    1171                 :            :                  *                   & ~parent->subparts_cpus
    1172                 :            :                  */
    1173         [ #  # ]:          0 :                 cpumask_andnot(tmp->delmask, cpuset->cpus_allowed, newmask);
    1174         [ #  # ]:          0 :                 deleting = cpumask_and(tmp->delmask, tmp->delmask,
    1175                 :            :                                        parent->subparts_cpus);
    1176                 :            : 
    1177                 :          0 :                 cpumask_and(tmp->addmask, newmask, parent->effective_cpus);
    1178                 :          0 :                 adding = cpumask_andnot(tmp->addmask, tmp->addmask,
    1179                 :            :                                         parent->subparts_cpus);
    1180                 :            :                 /*
    1181                 :            :                  * Return error if the new effective_cpus could become empty.
    1182                 :            :                  */
    1183   [ #  #  #  # ]:          0 :                 if (adding &&
    1184                 :            :                     cpumask_equal(parent->effective_cpus, tmp->addmask)) {
    1185         [ #  # ]:          0 :                         if (!deleting)
    1186                 :            :                                 return -EINVAL;
    1187                 :            :                         /*
    1188                 :            :                          * As some of the CPUs in subparts_cpus might have
    1189                 :            :                          * been offlined, we need to compute the real delmask
    1190                 :            :                          * to confirm that.
    1191                 :            :                          */
    1192         [ #  # ]:          0 :                         if (!cpumask_and(tmp->addmask, tmp->delmask,
    1193                 :            :                                          cpu_active_mask))
    1194                 :            :                                 return -EINVAL;
    1195                 :          0 :                         cpumask_copy(tmp->addmask, parent->effective_cpus);
    1196                 :            :                 }
    1197                 :            :         } else {
    1198                 :            :                 /*
    1199                 :            :                  * partcmd_update w/o newmask:
    1200                 :            :                  *
    1201                 :            :                  * addmask = cpus_allowed & parent->effectiveb_cpus
    1202                 :            :                  *
    1203                 :            :                  * Note that parent's subparts_cpus may have been
    1204                 :            :                  * pre-shrunk in case there is a change in the cpu list.
    1205                 :            :                  * So no deletion is needed.
    1206                 :            :                  */
    1207                 :          0 :                 adding = cpumask_and(tmp->addmask, cpuset->cpus_allowed,
    1208                 :            :                                      parent->effective_cpus);
    1209                 :          0 :                 part_error = cpumask_equal(tmp->addmask,
    1210                 :            :                                            parent->effective_cpus);
    1211                 :            :         }
    1212                 :            : 
    1213         [ #  # ]:          0 :         if (cmd == partcmd_update) {
    1214                 :          0 :                 int prev_prs = cpuset->partition_root_state;
    1215                 :            : 
    1216                 :            :                 /*
    1217                 :            :                  * Check for possible transition between PRS_ENABLED
    1218                 :            :                  * and PRS_ERROR.
    1219                 :            :                  */
    1220      [ #  #  # ]:          0 :                 switch (cpuset->partition_root_state) {
    1221                 :          0 :                 case PRS_ENABLED:
    1222         [ #  # ]:          0 :                         if (part_error)
    1223                 :          0 :                                 cpuset->partition_root_state = PRS_ERROR;
    1224                 :            :                         break;
    1225                 :          0 :                 case PRS_ERROR:
    1226         [ #  # ]:          0 :                         if (!part_error)
    1227                 :          0 :                                 cpuset->partition_root_state = PRS_ENABLED;
    1228                 :            :                         break;
    1229                 :            :                 }
    1230                 :            :                 /*
    1231                 :            :                  * Set part_error if previously in invalid state.
    1232                 :            :                  */
    1233                 :          0 :                 part_error = (prev_prs == PRS_ERROR);
    1234                 :            :         }
    1235                 :            : 
    1236   [ #  #  #  # ]:          0 :         if (!part_error && (cpuset->partition_root_state == PRS_ERROR))
    1237                 :            :                 return 0;       /* Nothing need to be done */
    1238                 :            : 
    1239         [ #  # ]:          0 :         if (cpuset->partition_root_state == PRS_ERROR) {
    1240                 :            :                 /*
    1241                 :            :                  * Remove all its cpus from parent's subparts_cpus.
    1242                 :            :                  */
    1243                 :          0 :                 adding = false;
    1244                 :          0 :                 deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
    1245                 :            :                                        parent->subparts_cpus);
    1246                 :            :         }
    1247                 :            : 
    1248         [ #  # ]:          0 :         if (!adding && !deleting)
    1249                 :            :                 return 0;
    1250                 :            : 
    1251                 :            :         /*
    1252                 :            :          * Change the parent's subparts_cpus.
    1253                 :            :          * Newly added CPUs will be removed from effective_cpus and
    1254                 :            :          * newly deleted ones will be added back to effective_cpus.
    1255                 :            :          */
    1256                 :          0 :         spin_lock_irq(&callback_lock);
    1257         [ #  # ]:          0 :         if (adding) {
    1258                 :          0 :                 cpumask_or(parent->subparts_cpus,
    1259                 :            :                            parent->subparts_cpus, tmp->addmask);
    1260                 :          0 :                 cpumask_andnot(parent->effective_cpus,
    1261                 :            :                                parent->effective_cpus, tmp->addmask);
    1262                 :            :         }
    1263         [ #  # ]:          0 :         if (deleting) {
    1264                 :          0 :                 cpumask_andnot(parent->subparts_cpus,
    1265                 :            :                                parent->subparts_cpus, tmp->delmask);
    1266                 :            :                 /*
    1267                 :            :                  * Some of the CPUs in subparts_cpus might have been offlined.
    1268                 :            :                  */
    1269                 :          0 :                 cpumask_and(tmp->delmask, tmp->delmask, cpu_active_mask);
    1270                 :          0 :                 cpumask_or(parent->effective_cpus,
    1271                 :            :                            parent->effective_cpus, tmp->delmask);
    1272                 :            :         }
    1273                 :            : 
    1274                 :          0 :         parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus);
    1275                 :          0 :         spin_unlock_irq(&callback_lock);
    1276                 :            : 
    1277                 :          0 :         return cmd == partcmd_update;
    1278                 :            : }
    1279                 :            : 
    1280                 :            : /*
    1281                 :            :  * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
    1282                 :            :  * @cs:  the cpuset to consider
    1283                 :            :  * @tmp: temp variables for calculating effective_cpus & partition setup
    1284                 :            :  *
    1285                 :            :  * When congifured cpumask is changed, the effective cpumasks of this cpuset
    1286                 :            :  * and all its descendants need to be updated.
    1287                 :            :  *
    1288                 :            :  * On legacy hierachy, effective_cpus will be the same with cpu_allowed.
    1289                 :            :  *
    1290                 :            :  * Called with cpuset_mutex held
    1291                 :            :  */
    1292                 :          0 : static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
    1293                 :            : {
    1294                 :          0 :         struct cpuset *cp;
    1295                 :          0 :         struct cgroup_subsys_state *pos_css;
    1296                 :          0 :         bool need_rebuild_sched_domains = false;
    1297                 :            : 
    1298                 :          0 :         rcu_read_lock();
    1299   [ #  #  #  # ]:          0 :         cpuset_for_each_descendant_pre(cp, pos_css, cs) {
    1300         [ #  # ]:          0 :                 struct cpuset *parent = parent_cs(cp);
    1301                 :            : 
    1302         [ #  # ]:          0 :                 compute_effective_cpumask(tmp->new_cpus, cp, parent);
    1303                 :            : 
    1304                 :            :                 /*
    1305                 :            :                  * If it becomes empty, inherit the effective mask of the
    1306                 :            :                  * parent, which is guaranteed to have some CPUs.
    1307                 :            :                  */
    1308   [ #  #  #  #  :          0 :                 if (is_in_v2_mode() && cpumask_empty(tmp->new_cpus)) {
                   #  # ]
    1309         [ #  # ]:          0 :                         cpumask_copy(tmp->new_cpus, parent->effective_cpus);
    1310         [ #  # ]:          0 :                         if (!cp->use_parent_ecpus) {
    1311                 :          0 :                                 cp->use_parent_ecpus = true;
    1312                 :          0 :                                 parent->child_ecpus_count++;
    1313                 :            :                         }
    1314         [ #  # ]:          0 :                 } else if (cp->use_parent_ecpus) {
    1315                 :          0 :                         cp->use_parent_ecpus = false;
    1316         [ #  # ]:          0 :                         WARN_ON_ONCE(!parent->child_ecpus_count);
    1317                 :          0 :                         parent->child_ecpus_count--;
    1318                 :            :                 }
    1319                 :            : 
    1320                 :            :                 /*
    1321                 :            :                  * Skip the whole subtree if the cpumask remains the same
    1322                 :            :                  * and has no partition root state.
    1323                 :            :                  */
    1324   [ #  #  #  # ]:          0 :                 if (!cp->partition_root_state &&
    1325                 :            :                     cpumask_equal(tmp->new_cpus, cp->effective_cpus)) {
    1326                 :          0 :                         pos_css = css_rightmost_descendant(pos_css);
    1327                 :          0 :                         continue;
    1328                 :            :                 }
    1329                 :            : 
    1330                 :            :                 /*
    1331                 :            :                  * update_parent_subparts_cpumask() should have been called
    1332                 :            :                  * for cs already in update_cpumask(). We should also call
    1333                 :            :                  * update_tasks_cpumask() again for tasks in the parent
    1334                 :            :                  * cpuset if the parent's subparts_cpus changes.
    1335                 :            :                  */
    1336   [ #  #  #  # ]:          0 :                 if ((cp != cs) && cp->partition_root_state) {
    1337   [ #  #  #  # ]:          0 :                         switch (parent->partition_root_state) {
    1338                 :          0 :                         case PRS_DISABLED:
    1339                 :            :                                 /*
    1340                 :            :                                  * If parent is not a partition root or an
    1341                 :            :                                  * invalid partition root, clear the state
    1342                 :            :                                  * state and the CS_CPU_EXCLUSIVE flag.
    1343                 :            :                                  */
    1344         [ #  # ]:          0 :                                 WARN_ON_ONCE(cp->partition_root_state
    1345                 :            :                                              != PRS_ERROR);
    1346                 :          0 :                                 cp->partition_root_state = 0;
    1347                 :            : 
    1348                 :            :                                 /*
    1349                 :            :                                  * clear_bit() is an atomic operation and
    1350                 :            :                                  * readers aren't interested in the state
    1351                 :            :                                  * of CS_CPU_EXCLUSIVE anyway. So we can
    1352                 :            :                                  * just update the flag without holding
    1353                 :            :                                  * the callback_lock.
    1354                 :            :                                  */
    1355                 :          0 :                                 clear_bit(CS_CPU_EXCLUSIVE, &cp->flags);
    1356                 :          0 :                                 break;
    1357                 :            : 
    1358                 :          0 :                         case PRS_ENABLED:
    1359         [ #  # ]:          0 :                                 if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp))
    1360                 :          0 :                                         update_tasks_cpumask(parent);
    1361                 :            :                                 break;
    1362                 :            : 
    1363                 :          0 :                         case PRS_ERROR:
    1364                 :            :                                 /*
    1365                 :            :                                  * When parent is invalid, it has to be too.
    1366                 :            :                                  */
    1367                 :          0 :                                 cp->partition_root_state = PRS_ERROR;
    1368         [ #  # ]:          0 :                                 if (cp->nr_subparts_cpus) {
    1369                 :          0 :                                         cp->nr_subparts_cpus = 0;
    1370                 :          0 :                                         cpumask_clear(cp->subparts_cpus);
    1371                 :            :                                 }
    1372                 :            :                                 break;
    1373                 :            :                         }
    1374                 :          0 :                 }
    1375                 :            : 
    1376   [ #  #  #  # ]:          0 :                 if (!css_tryget_online(&cp->css))
    1377                 :          0 :                         continue;
    1378                 :          0 :                 rcu_read_unlock();
    1379                 :            : 
    1380                 :          0 :                 spin_lock_irq(&callback_lock);
    1381                 :            : 
    1382         [ #  # ]:          0 :                 cpumask_copy(cp->effective_cpus, tmp->new_cpus);
    1383         [ #  # ]:          0 :                 if (cp->nr_subparts_cpus &&
    1384         [ #  # ]:          0 :                    (cp->partition_root_state != PRS_ENABLED)) {
    1385                 :          0 :                         cp->nr_subparts_cpus = 0;
    1386                 :          0 :                         cpumask_clear(cp->subparts_cpus);
    1387         [ #  # ]:          0 :                 } else if (cp->nr_subparts_cpus) {
    1388                 :            :                         /*
    1389                 :            :                          * Make sure that effective_cpus & subparts_cpus
    1390                 :            :                          * are mutually exclusive.
    1391                 :            :                          *
    1392                 :            :                          * In the unlikely event that effective_cpus
    1393                 :            :                          * becomes empty. we clear cp->nr_subparts_cpus and
    1394                 :            :                          * let its child partition roots to compete for
    1395                 :            :                          * CPUs again.
    1396                 :            :                          */
    1397         [ #  # ]:          0 :                         cpumask_andnot(cp->effective_cpus, cp->effective_cpus,
    1398                 :            :                                        cp->subparts_cpus);
    1399         [ #  # ]:          0 :                         if (cpumask_empty(cp->effective_cpus)) {
    1400                 :          0 :                                 cpumask_copy(cp->effective_cpus, tmp->new_cpus);
    1401                 :          0 :                                 cpumask_clear(cp->subparts_cpus);
    1402                 :          0 :                                 cp->nr_subparts_cpus = 0;
    1403         [ #  # ]:          0 :                         } else if (!cpumask_subset(cp->subparts_cpus,
    1404                 :            :                                                    tmp->new_cpus)) {
    1405                 :          0 :                                 cpumask_andnot(cp->subparts_cpus,
    1406                 :            :                                         cp->subparts_cpus, tmp->new_cpus);
    1407                 :          0 :                                 cp->nr_subparts_cpus
    1408                 :          0 :                                         = cpumask_weight(cp->subparts_cpus);
    1409                 :            :                         }
    1410                 :            :                 }
    1411                 :          0 :                 spin_unlock_irq(&callback_lock);
    1412                 :            : 
    1413   [ #  #  #  #  :          0 :                 WARN_ON(!is_in_v2_mode() &&
             #  #  #  # ]
    1414                 :            :                         !cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
    1415                 :            : 
    1416                 :          0 :                 update_tasks_cpumask(cp);
    1417                 :            : 
    1418                 :            :                 /*
    1419                 :            :                  * On legacy hierarchy, if the effective cpumask of any non-
    1420                 :            :                  * empty cpuset is changed, we need to rebuild sched domains.
    1421                 :            :                  * On default hierarchy, the cpuset needs to be a partition
    1422                 :            :                  * root as well.
    1423                 :            :                  */
    1424   [ #  #  #  # ]:          0 :                 if (!cpumask_empty(cp->cpus_allowed) &&
    1425                 :          0 :                     is_sched_load_balance(cp) &&
    1426   [ #  #  #  # ]:          0 :                    (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
    1427         [ #  # ]:          0 :                     is_partition_root(cp)))
    1428                 :            :                         need_rebuild_sched_domains = true;
    1429                 :            : 
    1430                 :          0 :                 rcu_read_lock();
    1431         [ #  # ]:          0 :                 css_put(&cp->css);
    1432                 :            :         }
    1433                 :          0 :         rcu_read_unlock();
    1434                 :            : 
    1435         [ #  # ]:          0 :         if (need_rebuild_sched_domains)
    1436                 :          0 :                 rebuild_sched_domains_locked();
    1437                 :          0 : }
    1438                 :            : 
    1439                 :            : /**
    1440                 :            :  * update_sibling_cpumasks - Update siblings cpumasks
    1441                 :            :  * @parent:  Parent cpuset
    1442                 :            :  * @cs:      Current cpuset
    1443                 :            :  * @tmp:     Temp variables
    1444                 :            :  */
    1445                 :          0 : static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
    1446                 :            :                                     struct tmpmasks *tmp)
    1447                 :            : {
    1448                 :          0 :         struct cpuset *sibling;
    1449                 :          0 :         struct cgroup_subsys_state *pos_css;
    1450                 :            : 
    1451                 :            :         /*
    1452                 :            :          * Check all its siblings and call update_cpumasks_hier()
    1453                 :            :          * if their use_parent_ecpus flag is set in order for them
    1454                 :            :          * to use the right effective_cpus value.
    1455                 :            :          */
    1456                 :          0 :         rcu_read_lock();
    1457   [ #  #  #  # ]:          0 :         cpuset_for_each_child(sibling, pos_css, parent) {
    1458         [ #  # ]:          0 :                 if (sibling == cs)
    1459                 :          0 :                         continue;
    1460         [ #  # ]:          0 :                 if (!sibling->use_parent_ecpus)
    1461                 :          0 :                         continue;
    1462                 :            : 
    1463                 :          0 :                 update_cpumasks_hier(sibling, tmp);
    1464                 :            :         }
    1465                 :          0 :         rcu_read_unlock();
    1466                 :          0 : }
    1467                 :            : 
    1468                 :            : /**
    1469                 :            :  * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
    1470                 :            :  * @cs: the cpuset to consider
    1471                 :            :  * @trialcs: trial cpuset
    1472                 :            :  * @buf: buffer of cpu numbers written to this cpuset
    1473                 :            :  */
    1474                 :          0 : static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
    1475                 :            :                           const char *buf)
    1476                 :            : {
    1477                 :          0 :         int retval;
    1478                 :          0 :         struct tmpmasks tmp;
    1479                 :            : 
    1480                 :            :         /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
    1481         [ #  # ]:          0 :         if (cs == &top_cpuset)
    1482                 :            :                 return -EACCES;
    1483                 :            : 
    1484                 :            :         /*
    1485                 :            :          * An empty cpus_allowed is ok only if the cpuset has no tasks.
    1486                 :            :          * Since cpulist_parse() fails on an empty mask, we special case
    1487                 :            :          * that parsing.  The validate_change() call ensures that cpusets
    1488                 :            :          * with tasks have cpus.
    1489                 :            :          */
    1490         [ #  # ]:          0 :         if (!*buf) {
    1491                 :          0 :                 cpumask_clear(trialcs->cpus_allowed);
    1492                 :            :         } else {
    1493                 :          0 :                 retval = cpulist_parse(buf, trialcs->cpus_allowed);
    1494         [ #  # ]:          0 :                 if (retval < 0)
    1495                 :            :                         return retval;
    1496                 :            : 
    1497         [ #  # ]:          0 :                 if (!cpumask_subset(trialcs->cpus_allowed,
    1498                 :            :                                     top_cpuset.cpus_allowed))
    1499                 :            :                         return -EINVAL;
    1500                 :            :         }
    1501                 :            : 
    1502                 :            :         /* Nothing to do if the cpus didn't change */
    1503         [ #  # ]:          0 :         if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
    1504                 :            :                 return 0;
    1505                 :            : 
    1506                 :          0 :         retval = validate_change(cs, trialcs);
    1507         [ #  # ]:          0 :         if (retval < 0)
    1508                 :            :                 return retval;
    1509                 :            : 
    1510                 :            : #ifdef CONFIG_CPUMASK_OFFSTACK
    1511                 :            :         /*
    1512                 :            :          * Use the cpumasks in trialcs for tmpmasks when they are pointers
    1513                 :            :          * to allocated cpumasks.
    1514                 :            :          */
    1515                 :            :         tmp.addmask  = trialcs->subparts_cpus;
    1516                 :            :         tmp.delmask  = trialcs->effective_cpus;
    1517                 :            :         tmp.new_cpus = trialcs->cpus_allowed;
    1518                 :            : #endif
    1519                 :            : 
    1520         [ #  # ]:          0 :         if (cs->partition_root_state) {
    1521                 :            :                 /* Cpumask of a partition root cannot be empty */
    1522         [ #  # ]:          0 :                 if (cpumask_empty(trialcs->cpus_allowed))
    1523                 :            :                         return -EINVAL;
    1524         [ #  # ]:          0 :                 if (update_parent_subparts_cpumask(cs, partcmd_update,
    1525                 :          0 :                                         trialcs->cpus_allowed, &tmp) < 0)
    1526                 :            :                         return -EINVAL;
    1527                 :            :         }
    1528                 :            : 
    1529                 :          0 :         spin_lock_irq(&callback_lock);
    1530         [ #  # ]:          0 :         cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
    1531                 :            : 
    1532                 :            :         /*
    1533                 :            :          * Make sure that subparts_cpus is a subset of cpus_allowed.
    1534                 :            :          */
    1535         [ #  # ]:          0 :         if (cs->nr_subparts_cpus) {
    1536                 :          0 :                 cpumask_andnot(cs->subparts_cpus, cs->subparts_cpus,
    1537                 :            :                                cs->cpus_allowed);
    1538                 :          0 :                 cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
    1539                 :            :         }
    1540                 :          0 :         spin_unlock_irq(&callback_lock);
    1541                 :            : 
    1542                 :          0 :         update_cpumasks_hier(cs, &tmp);
    1543                 :            : 
    1544         [ #  # ]:          0 :         if (cs->partition_root_state) {
    1545         [ #  # ]:          0 :                 struct cpuset *parent = parent_cs(cs);
    1546                 :            : 
    1547                 :            :                 /*
    1548                 :            :                  * For partition root, update the cpumasks of sibling
    1549                 :            :                  * cpusets if they use parent's effective_cpus.
    1550                 :            :                  */
    1551         [ #  # ]:          0 :                 if (parent->child_ecpus_count)
    1552                 :          0 :                         update_sibling_cpumasks(parent, cs, &tmp);
    1553                 :            :         }
    1554                 :            :         return 0;
    1555                 :            : }
    1556                 :            : 
    1557                 :            : /*
    1558                 :            :  * Migrate memory region from one set of nodes to another.  This is
    1559                 :            :  * performed asynchronously as it can be called from process migration path
    1560                 :            :  * holding locks involved in process management.  All mm migrations are
    1561                 :            :  * performed in the queued order and can be waited for by flushing
    1562                 :            :  * cpuset_migrate_mm_wq.
    1563                 :            :  */
    1564                 :            : 
    1565                 :            : struct cpuset_migrate_mm_work {
    1566                 :            :         struct work_struct      work;
    1567                 :            :         struct mm_struct        *mm;
    1568                 :            :         nodemask_t              from;
    1569                 :            :         nodemask_t              to;
    1570                 :            : };
    1571                 :            : 
    1572                 :          0 : static void cpuset_migrate_mm_workfn(struct work_struct *work)
    1573                 :            : {
    1574                 :          0 :         struct cpuset_migrate_mm_work *mwork =
    1575                 :          0 :                 container_of(work, struct cpuset_migrate_mm_work, work);
    1576                 :            : 
    1577                 :            :         /* on a wq worker, no need to worry about %current's mems_allowed */
    1578                 :          0 :         do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL);
    1579                 :          0 :         mmput(mwork->mm);
    1580                 :          0 :         kfree(mwork);
    1581                 :          0 : }
    1582                 :            : 
    1583                 :            : static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
    1584                 :            :                                                         const nodemask_t *to)
    1585                 :            : {
    1586                 :            :         struct cpuset_migrate_mm_work *mwork;
    1587                 :            : 
    1588                 :            :         mwork = kzalloc(sizeof(*mwork), GFP_KERNEL);
    1589                 :            :         if (mwork) {
    1590                 :            :                 mwork->mm = mm;
    1591                 :            :                 mwork->from = *from;
    1592                 :            :                 mwork->to = *to;
    1593                 :            :                 INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn);
    1594                 :            :                 queue_work(cpuset_migrate_mm_wq, &mwork->work);
    1595                 :            :         } else {
    1596                 :            :                 mmput(mm);
    1597                 :            :         }
    1598                 :            : }
    1599                 :            : 
    1600                 :       4290 : static void cpuset_post_attach(void)
    1601                 :            : {
    1602                 :       4290 :         flush_workqueue(cpuset_migrate_mm_wq);
    1603                 :       4290 : }
    1604                 :            : 
    1605                 :            : /*
    1606                 :            :  * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
    1607                 :            :  * @tsk: the task to change
    1608                 :            :  * @newmems: new nodes that the task will be set
    1609                 :            :  *
    1610                 :            :  * We use the mems_allowed_seq seqlock to safely update both tsk->mems_allowed
    1611                 :            :  * and rebind an eventual tasks' mempolicy. If the task is allocating in
    1612                 :            :  * parallel, it might temporarily see an empty intersection, which results in
    1613                 :            :  * a seqlock check and retry before OOM or allocation failure.
    1614                 :            :  */
    1615                 :          0 : static void cpuset_change_task_nodemask(struct task_struct *tsk,
    1616                 :            :                                         nodemask_t *newmems)
    1617                 :            : {
    1618                 :          0 :         task_lock(tsk);
    1619                 :            : 
    1620                 :          0 :         local_irq_disable();
    1621                 :          0 :         write_seqcount_begin(&tsk->mems_allowed_seq);
    1622                 :            : 
    1623                 :          0 :         nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
    1624                 :          0 :         mpol_rebind_task(tsk, newmems);
    1625                 :          0 :         tsk->mems_allowed = *newmems;
    1626                 :            : 
    1627                 :          0 :         write_seqcount_end(&tsk->mems_allowed_seq);
    1628                 :          0 :         local_irq_enable();
    1629                 :            : 
    1630                 :          0 :         task_unlock(tsk);
    1631                 :          0 : }
    1632                 :            : 
    1633                 :            : static void *cpuset_being_rebound;
    1634                 :            : 
    1635                 :            : /**
    1636                 :            :  * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
    1637                 :            :  * @cs: the cpuset in which each task's mems_allowed mask needs to be changed
    1638                 :            :  *
    1639                 :            :  * Iterate through each task of @cs updating its mems_allowed to the
    1640                 :            :  * effective cpuset's.  As this function is called with cpuset_mutex held,
    1641                 :            :  * cpuset membership stays stable.
    1642                 :            :  */
    1643                 :          0 : static void update_tasks_nodemask(struct cpuset *cs)
    1644                 :            : {
    1645                 :          0 :         static nodemask_t newmems;      /* protected by cpuset_mutex */
    1646                 :          0 :         struct css_task_iter it;
    1647                 :          0 :         struct task_struct *task;
    1648                 :            : 
    1649                 :          0 :         cpuset_being_rebound = cs;              /* causes mpol_dup() rebind */
    1650                 :            : 
    1651                 :          0 :         guarantee_online_mems(cs, &newmems);
    1652                 :            : 
    1653                 :            :         /*
    1654                 :            :          * The mpol_rebind_mm() call takes mmap_sem, which we couldn't
    1655                 :            :          * take while holding tasklist_lock.  Forks can happen - the
    1656                 :            :          * mpol_dup() cpuset_being_rebound check will catch such forks,
    1657                 :            :          * and rebind their vma mempolicies too.  Because we still hold
    1658                 :            :          * the global cpuset_mutex, we know that no other rebind effort
    1659                 :            :          * will be contending for the global variable cpuset_being_rebound.
    1660                 :            :          * It's ok if we rebind the same mm twice; mpol_rebind_mm()
    1661                 :            :          * is idempotent.  Also migrate pages in each mm to new nodes.
    1662                 :            :          */
    1663                 :          0 :         css_task_iter_start(&cs->css, 0, &it);
    1664         [ #  # ]:          0 :         while ((task = css_task_iter_next(&it))) {
    1665                 :          0 :                 struct mm_struct *mm;
    1666                 :          0 :                 bool migrate;
    1667                 :            : 
    1668                 :          0 :                 cpuset_change_task_nodemask(task, &newmems);
    1669                 :            : 
    1670                 :          0 :                 mm = get_task_mm(task);
    1671         [ #  # ]:          0 :                 if (!mm)
    1672                 :          0 :                         continue;
    1673                 :            : 
    1674                 :          0 :                 migrate = is_memory_migrate(cs);
    1675                 :            : 
    1676                 :          0 :                 mpol_rebind_mm(mm, &cs->mems_allowed);
    1677         [ #  # ]:          0 :                 if (migrate)
    1678                 :          0 :                         cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
    1679                 :            :                 else
    1680                 :          0 :                         mmput(mm);
    1681                 :            :         }
    1682                 :          0 :         css_task_iter_end(&it);
    1683                 :            : 
    1684                 :            :         /*
    1685                 :            :          * All the tasks' nodemasks have been updated, update
    1686                 :            :          * cs->old_mems_allowed.
    1687                 :            :          */
    1688                 :          0 :         cs->old_mems_allowed = newmems;
    1689                 :            : 
    1690                 :            :         /* We're done rebinding vmas to this cpuset's new mems_allowed. */
    1691                 :          0 :         cpuset_being_rebound = NULL;
    1692                 :          0 : }
    1693                 :            : 
    1694                 :            : /*
    1695                 :            :  * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree
    1696                 :            :  * @cs: the cpuset to consider
    1697                 :            :  * @new_mems: a temp variable for calculating new effective_mems
    1698                 :            :  *
    1699                 :            :  * When configured nodemask is changed, the effective nodemasks of this cpuset
    1700                 :            :  * and all its descendants need to be updated.
    1701                 :            :  *
    1702                 :            :  * On legacy hiearchy, effective_mems will be the same with mems_allowed.
    1703                 :            :  *
    1704                 :            :  * Called with cpuset_mutex held
    1705                 :            :  */
    1706                 :          0 : static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
    1707                 :            : {
    1708                 :          0 :         struct cpuset *cp;
    1709                 :          0 :         struct cgroup_subsys_state *pos_css;
    1710                 :            : 
    1711                 :          0 :         rcu_read_lock();
    1712   [ #  #  #  # ]:          0 :         cpuset_for_each_descendant_pre(cp, pos_css, cs) {
    1713         [ #  # ]:          0 :                 struct cpuset *parent = parent_cs(cp);
    1714                 :            : 
    1715                 :          0 :                 nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems);
    1716                 :            : 
    1717                 :            :                 /*
    1718                 :            :                  * If it becomes empty, inherit the effective mask of the
    1719                 :            :                  * parent, which is guaranteed to have some MEMs.
    1720                 :            :                  */
    1721   [ #  #  #  #  :          0 :                 if (is_in_v2_mode() && nodes_empty(*new_mems))
                   #  # ]
    1722                 :          0 :                         *new_mems = parent->effective_mems;
    1723                 :            : 
    1724                 :            :                 /* Skip the whole subtree if the nodemask remains the same. */
    1725         [ #  # ]:          0 :                 if (nodes_equal(*new_mems, cp->effective_mems)) {
    1726                 :          0 :                         pos_css = css_rightmost_descendant(pos_css);
    1727                 :          0 :                         continue;
    1728                 :            :                 }
    1729                 :            : 
    1730   [ #  #  #  # ]:          0 :                 if (!css_tryget_online(&cp->css))
    1731                 :          0 :                         continue;
    1732                 :          0 :                 rcu_read_unlock();
    1733                 :            : 
    1734                 :          0 :                 spin_lock_irq(&callback_lock);
    1735                 :          0 :                 cp->effective_mems = *new_mems;
    1736                 :          0 :                 spin_unlock_irq(&callback_lock);
    1737                 :            : 
    1738   [ #  #  #  #  :          0 :                 WARN_ON(!is_in_v2_mode() &&
             #  #  #  # ]
    1739                 :            :                         !nodes_equal(cp->mems_allowed, cp->effective_mems));
    1740                 :            : 
    1741                 :          0 :                 update_tasks_nodemask(cp);
    1742                 :            : 
    1743                 :          0 :                 rcu_read_lock();
    1744         [ #  # ]:          0 :                 css_put(&cp->css);
    1745                 :            :         }
    1746                 :          0 :         rcu_read_unlock();
    1747                 :          0 : }
    1748                 :            : 
    1749                 :            : /*
    1750                 :            :  * Handle user request to change the 'mems' memory placement
    1751                 :            :  * of a cpuset.  Needs to validate the request, update the
    1752                 :            :  * cpusets mems_allowed, and for each task in the cpuset,
    1753                 :            :  * update mems_allowed and rebind task's mempolicy and any vma
    1754                 :            :  * mempolicies and if the cpuset is marked 'memory_migrate',
    1755                 :            :  * migrate the tasks pages to the new memory.
    1756                 :            :  *
    1757                 :            :  * Call with cpuset_mutex held. May take callback_lock during call.
    1758                 :            :  * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
    1759                 :            :  * lock each such tasks mm->mmap_sem, scan its vma's and rebind
    1760                 :            :  * their mempolicies to the cpusets new mems_allowed.
    1761                 :            :  */
    1762                 :          0 : static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
    1763                 :            :                            const char *buf)
    1764                 :            : {
    1765                 :          0 :         int retval;
    1766                 :            : 
    1767                 :            :         /*
    1768                 :            :          * top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
    1769                 :            :          * it's read-only
    1770                 :            :          */
    1771         [ #  # ]:          0 :         if (cs == &top_cpuset) {
    1772                 :          0 :                 retval = -EACCES;
    1773                 :          0 :                 goto done;
    1774                 :            :         }
    1775                 :            : 
    1776                 :            :         /*
    1777                 :            :          * An empty mems_allowed is ok iff there are no tasks in the cpuset.
    1778                 :            :          * Since nodelist_parse() fails on an empty mask, we special case
    1779                 :            :          * that parsing.  The validate_change() call ensures that cpusets
    1780                 :            :          * with tasks have memory.
    1781                 :            :          */
    1782         [ #  # ]:          0 :         if (!*buf) {
    1783                 :          0 :                 nodes_clear(trialcs->mems_allowed);
    1784                 :            :         } else {
    1785                 :          0 :                 retval = nodelist_parse(buf, trialcs->mems_allowed);
    1786         [ #  # ]:          0 :                 if (retval < 0)
    1787                 :          0 :                         goto done;
    1788                 :            : 
    1789         [ #  # ]:          0 :                 if (!nodes_subset(trialcs->mems_allowed,
    1790                 :            :                                   top_cpuset.mems_allowed)) {
    1791                 :          0 :                         retval = -EINVAL;
    1792                 :          0 :                         goto done;
    1793                 :            :                 }
    1794                 :            :         }
    1795                 :            : 
    1796         [ #  # ]:          0 :         if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) {
    1797                 :          0 :                 retval = 0;             /* Too easy - nothing to do */
    1798                 :          0 :                 goto done;
    1799                 :            :         }
    1800                 :          0 :         retval = validate_change(cs, trialcs);
    1801         [ #  # ]:          0 :         if (retval < 0)
    1802                 :          0 :                 goto done;
    1803                 :            : 
    1804                 :          0 :         spin_lock_irq(&callback_lock);
    1805                 :          0 :         cs->mems_allowed = trialcs->mems_allowed;
    1806                 :          0 :         spin_unlock_irq(&callback_lock);
    1807                 :            : 
    1808                 :            :         /* use trialcs->mems_allowed as a temp variable */
    1809                 :          0 :         update_nodemasks_hier(cs, &trialcs->mems_allowed);
    1810                 :          0 : done:
    1811                 :          0 :         return retval;
    1812                 :            : }
    1813                 :            : 
    1814                 :         30 : bool current_cpuset_is_being_rebound(void)
    1815                 :            : {
    1816                 :         30 :         bool ret;
    1817                 :            : 
    1818                 :         30 :         rcu_read_lock();
    1819         [ -  + ]:         30 :         ret = task_cs(current) == cpuset_being_rebound;
    1820                 :         30 :         rcu_read_unlock();
    1821                 :            : 
    1822                 :         30 :         return ret;
    1823                 :            : }
    1824                 :            : 
    1825                 :          0 : static int update_relax_domain_level(struct cpuset *cs, s64 val)
    1826                 :            : {
    1827                 :            : #ifdef CONFIG_SMP
    1828   [ #  #  #  # ]:          0 :         if (val < -1 || val >= sched_domain_level_max)
    1829                 :            :                 return -EINVAL;
    1830                 :            : #endif
    1831                 :            : 
    1832         [ #  # ]:          0 :         if (val != cs->relax_domain_level) {
    1833                 :          0 :                 cs->relax_domain_level = val;
    1834   [ #  #  #  # ]:          0 :                 if (!cpumask_empty(cs->cpus_allowed) &&
    1835                 :            :                     is_sched_load_balance(cs))
    1836                 :          0 :                         rebuild_sched_domains_locked();
    1837                 :            :         }
    1838                 :            : 
    1839                 :            :         return 0;
    1840                 :            : }
    1841                 :            : 
    1842                 :            : /**
    1843                 :            :  * update_tasks_flags - update the spread flags of tasks in the cpuset.
    1844                 :            :  * @cs: the cpuset in which each task's spread flags needs to be changed
    1845                 :            :  *
    1846                 :            :  * Iterate through each task of @cs updating its spread flags.  As this
    1847                 :            :  * function is called with cpuset_mutex held, cpuset membership stays
    1848                 :            :  * stable.
    1849                 :            :  */
    1850                 :          0 : static void update_tasks_flags(struct cpuset *cs)
    1851                 :            : {
    1852                 :          0 :         struct css_task_iter it;
    1853                 :          0 :         struct task_struct *task;
    1854                 :            : 
    1855                 :          0 :         css_task_iter_start(&cs->css, 0, &it);
    1856         [ #  # ]:          0 :         while ((task = css_task_iter_next(&it)))
    1857                 :          0 :                 cpuset_update_task_spread_flag(cs, task);
    1858                 :          0 :         css_task_iter_end(&it);
    1859                 :          0 : }
    1860                 :            : 
    1861                 :            : /*
    1862                 :            :  * update_flag - read a 0 or a 1 in a file and update associated flag
    1863                 :            :  * bit:         the bit to update (see cpuset_flagbits_t)
    1864                 :            :  * cs:          the cpuset to update
    1865                 :            :  * turning_on:  whether the flag is being set or cleared
    1866                 :            :  *
    1867                 :            :  * Call with cpuset_mutex held.
    1868                 :            :  */
    1869                 :            : 
    1870                 :          0 : static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
    1871                 :            :                        int turning_on)
    1872                 :            : {
    1873                 :          0 :         struct cpuset *trialcs;
    1874                 :          0 :         int balance_flag_changed;
    1875                 :          0 :         int spread_flag_changed;
    1876                 :          0 :         int err;
    1877                 :            : 
    1878                 :          0 :         trialcs = alloc_trial_cpuset(cs);
    1879         [ #  # ]:          0 :         if (!trialcs)
    1880                 :            :                 return -ENOMEM;
    1881                 :            : 
    1882         [ #  # ]:          0 :         if (turning_on)
    1883                 :          0 :                 set_bit(bit, &trialcs->flags);
    1884                 :            :         else
    1885                 :          0 :                 clear_bit(bit, &trialcs->flags);
    1886                 :            : 
    1887                 :          0 :         err = validate_change(cs, trialcs);
    1888         [ #  # ]:          0 :         if (err < 0)
    1889                 :          0 :                 goto out;
    1890                 :            : 
    1891                 :          0 :         balance_flag_changed = (is_sched_load_balance(cs) !=
    1892                 :            :                                 is_sched_load_balance(trialcs));
    1893                 :            : 
    1894                 :          0 :         spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
    1895   [ #  #  #  # ]:          0 :                         || (is_spread_page(cs) != is_spread_page(trialcs)));
    1896                 :            : 
    1897                 :          0 :         spin_lock_irq(&callback_lock);
    1898                 :          0 :         cs->flags = trialcs->flags;
    1899                 :          0 :         spin_unlock_irq(&callback_lock);
    1900                 :            : 
    1901   [ #  #  #  # ]:          0 :         if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
    1902                 :          0 :                 rebuild_sched_domains_locked();
    1903                 :            : 
    1904         [ #  # ]:          0 :         if (spread_flag_changed)
    1905                 :          0 :                 update_tasks_flags(cs);
    1906                 :          0 : out:
    1907                 :          0 :         free_cpuset(trialcs);
    1908                 :          0 :         return err;
    1909                 :            : }
    1910                 :            : 
    1911                 :            : /*
    1912                 :            :  * update_prstate - update partititon_root_state
    1913                 :            :  * cs:  the cpuset to update
    1914                 :            :  * val: 0 - disabled, 1 - enabled
    1915                 :            :  *
    1916                 :            :  * Call with cpuset_mutex held.
    1917                 :            :  */
    1918                 :          0 : static int update_prstate(struct cpuset *cs, int val)
    1919                 :            : {
    1920                 :          0 :         int err;
    1921         [ #  # ]:          0 :         struct cpuset *parent = parent_cs(cs);
    1922                 :          0 :         struct tmpmasks tmp;
    1923                 :            : 
    1924         [ #  # ]:          0 :         if ((val != 0) && (val != 1))
    1925                 :            :                 return -EINVAL;
    1926         [ #  # ]:          0 :         if (val == cs->partition_root_state)
    1927                 :            :                 return 0;
    1928                 :            : 
    1929                 :            :         /*
    1930                 :            :          * Cannot force a partial or invalid partition root to a full
    1931                 :            :          * partition root.
    1932                 :            :          */
    1933   [ #  #  #  # ]:          0 :         if (val && cs->partition_root_state)
    1934                 :            :                 return -EINVAL;
    1935                 :            : 
    1936         [ #  # ]:          0 :         if (alloc_cpumasks(NULL, &tmp))
    1937                 :            :                 return -ENOMEM;
    1938                 :            : 
    1939                 :          0 :         err = -EINVAL;
    1940         [ #  # ]:          0 :         if (!cs->partition_root_state) {
    1941                 :            :                 /*
    1942                 :            :                  * Turning on partition root requires setting the
    1943                 :            :                  * CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed
    1944                 :            :                  * cannot be NULL.
    1945                 :            :                  */
    1946         [ #  # ]:          0 :                 if (cpumask_empty(cs->cpus_allowed))
    1947                 :          0 :                         goto out;
    1948                 :            : 
    1949                 :          0 :                 err = update_flag(CS_CPU_EXCLUSIVE, cs, 1);
    1950         [ #  # ]:          0 :                 if (err)
    1951                 :          0 :                         goto out;
    1952                 :            : 
    1953                 :          0 :                 err = update_parent_subparts_cpumask(cs, partcmd_enable,
    1954                 :            :                                                      NULL, &tmp);
    1955         [ #  # ]:          0 :                 if (err) {
    1956                 :          0 :                         update_flag(CS_CPU_EXCLUSIVE, cs, 0);
    1957                 :          0 :                         goto out;
    1958                 :            :                 }
    1959                 :          0 :                 cs->partition_root_state = PRS_ENABLED;
    1960                 :            :         } else {
    1961                 :            :                 /*
    1962                 :            :                  * Turning off partition root will clear the
    1963                 :            :                  * CS_CPU_EXCLUSIVE bit.
    1964                 :            :                  */
    1965         [ #  # ]:          0 :                 if (cs->partition_root_state == PRS_ERROR) {
    1966                 :          0 :                         cs->partition_root_state = 0;
    1967                 :          0 :                         update_flag(CS_CPU_EXCLUSIVE, cs, 0);
    1968                 :          0 :                         err = 0;
    1969                 :          0 :                         goto out;
    1970                 :            :                 }
    1971                 :            : 
    1972                 :          0 :                 err = update_parent_subparts_cpumask(cs, partcmd_disable,
    1973                 :            :                                                      NULL, &tmp);
    1974         [ #  # ]:          0 :                 if (err)
    1975                 :          0 :                         goto out;
    1976                 :            : 
    1977                 :          0 :                 cs->partition_root_state = 0;
    1978                 :            : 
    1979                 :            :                 /* Turning off CS_CPU_EXCLUSIVE will not return error */
    1980                 :          0 :                 update_flag(CS_CPU_EXCLUSIVE, cs, 0);
    1981                 :            :         }
    1982                 :            : 
    1983                 :            :         /*
    1984                 :            :          * Update cpumask of parent's tasks except when it is the top
    1985                 :            :          * cpuset as some system daemons cannot be mapped to other CPUs.
    1986                 :            :          */
    1987         [ #  # ]:          0 :         if (parent != &top_cpuset)
    1988                 :          0 :                 update_tasks_cpumask(parent);
    1989                 :            : 
    1990         [ #  # ]:          0 :         if (parent->child_ecpus_count)
    1991                 :          0 :                 update_sibling_cpumasks(parent, cs, &tmp);
    1992                 :            : 
    1993                 :          0 :         rebuild_sched_domains_locked();
    1994                 :            : out:
    1995                 :            :         free_cpumasks(NULL, &tmp);
    1996                 :            :         return err;
    1997                 :            : }
    1998                 :            : 
    1999                 :            : /*
    2000                 :            :  * Frequency meter - How fast is some event occurring?
    2001                 :            :  *
    2002                 :            :  * These routines manage a digitally filtered, constant time based,
    2003                 :            :  * event frequency meter.  There are four routines:
    2004                 :            :  *   fmeter_init() - initialize a frequency meter.
    2005                 :            :  *   fmeter_markevent() - called each time the event happens.
    2006                 :            :  *   fmeter_getrate() - returns the recent rate of such events.
    2007                 :            :  *   fmeter_update() - internal routine used to update fmeter.
    2008                 :            :  *
    2009                 :            :  * A common data structure is passed to each of these routines,
    2010                 :            :  * which is used to keep track of the state required to manage the
    2011                 :            :  * frequency meter and its digital filter.
    2012                 :            :  *
    2013                 :            :  * The filter works on the number of events marked per unit time.
    2014                 :            :  * The filter is single-pole low-pass recursive (IIR).  The time unit
    2015                 :            :  * is 1 second.  Arithmetic is done using 32-bit integers scaled to
    2016                 :            :  * simulate 3 decimal digits of precision (multiplied by 1000).
    2017                 :            :  *
    2018                 :            :  * With an FM_COEF of 933, and a time base of 1 second, the filter
    2019                 :            :  * has a half-life of 10 seconds, meaning that if the events quit
    2020                 :            :  * happening, then the rate returned from the fmeter_getrate()
    2021                 :            :  * will be cut in half each 10 seconds, until it converges to zero.
    2022                 :            :  *
    2023                 :            :  * It is not worth doing a real infinitely recursive filter.  If more
    2024                 :            :  * than FM_MAXTICKS ticks have elapsed since the last filter event,
    2025                 :            :  * just compute FM_MAXTICKS ticks worth, by which point the level
    2026                 :            :  * will be stable.
    2027                 :            :  *
    2028                 :            :  * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
    2029                 :            :  * arithmetic overflow in the fmeter_update() routine.
    2030                 :            :  *
    2031                 :            :  * Given the simple 32 bit integer arithmetic used, this meter works
    2032                 :            :  * best for reporting rates between one per millisecond (msec) and
    2033                 :            :  * one per 32 (approx) seconds.  At constant rates faster than one
    2034                 :            :  * per msec it maxes out at values just under 1,000,000.  At constant
    2035                 :            :  * rates between one per msec, and one per second it will stabilize
    2036                 :            :  * to a value N*1000, where N is the rate of events per second.
    2037                 :            :  * At constant rates between one per second and one per 32 seconds,
    2038                 :            :  * it will be choppy, moving up on the seconds that have an event,
    2039                 :            :  * and then decaying until the next event.  At rates slower than
    2040                 :            :  * about one in 32 seconds, it decays all the way back to zero between
    2041                 :            :  * each event.
    2042                 :            :  */
    2043                 :            : 
    2044                 :            : #define FM_COEF 933             /* coefficient for half-life of 10 secs */
    2045                 :            : #define FM_MAXTICKS ((u32)99)   /* useless computing more ticks than this */
    2046                 :            : #define FM_MAXCNT 1000000       /* limit cnt to avoid overflow */
    2047                 :            : #define FM_SCALE 1000           /* faux fixed point scale */
    2048                 :            : 
    2049                 :            : /* Initialize a frequency meter */
    2050                 :         30 : static void fmeter_init(struct fmeter *fmp)
    2051                 :            : {
    2052                 :         30 :         fmp->cnt = 0;
    2053                 :         30 :         fmp->val = 0;
    2054                 :         30 :         fmp->time = 0;
    2055                 :         30 :         spin_lock_init(&fmp->lock);
    2056                 :            : }
    2057                 :            : 
    2058                 :            : /* Internal meter update - process cnt events and update value */
    2059                 :          0 : static void fmeter_update(struct fmeter *fmp)
    2060                 :            : {
    2061                 :          0 :         time64_t now;
    2062                 :          0 :         u32 ticks;
    2063                 :            : 
    2064                 :          0 :         now = ktime_get_seconds();
    2065                 :          0 :         ticks = now - fmp->time;
    2066                 :            : 
    2067         [ #  # ]:          0 :         if (ticks == 0)
    2068                 :            :                 return;
    2069                 :            : 
    2070                 :          0 :         ticks = min(FM_MAXTICKS, ticks);
    2071         [ #  # ]:          0 :         while (ticks-- > 0)
    2072                 :          0 :                 fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
    2073                 :          0 :         fmp->time = now;
    2074                 :            : 
    2075                 :          0 :         fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
    2076                 :          0 :         fmp->cnt = 0;
    2077                 :            : }
    2078                 :            : 
    2079                 :            : /* Process any previous ticks, then bump cnt by one (times scale). */
    2080                 :          0 : static void fmeter_markevent(struct fmeter *fmp)
    2081                 :            : {
    2082                 :          0 :         spin_lock(&fmp->lock);
    2083                 :          0 :         fmeter_update(fmp);
    2084                 :          0 :         fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
    2085                 :          0 :         spin_unlock(&fmp->lock);
    2086                 :          0 : }
    2087                 :            : 
    2088                 :            : /* Process any previous ticks, then return current value. */
    2089                 :          0 : static int fmeter_getrate(struct fmeter *fmp)
    2090                 :            : {
    2091                 :          0 :         int val;
    2092                 :            : 
    2093                 :          0 :         spin_lock(&fmp->lock);
    2094                 :          0 :         fmeter_update(fmp);
    2095                 :          0 :         val = fmp->val;
    2096                 :          0 :         spin_unlock(&fmp->lock);
    2097                 :          0 :         return val;
    2098                 :            : }
    2099                 :            : 
    2100                 :            : static struct cpuset *cpuset_attach_old_cs;
    2101                 :            : 
    2102                 :            : /* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */
    2103                 :          0 : static int cpuset_can_attach(struct cgroup_taskset *tset)
    2104                 :            : {
    2105                 :          0 :         struct cgroup_subsys_state *css;
    2106                 :          0 :         struct cpuset *cs;
    2107                 :          0 :         struct task_struct *task;
    2108                 :          0 :         int ret;
    2109                 :            : 
    2110                 :            :         /* used later by cpuset_attach() */
    2111                 :          0 :         cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css));
    2112         [ #  # ]:          0 :         cs = css_cs(css);
    2113                 :            : 
    2114                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2115                 :            : 
    2116                 :            :         /* allow moving tasks into an empty cpuset if on default hierarchy */
    2117                 :          0 :         ret = -ENOSPC;
    2118   [ #  #  #  #  :          0 :         if (!is_in_v2_mode() &&
                   #  # ]
    2119         [ #  # ]:          0 :             (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
    2120                 :          0 :                 goto out_unlock;
    2121                 :            : 
    2122         [ #  # ]:          0 :         cgroup_taskset_for_each(task, css, tset) {
    2123                 :          0 :                 ret = task_can_attach(task, cs->cpus_allowed);
    2124         [ #  # ]:          0 :                 if (ret)
    2125                 :          0 :                         goto out_unlock;
    2126                 :          0 :                 ret = security_task_setscheduler(task);
    2127         [ #  # ]:          0 :                 if (ret)
    2128                 :          0 :                         goto out_unlock;
    2129                 :            :         }
    2130                 :            : 
    2131                 :            :         /*
    2132                 :            :          * Mark attach is in progress.  This makes validate_change() fail
    2133                 :            :          * changes which zero cpus/mems_allowed.
    2134                 :            :          */
    2135                 :          0 :         cs->attach_in_progress++;
    2136                 :          0 :         ret = 0;
    2137                 :          0 : out_unlock:
    2138                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2139                 :          0 :         return ret;
    2140                 :            : }
    2141                 :            : 
    2142                 :          0 : static void cpuset_cancel_attach(struct cgroup_taskset *tset)
    2143                 :            : {
    2144                 :          0 :         struct cgroup_subsys_state *css;
    2145                 :            : 
    2146                 :          0 :         cgroup_taskset_first(tset, &css);
    2147                 :            : 
    2148                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2149         [ #  # ]:          0 :         css_cs(css)->attach_in_progress--;
    2150                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2151                 :          0 : }
    2152                 :            : 
    2153                 :            : /*
    2154                 :            :  * Protected by cpuset_mutex.  cpus_attach is used only by cpuset_attach()
    2155                 :            :  * but we can't allocate it dynamically there.  Define it global and
    2156                 :            :  * allocate from cpuset_init().
    2157                 :            :  */
    2158                 :            : static cpumask_var_t cpus_attach;
    2159                 :            : 
    2160                 :          0 : static void cpuset_attach(struct cgroup_taskset *tset)
    2161                 :            : {
    2162                 :            :         /* static buf protected by cpuset_mutex */
    2163                 :          0 :         static nodemask_t cpuset_attach_nodemask_to;
    2164                 :          0 :         struct task_struct *task;
    2165                 :          0 :         struct task_struct *leader;
    2166                 :          0 :         struct cgroup_subsys_state *css;
    2167                 :          0 :         struct cpuset *cs;
    2168                 :          0 :         struct cpuset *oldcs = cpuset_attach_old_cs;
    2169                 :            : 
    2170                 :          0 :         cgroup_taskset_first(tset, &css);
    2171         [ #  # ]:          0 :         cs = css_cs(css);
    2172                 :            : 
    2173                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2174                 :            : 
    2175                 :            :         /* prepare for attach */
    2176         [ #  # ]:          0 :         if (cs == &top_cpuset)
    2177                 :          0 :                 cpumask_copy(cpus_attach, cpu_possible_mask);
    2178                 :            :         else
    2179                 :            :                 guarantee_online_cpus(cs, cpus_attach);
    2180                 :            : 
    2181                 :          0 :         guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
    2182                 :            : 
    2183         [ #  # ]:          0 :         cgroup_taskset_for_each(task, css, tset) {
    2184                 :            :                 /*
    2185                 :            :                  * can_attach beforehand should guarantee that this doesn't
    2186                 :            :                  * fail.  TODO: have a better way to handle failure here
    2187                 :            :                  */
    2188         [ #  # ]:          0 :                 WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach));
    2189                 :            : 
    2190                 :          0 :                 cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);
    2191                 :          0 :                 cpuset_update_task_spread_flag(cs, task);
    2192                 :            :         }
    2193                 :            : 
    2194                 :            :         /*
    2195                 :            :          * Change mm for all threadgroup leaders. This is expensive and may
    2196                 :            :          * sleep and should be moved outside migration path proper.
    2197                 :            :          */
    2198                 :          0 :         cpuset_attach_nodemask_to = cs->effective_mems;
    2199   [ #  #  #  # ]:          0 :         cgroup_taskset_for_each_leader(leader, css, tset) {
    2200                 :          0 :                 struct mm_struct *mm = get_task_mm(leader);
    2201                 :            : 
    2202         [ #  # ]:          0 :                 if (mm) {
    2203                 :          0 :                         mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
    2204                 :            : 
    2205                 :            :                         /*
    2206                 :            :                          * old_mems_allowed is the same with mems_allowed
    2207                 :            :                          * here, except if this task is being moved
    2208                 :            :                          * automatically due to hotplug.  In that case
    2209                 :            :                          * @mems_allowed has been updated and is empty, so
    2210                 :            :                          * @old_mems_allowed is the right nodesets that we
    2211                 :            :                          * migrate mm from.
    2212                 :            :                          */
    2213         [ #  # ]:          0 :                         if (is_memory_migrate(cs))
    2214                 :          0 :                                 cpuset_migrate_mm(mm, &oldcs->old_mems_allowed,
    2215                 :            :                                                   &cpuset_attach_nodemask_to);
    2216                 :            :                         else
    2217                 :          0 :                                 mmput(mm);
    2218                 :            :                 }
    2219                 :            :         }
    2220                 :            : 
    2221                 :          0 :         cs->old_mems_allowed = cpuset_attach_nodemask_to;
    2222                 :            : 
    2223                 :          0 :         cs->attach_in_progress--;
    2224         [ #  # ]:          0 :         if (!cs->attach_in_progress)
    2225                 :          0 :                 wake_up(&cpuset_attach_wq);
    2226                 :            : 
    2227                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2228                 :          0 : }
    2229                 :            : 
    2230                 :            : /* The various types of files and directories in a cpuset file system */
    2231                 :            : 
    2232                 :            : typedef enum {
    2233                 :            :         FILE_MEMORY_MIGRATE,
    2234                 :            :         FILE_CPULIST,
    2235                 :            :         FILE_MEMLIST,
    2236                 :            :         FILE_EFFECTIVE_CPULIST,
    2237                 :            :         FILE_EFFECTIVE_MEMLIST,
    2238                 :            :         FILE_SUBPARTS_CPULIST,
    2239                 :            :         FILE_CPU_EXCLUSIVE,
    2240                 :            :         FILE_MEM_EXCLUSIVE,
    2241                 :            :         FILE_MEM_HARDWALL,
    2242                 :            :         FILE_SCHED_LOAD_BALANCE,
    2243                 :            :         FILE_PARTITION_ROOT,
    2244                 :            :         FILE_SCHED_RELAX_DOMAIN_LEVEL,
    2245                 :            :         FILE_MEMORY_PRESSURE_ENABLED,
    2246                 :            :         FILE_MEMORY_PRESSURE,
    2247                 :            :         FILE_SPREAD_PAGE,
    2248                 :            :         FILE_SPREAD_SLAB,
    2249                 :            : } cpuset_filetype_t;
    2250                 :            : 
    2251                 :          0 : static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
    2252                 :            :                             u64 val)
    2253                 :            : {
    2254         [ #  # ]:          0 :         struct cpuset *cs = css_cs(css);
    2255                 :          0 :         cpuset_filetype_t type = cft->private;
    2256                 :          0 :         int retval = 0;
    2257                 :            : 
    2258                 :          0 :         get_online_cpus();
    2259                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2260         [ #  # ]:          0 :         if (!is_cpuset_online(cs)) {
    2261                 :          0 :                 retval = -ENODEV;
    2262                 :          0 :                 goto out_unlock;
    2263                 :            :         }
    2264                 :            : 
    2265   [ #  #  #  #  :          0 :         switch (type) {
             #  #  #  #  
                      # ]
    2266                 :          0 :         case FILE_CPU_EXCLUSIVE:
    2267                 :          0 :                 retval = update_flag(CS_CPU_EXCLUSIVE, cs, val);
    2268                 :          0 :                 break;
    2269                 :          0 :         case FILE_MEM_EXCLUSIVE:
    2270                 :          0 :                 retval = update_flag(CS_MEM_EXCLUSIVE, cs, val);
    2271                 :          0 :                 break;
    2272                 :          0 :         case FILE_MEM_HARDWALL:
    2273                 :          0 :                 retval = update_flag(CS_MEM_HARDWALL, cs, val);
    2274                 :          0 :                 break;
    2275                 :          0 :         case FILE_SCHED_LOAD_BALANCE:
    2276                 :          0 :                 retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val);
    2277                 :          0 :                 break;
    2278                 :          0 :         case FILE_MEMORY_MIGRATE:
    2279                 :          0 :                 retval = update_flag(CS_MEMORY_MIGRATE, cs, val);
    2280                 :          0 :                 break;
    2281                 :          0 :         case FILE_MEMORY_PRESSURE_ENABLED:
    2282                 :          0 :                 cpuset_memory_pressure_enabled = !!val;
    2283                 :          0 :                 break;
    2284                 :          0 :         case FILE_SPREAD_PAGE:
    2285                 :          0 :                 retval = update_flag(CS_SPREAD_PAGE, cs, val);
    2286                 :          0 :                 break;
    2287                 :          0 :         case FILE_SPREAD_SLAB:
    2288                 :          0 :                 retval = update_flag(CS_SPREAD_SLAB, cs, val);
    2289                 :          0 :                 break;
    2290                 :            :         default:
    2291                 :            :                 retval = -EINVAL;
    2292                 :            :                 break;
    2293                 :            :         }
    2294                 :          0 : out_unlock:
    2295                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2296                 :          0 :         put_online_cpus();
    2297                 :          0 :         return retval;
    2298                 :            : }
    2299                 :            : 
    2300                 :          0 : static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
    2301                 :            :                             s64 val)
    2302                 :            : {
    2303         [ #  # ]:          0 :         struct cpuset *cs = css_cs(css);
    2304                 :          0 :         cpuset_filetype_t type = cft->private;
    2305                 :          0 :         int retval = -ENODEV;
    2306                 :            : 
    2307                 :          0 :         get_online_cpus();
    2308                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2309         [ #  # ]:          0 :         if (!is_cpuset_online(cs))
    2310                 :          0 :                 goto out_unlock;
    2311                 :            : 
    2312         [ #  # ]:          0 :         switch (type) {
    2313                 :          0 :         case FILE_SCHED_RELAX_DOMAIN_LEVEL:
    2314                 :          0 :                 retval = update_relax_domain_level(cs, val);
    2315                 :          0 :                 break;
    2316                 :            :         default:
    2317                 :            :                 retval = -EINVAL;
    2318                 :            :                 break;
    2319                 :            :         }
    2320                 :          0 : out_unlock:
    2321                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2322                 :          0 :         put_online_cpus();
    2323                 :          0 :         return retval;
    2324                 :            : }
    2325                 :            : 
    2326                 :            : /*
    2327                 :            :  * Common handling for a write to a "cpus" or "mems" file.
    2328                 :            :  */
    2329                 :          0 : static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
    2330                 :            :                                     char *buf, size_t nbytes, loff_t off)
    2331                 :            : {
    2332                 :          0 :         struct cpuset *cs = css_cs(of_css(of));
    2333                 :          0 :         struct cpuset *trialcs;
    2334                 :          0 :         int retval = -ENODEV;
    2335                 :            : 
    2336                 :          0 :         buf = strstrip(buf);
    2337                 :            : 
    2338                 :            :         /*
    2339                 :            :          * CPU or memory hotunplug may leave @cs w/o any execution
    2340                 :            :          * resources, in which case the hotplug code asynchronously updates
    2341                 :            :          * configuration and transfers all tasks to the nearest ancestor
    2342                 :            :          * which can execute.
    2343                 :            :          *
    2344                 :            :          * As writes to "cpus" or "mems" may restore @cs's execution
    2345                 :            :          * resources, wait for the previously scheduled operations before
    2346                 :            :          * proceeding, so that we don't end up keep removing tasks added
    2347                 :            :          * after execution capability is restored.
    2348                 :            :          *
    2349                 :            :          * cpuset_hotplug_work calls back into cgroup core via
    2350                 :            :          * cgroup_transfer_tasks() and waiting for it from a cgroupfs
    2351                 :            :          * operation like this one can lead to a deadlock through kernfs
    2352                 :            :          * active_ref protection.  Let's break the protection.  Losing the
    2353                 :            :          * protection is okay as we check whether @cs is online after
    2354                 :            :          * grabbing cpuset_mutex anyway.  This only happens on the legacy
    2355                 :            :          * hierarchies.
    2356                 :            :          */
    2357         [ #  # ]:          0 :         css_get(&cs->css);
    2358                 :          0 :         kernfs_break_active_protection(of->kn);
    2359                 :          0 :         flush_work(&cpuset_hotplug_work);
    2360                 :            : 
    2361                 :          0 :         get_online_cpus();
    2362                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2363         [ #  # ]:          0 :         if (!is_cpuset_online(cs))
    2364                 :          0 :                 goto out_unlock;
    2365                 :            : 
    2366                 :          0 :         trialcs = alloc_trial_cpuset(cs);
    2367         [ #  # ]:          0 :         if (!trialcs) {
    2368                 :          0 :                 retval = -ENOMEM;
    2369                 :          0 :                 goto out_unlock;
    2370                 :            :         }
    2371                 :            : 
    2372      [ #  #  # ]:          0 :         switch (of_cft(of)->private) {
    2373                 :          0 :         case FILE_CPULIST:
    2374                 :          0 :                 retval = update_cpumask(cs, trialcs, buf);
    2375                 :          0 :                 break;
    2376                 :          0 :         case FILE_MEMLIST:
    2377                 :          0 :                 retval = update_nodemask(cs, trialcs, buf);
    2378                 :          0 :                 break;
    2379                 :            :         default:
    2380                 :            :                 retval = -EINVAL;
    2381                 :            :                 break;
    2382                 :            :         }
    2383                 :            : 
    2384                 :          0 :         free_cpuset(trialcs);
    2385                 :          0 : out_unlock:
    2386                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2387                 :          0 :         put_online_cpus();
    2388                 :          0 :         kernfs_unbreak_active_protection(of->kn);
    2389         [ #  # ]:          0 :         css_put(&cs->css);
    2390                 :          0 :         flush_workqueue(cpuset_migrate_mm_wq);
    2391         [ #  # ]:          0 :         return retval ?: nbytes;
    2392                 :            : }
    2393                 :            : 
    2394                 :            : /*
    2395                 :            :  * These ascii lists should be read in a single call, by using a user
    2396                 :            :  * buffer large enough to hold the entire map.  If read in smaller
    2397                 :            :  * chunks, there is no guarantee of atomicity.  Since the display format
    2398                 :            :  * used, list of ranges of sequential numbers, is variable length,
    2399                 :            :  * and since these maps can change value dynamically, one could read
    2400                 :            :  * gibberish by doing partial reads while a list was changing.
    2401                 :            :  */
    2402                 :          0 : static int cpuset_common_seq_show(struct seq_file *sf, void *v)
    2403                 :            : {
    2404                 :          0 :         struct cpuset *cs = css_cs(seq_css(sf));
    2405                 :          0 :         cpuset_filetype_t type = seq_cft(sf)->private;
    2406                 :          0 :         int ret = 0;
    2407                 :            : 
    2408                 :          0 :         spin_lock_irq(&callback_lock);
    2409                 :            : 
    2410   [ #  #  #  #  :          0 :         switch (type) {
                   #  # ]
    2411                 :          0 :         case FILE_CPULIST:
    2412                 :          0 :                 seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_allowed));
    2413                 :          0 :                 break;
    2414                 :          0 :         case FILE_MEMLIST:
    2415         [ #  # ]:          0 :                 seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed));
    2416                 :          0 :                 break;
    2417                 :          0 :         case FILE_EFFECTIVE_CPULIST:
    2418                 :          0 :                 seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus));
    2419                 :          0 :                 break;
    2420                 :          0 :         case FILE_EFFECTIVE_MEMLIST:
    2421         [ #  # ]:          0 :                 seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems));
    2422                 :          0 :                 break;
    2423                 :          0 :         case FILE_SUBPARTS_CPULIST:
    2424                 :          0 :                 seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->subparts_cpus));
    2425                 :          0 :                 break;
    2426                 :            :         default:
    2427                 :            :                 ret = -EINVAL;
    2428                 :            :         }
    2429                 :            : 
    2430                 :          0 :         spin_unlock_irq(&callback_lock);
    2431                 :          0 :         return ret;
    2432                 :            : }
    2433                 :            : 
    2434                 :          0 : static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
    2435                 :            : {
    2436         [ #  # ]:          0 :         struct cpuset *cs = css_cs(css);
    2437                 :          0 :         cpuset_filetype_t type = cft->private;
    2438   [ #  #  #  #  :          0 :         switch (type) {
          #  #  #  #  #  
                      # ]
    2439                 :            :         case FILE_CPU_EXCLUSIVE:
    2440                 :          0 :                 return is_cpu_exclusive(cs);
    2441                 :            :         case FILE_MEM_EXCLUSIVE:
    2442                 :          0 :                 return is_mem_exclusive(cs);
    2443                 :            :         case FILE_MEM_HARDWALL:
    2444                 :          0 :                 return is_mem_hardwall(cs);
    2445                 :            :         case FILE_SCHED_LOAD_BALANCE:
    2446                 :          0 :                 return is_sched_load_balance(cs);
    2447                 :            :         case FILE_MEMORY_MIGRATE:
    2448                 :          0 :                 return is_memory_migrate(cs);
    2449                 :          0 :         case FILE_MEMORY_PRESSURE_ENABLED:
    2450                 :          0 :                 return cpuset_memory_pressure_enabled;
    2451                 :          0 :         case FILE_MEMORY_PRESSURE:
    2452                 :          0 :                 return fmeter_getrate(&cs->fmeter);
    2453                 :            :         case FILE_SPREAD_PAGE:
    2454                 :          0 :                 return is_spread_page(cs);
    2455                 :            :         case FILE_SPREAD_SLAB:
    2456                 :          0 :                 return is_spread_slab(cs);
    2457                 :          0 :         default:
    2458                 :          0 :                 BUG();
    2459                 :            :         }
    2460                 :            : 
    2461                 :            :         /* Unreachable but makes gcc happy */
    2462                 :            :         return 0;
    2463                 :            : }
    2464                 :            : 
    2465                 :          0 : static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
    2466                 :            : {
    2467         [ #  # ]:          0 :         struct cpuset *cs = css_cs(css);
    2468                 :          0 :         cpuset_filetype_t type = cft->private;
    2469         [ #  # ]:          0 :         switch (type) {
    2470                 :          0 :         case FILE_SCHED_RELAX_DOMAIN_LEVEL:
    2471                 :          0 :                 return cs->relax_domain_level;
    2472                 :          0 :         default:
    2473                 :          0 :                 BUG();
    2474                 :            :         }
    2475                 :            : 
    2476                 :            :         /* Unrechable but makes gcc happy */
    2477                 :            :         return 0;
    2478                 :            : }
    2479                 :            : 
    2480                 :          0 : static int sched_partition_show(struct seq_file *seq, void *v)
    2481                 :            : {
    2482                 :          0 :         struct cpuset *cs = css_cs(seq_css(seq));
    2483                 :            : 
    2484   [ #  #  #  # ]:          0 :         switch (cs->partition_root_state) {
    2485                 :          0 :         case PRS_ENABLED:
    2486                 :          0 :                 seq_puts(seq, "root\n");
    2487                 :          0 :                 break;
    2488                 :          0 :         case PRS_DISABLED:
    2489                 :          0 :                 seq_puts(seq, "member\n");
    2490                 :          0 :                 break;
    2491                 :          0 :         case PRS_ERROR:
    2492                 :          0 :                 seq_puts(seq, "root invalid\n");
    2493                 :          0 :                 break;
    2494                 :            :         }
    2495                 :          0 :         return 0;
    2496                 :            : }
    2497                 :            : 
    2498                 :          0 : static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
    2499                 :            :                                      size_t nbytes, loff_t off)
    2500                 :            : {
    2501                 :          0 :         struct cpuset *cs = css_cs(of_css(of));
    2502                 :          0 :         int val;
    2503                 :          0 :         int retval = -ENODEV;
    2504                 :            : 
    2505                 :          0 :         buf = strstrip(buf);
    2506                 :            : 
    2507                 :            :         /*
    2508                 :            :          * Convert "root" to ENABLED, and convert "member" to DISABLED.
    2509                 :            :          */
    2510         [ #  # ]:          0 :         if (!strcmp(buf, "root"))
    2511                 :            :                 val = PRS_ENABLED;
    2512         [ #  # ]:          0 :         else if (!strcmp(buf, "member"))
    2513                 :            :                 val = PRS_DISABLED;
    2514                 :            :         else
    2515                 :            :                 return -EINVAL;
    2516                 :            : 
    2517         [ #  # ]:          0 :         css_get(&cs->css);
    2518                 :          0 :         get_online_cpus();
    2519                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2520         [ #  # ]:          0 :         if (!is_cpuset_online(cs))
    2521                 :          0 :                 goto out_unlock;
    2522                 :            : 
    2523                 :          0 :         retval = update_prstate(cs, val);
    2524                 :          0 : out_unlock:
    2525                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2526                 :          0 :         put_online_cpus();
    2527         [ #  # ]:          0 :         css_put(&cs->css);
    2528         [ #  # ]:          0 :         return retval ?: nbytes;
    2529                 :            : }
    2530                 :            : 
    2531                 :            : /*
    2532                 :            :  * for the common functions, 'private' gives the type of file
    2533                 :            :  */
    2534                 :            : 
    2535                 :            : static struct cftype legacy_files[] = {
    2536                 :            :         {
    2537                 :            :                 .name = "cpus",
    2538                 :            :                 .seq_show = cpuset_common_seq_show,
    2539                 :            :                 .write = cpuset_write_resmask,
    2540                 :            :                 .max_write_len = (100U + 6 * NR_CPUS),
    2541                 :            :                 .private = FILE_CPULIST,
    2542                 :            :         },
    2543                 :            : 
    2544                 :            :         {
    2545                 :            :                 .name = "mems",
    2546                 :            :                 .seq_show = cpuset_common_seq_show,
    2547                 :            :                 .write = cpuset_write_resmask,
    2548                 :            :                 .max_write_len = (100U + 6 * MAX_NUMNODES),
    2549                 :            :                 .private = FILE_MEMLIST,
    2550                 :            :         },
    2551                 :            : 
    2552                 :            :         {
    2553                 :            :                 .name = "effective_cpus",
    2554                 :            :                 .seq_show = cpuset_common_seq_show,
    2555                 :            :                 .private = FILE_EFFECTIVE_CPULIST,
    2556                 :            :         },
    2557                 :            : 
    2558                 :            :         {
    2559                 :            :                 .name = "effective_mems",
    2560                 :            :                 .seq_show = cpuset_common_seq_show,
    2561                 :            :                 .private = FILE_EFFECTIVE_MEMLIST,
    2562                 :            :         },
    2563                 :            : 
    2564                 :            :         {
    2565                 :            :                 .name = "cpu_exclusive",
    2566                 :            :                 .read_u64 = cpuset_read_u64,
    2567                 :            :                 .write_u64 = cpuset_write_u64,
    2568                 :            :                 .private = FILE_CPU_EXCLUSIVE,
    2569                 :            :         },
    2570                 :            : 
    2571                 :            :         {
    2572                 :            :                 .name = "mem_exclusive",
    2573                 :            :                 .read_u64 = cpuset_read_u64,
    2574                 :            :                 .write_u64 = cpuset_write_u64,
    2575                 :            :                 .private = FILE_MEM_EXCLUSIVE,
    2576                 :            :         },
    2577                 :            : 
    2578                 :            :         {
    2579                 :            :                 .name = "mem_hardwall",
    2580                 :            :                 .read_u64 = cpuset_read_u64,
    2581                 :            :                 .write_u64 = cpuset_write_u64,
    2582                 :            :                 .private = FILE_MEM_HARDWALL,
    2583                 :            :         },
    2584                 :            : 
    2585                 :            :         {
    2586                 :            :                 .name = "sched_load_balance",
    2587                 :            :                 .read_u64 = cpuset_read_u64,
    2588                 :            :                 .write_u64 = cpuset_write_u64,
    2589                 :            :                 .private = FILE_SCHED_LOAD_BALANCE,
    2590                 :            :         },
    2591                 :            : 
    2592                 :            :         {
    2593                 :            :                 .name = "sched_relax_domain_level",
    2594                 :            :                 .read_s64 = cpuset_read_s64,
    2595                 :            :                 .write_s64 = cpuset_write_s64,
    2596                 :            :                 .private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
    2597                 :            :         },
    2598                 :            : 
    2599                 :            :         {
    2600                 :            :                 .name = "memory_migrate",
    2601                 :            :                 .read_u64 = cpuset_read_u64,
    2602                 :            :                 .write_u64 = cpuset_write_u64,
    2603                 :            :                 .private = FILE_MEMORY_MIGRATE,
    2604                 :            :         },
    2605                 :            : 
    2606                 :            :         {
    2607                 :            :                 .name = "memory_pressure",
    2608                 :            :                 .read_u64 = cpuset_read_u64,
    2609                 :            :                 .private = FILE_MEMORY_PRESSURE,
    2610                 :            :         },
    2611                 :            : 
    2612                 :            :         {
    2613                 :            :                 .name = "memory_spread_page",
    2614                 :            :                 .read_u64 = cpuset_read_u64,
    2615                 :            :                 .write_u64 = cpuset_write_u64,
    2616                 :            :                 .private = FILE_SPREAD_PAGE,
    2617                 :            :         },
    2618                 :            : 
    2619                 :            :         {
    2620                 :            :                 .name = "memory_spread_slab",
    2621                 :            :                 .read_u64 = cpuset_read_u64,
    2622                 :            :                 .write_u64 = cpuset_write_u64,
    2623                 :            :                 .private = FILE_SPREAD_SLAB,
    2624                 :            :         },
    2625                 :            : 
    2626                 :            :         {
    2627                 :            :                 .name = "memory_pressure_enabled",
    2628                 :            :                 .flags = CFTYPE_ONLY_ON_ROOT,
    2629                 :            :                 .read_u64 = cpuset_read_u64,
    2630                 :            :                 .write_u64 = cpuset_write_u64,
    2631                 :            :                 .private = FILE_MEMORY_PRESSURE_ENABLED,
    2632                 :            :         },
    2633                 :            : 
    2634                 :            :         { }     /* terminate */
    2635                 :            : };
    2636                 :            : 
    2637                 :            : /*
    2638                 :            :  * This is currently a minimal set for the default hierarchy. It can be
    2639                 :            :  * expanded later on by migrating more features and control files from v1.
    2640                 :            :  */
    2641                 :            : static struct cftype dfl_files[] = {
    2642                 :            :         {
    2643                 :            :                 .name = "cpus",
    2644                 :            :                 .seq_show = cpuset_common_seq_show,
    2645                 :            :                 .write = cpuset_write_resmask,
    2646                 :            :                 .max_write_len = (100U + 6 * NR_CPUS),
    2647                 :            :                 .private = FILE_CPULIST,
    2648                 :            :                 .flags = CFTYPE_NOT_ON_ROOT,
    2649                 :            :         },
    2650                 :            : 
    2651                 :            :         {
    2652                 :            :                 .name = "mems",
    2653                 :            :                 .seq_show = cpuset_common_seq_show,
    2654                 :            :                 .write = cpuset_write_resmask,
    2655                 :            :                 .max_write_len = (100U + 6 * MAX_NUMNODES),
    2656                 :            :                 .private = FILE_MEMLIST,
    2657                 :            :                 .flags = CFTYPE_NOT_ON_ROOT,
    2658                 :            :         },
    2659                 :            : 
    2660                 :            :         {
    2661                 :            :                 .name = "cpus.effective",
    2662                 :            :                 .seq_show = cpuset_common_seq_show,
    2663                 :            :                 .private = FILE_EFFECTIVE_CPULIST,
    2664                 :            :         },
    2665                 :            : 
    2666                 :            :         {
    2667                 :            :                 .name = "mems.effective",
    2668                 :            :                 .seq_show = cpuset_common_seq_show,
    2669                 :            :                 .private = FILE_EFFECTIVE_MEMLIST,
    2670                 :            :         },
    2671                 :            : 
    2672                 :            :         {
    2673                 :            :                 .name = "cpus.partition",
    2674                 :            :                 .seq_show = sched_partition_show,
    2675                 :            :                 .write = sched_partition_write,
    2676                 :            :                 .private = FILE_PARTITION_ROOT,
    2677                 :            :                 .flags = CFTYPE_NOT_ON_ROOT,
    2678                 :            :         },
    2679                 :            : 
    2680                 :            :         {
    2681                 :            :                 .name = "cpus.subpartitions",
    2682                 :            :                 .seq_show = cpuset_common_seq_show,
    2683                 :            :                 .private = FILE_SUBPARTS_CPULIST,
    2684                 :            :                 .flags = CFTYPE_DEBUG,
    2685                 :            :         },
    2686                 :            : 
    2687                 :            :         { }     /* terminate */
    2688                 :            : };
    2689                 :            : 
    2690                 :            : 
    2691                 :            : /*
    2692                 :            :  *      cpuset_css_alloc - allocate a cpuset css
    2693                 :            :  *      cgrp:   control group that the new cpuset will be part of
    2694                 :            :  */
    2695                 :            : 
    2696                 :            : static struct cgroup_subsys_state *
    2697                 :         30 : cpuset_css_alloc(struct cgroup_subsys_state *parent_css)
    2698                 :            : {
    2699                 :         30 :         struct cpuset *cs;
    2700                 :            : 
    2701         [ -  + ]:         30 :         if (!parent_css)
    2702                 :            :                 return &top_cpuset.css;
    2703                 :            : 
    2704                 :          0 :         cs = kzalloc(sizeof(*cs), GFP_KERNEL);
    2705         [ #  # ]:          0 :         if (!cs)
    2706                 :            :                 return ERR_PTR(-ENOMEM);
    2707                 :            : 
    2708         [ #  # ]:          0 :         if (alloc_cpumasks(cs, NULL)) {
    2709                 :          0 :                 kfree(cs);
    2710                 :          0 :                 return ERR_PTR(-ENOMEM);
    2711                 :            :         }
    2712                 :            : 
    2713                 :          0 :         set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
    2714                 :          0 :         nodes_clear(cs->mems_allowed);
    2715                 :          0 :         nodes_clear(cs->effective_mems);
    2716                 :          0 :         fmeter_init(&cs->fmeter);
    2717                 :          0 :         cs->relax_domain_level = -1;
    2718                 :            : 
    2719                 :          0 :         return &cs->css;
    2720                 :            : }
    2721                 :            : 
    2722                 :         30 : static int cpuset_css_online(struct cgroup_subsys_state *css)
    2723                 :            : {
    2724         [ -  + ]:         30 :         struct cpuset *cs = css_cs(css);
    2725         [ -  + ]:         30 :         struct cpuset *parent = parent_cs(cs);
    2726                 :          0 :         struct cpuset *tmp_cs;
    2727                 :          0 :         struct cgroup_subsys_state *pos_css;
    2728                 :            : 
    2729                 :          0 :         if (!parent)
    2730                 :            :                 return 0;
    2731                 :            : 
    2732                 :          0 :         get_online_cpus();
    2733                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2734                 :            : 
    2735                 :          0 :         set_bit(CS_ONLINE, &cs->flags);
    2736         [ #  # ]:          0 :         if (is_spread_page(parent))
    2737                 :          0 :                 set_bit(CS_SPREAD_PAGE, &cs->flags);
    2738         [ #  # ]:          0 :         if (is_spread_slab(parent))
    2739                 :          0 :                 set_bit(CS_SPREAD_SLAB, &cs->flags);
    2740                 :            : 
    2741                 :          0 :         cpuset_inc();
    2742                 :            : 
    2743                 :          0 :         spin_lock_irq(&callback_lock);
    2744   [ #  #  #  # ]:          0 :         if (is_in_v2_mode()) {
    2745                 :          0 :                 cpumask_copy(cs->effective_cpus, parent->effective_cpus);
    2746                 :          0 :                 cs->effective_mems = parent->effective_mems;
    2747                 :          0 :                 cs->use_parent_ecpus = true;
    2748                 :          0 :                 parent->child_ecpus_count++;
    2749                 :            :         }
    2750                 :          0 :         spin_unlock_irq(&callback_lock);
    2751                 :            : 
    2752         [ #  # ]:          0 :         if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
    2753                 :          0 :                 goto out_unlock;
    2754                 :            : 
    2755                 :            :         /*
    2756                 :            :          * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
    2757                 :            :          * set.  This flag handling is implemented in cgroup core for
    2758                 :            :          * histrical reasons - the flag may be specified during mount.
    2759                 :            :          *
    2760                 :            :          * Currently, if any sibling cpusets have exclusive cpus or mem, we
    2761                 :            :          * refuse to clone the configuration - thereby refusing the task to
    2762                 :            :          * be entered, and as a result refusing the sys_unshare() or
    2763                 :            :          * clone() which initiated it.  If this becomes a problem for some
    2764                 :            :          * users who wish to allow that scenario, then this could be
    2765                 :            :          * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
    2766                 :            :          * (and likewise for mems) to the new cgroup.
    2767                 :            :          */
    2768                 :          0 :         rcu_read_lock();
    2769   [ #  #  #  # ]:          0 :         cpuset_for_each_child(tmp_cs, pos_css, parent) {
    2770   [ #  #  #  # ]:          0 :                 if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) {
    2771                 :          0 :                         rcu_read_unlock();
    2772                 :          0 :                         goto out_unlock;
    2773                 :            :                 }
    2774                 :            :         }
    2775                 :          0 :         rcu_read_unlock();
    2776                 :            : 
    2777                 :          0 :         spin_lock_irq(&callback_lock);
    2778                 :          0 :         cs->mems_allowed = parent->mems_allowed;
    2779                 :          0 :         cs->effective_mems = parent->mems_allowed;
    2780                 :          0 :         cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
    2781                 :          0 :         cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
    2782                 :          0 :         spin_unlock_irq(&callback_lock);
    2783                 :          0 : out_unlock:
    2784                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2785                 :          0 :         put_online_cpus();
    2786                 :          0 :         return 0;
    2787                 :            : }
    2788                 :            : 
    2789                 :            : /*
    2790                 :            :  * If the cpuset being removed has its flag 'sched_load_balance'
    2791                 :            :  * enabled, then simulate turning sched_load_balance off, which
    2792                 :            :  * will call rebuild_sched_domains_locked(). That is not needed
    2793                 :            :  * in the default hierarchy where only changes in partition
    2794                 :            :  * will cause repartitioning.
    2795                 :            :  *
    2796                 :            :  * If the cpuset has the 'sched.partition' flag enabled, simulate
    2797                 :            :  * turning 'sched.partition" off.
    2798                 :            :  */
    2799                 :            : 
    2800                 :          0 : static void cpuset_css_offline(struct cgroup_subsys_state *css)
    2801                 :            : {
    2802         [ #  # ]:          0 :         struct cpuset *cs = css_cs(css);
    2803                 :            : 
    2804                 :          0 :         get_online_cpus();
    2805                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2806                 :            : 
    2807         [ #  # ]:          0 :         if (is_partition_root(cs))
    2808                 :          0 :                 update_prstate(cs, 0);
    2809                 :            : 
    2810   [ #  #  #  #  :          0 :         if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
                   #  # ]
    2811                 :            :             is_sched_load_balance(cs))
    2812                 :          0 :                 update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
    2813                 :            : 
    2814         [ #  # ]:          0 :         if (cs->use_parent_ecpus) {
    2815         [ #  # ]:          0 :                 struct cpuset *parent = parent_cs(cs);
    2816                 :            : 
    2817                 :          0 :                 cs->use_parent_ecpus = false;
    2818                 :          0 :                 parent->child_ecpus_count--;
    2819                 :            :         }
    2820                 :            : 
    2821                 :          0 :         cpuset_dec();
    2822                 :          0 :         clear_bit(CS_ONLINE, &cs->flags);
    2823                 :            : 
    2824                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2825                 :          0 :         put_online_cpus();
    2826                 :          0 : }
    2827                 :            : 
    2828                 :          0 : static void cpuset_css_free(struct cgroup_subsys_state *css)
    2829                 :            : {
    2830         [ #  # ]:          0 :         struct cpuset *cs = css_cs(css);
    2831                 :            : 
    2832                 :          0 :         free_cpuset(cs);
    2833                 :          0 : }
    2834                 :            : 
    2835                 :         60 : static void cpuset_bind(struct cgroup_subsys_state *root_css)
    2836                 :            : {
    2837                 :         60 :         percpu_down_write(&cpuset_rwsem);
    2838                 :         60 :         spin_lock_irq(&callback_lock);
    2839                 :            : 
    2840   [ +  +  +  + ]:        120 :         if (is_in_v2_mode()) {
    2841                 :         30 :                 cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
    2842                 :         30 :                 top_cpuset.mems_allowed = node_possible_map;
    2843                 :            :         } else {
    2844                 :         30 :                 cpumask_copy(top_cpuset.cpus_allowed,
    2845                 :            :                              top_cpuset.effective_cpus);
    2846                 :         30 :                 top_cpuset.mems_allowed = top_cpuset.effective_mems;
    2847                 :            :         }
    2848                 :            : 
    2849                 :         60 :         spin_unlock_irq(&callback_lock);
    2850                 :         60 :         percpu_up_write(&cpuset_rwsem);
    2851                 :         60 : }
    2852                 :            : 
    2853                 :            : /*
    2854                 :            :  * Make sure the new task conform to the current state of its parent,
    2855                 :            :  * which could have been changed by cpuset just after it inherits the
    2856                 :            :  * state from the parent and before it sits on the cgroup's task list.
    2857                 :            :  */
    2858                 :      22953 : static void cpuset_fork(struct task_struct *task)
    2859                 :            : {
    2860         [ -  + ]:      22953 :         if (task_css_is_root(task, cpuset_cgrp_id))
    2861                 :            :                 return;
    2862                 :            : 
    2863                 :          0 :         set_cpus_allowed_ptr(task, current->cpus_ptr);
    2864                 :          0 :         task->mems_allowed = current->mems_allowed;
    2865                 :            : }
    2866                 :            : 
    2867                 :            : struct cgroup_subsys cpuset_cgrp_subsys = {
    2868                 :            :         .css_alloc      = cpuset_css_alloc,
    2869                 :            :         .css_online     = cpuset_css_online,
    2870                 :            :         .css_offline    = cpuset_css_offline,
    2871                 :            :         .css_free       = cpuset_css_free,
    2872                 :            :         .can_attach     = cpuset_can_attach,
    2873                 :            :         .cancel_attach  = cpuset_cancel_attach,
    2874                 :            :         .attach         = cpuset_attach,
    2875                 :            :         .post_attach    = cpuset_post_attach,
    2876                 :            :         .bind           = cpuset_bind,
    2877                 :            :         .fork           = cpuset_fork,
    2878                 :            :         .legacy_cftypes = legacy_files,
    2879                 :            :         .dfl_cftypes    = dfl_files,
    2880                 :            :         .early_init     = true,
    2881                 :            :         .threaded       = true,
    2882                 :            : };
    2883                 :            : 
    2884                 :            : /**
    2885                 :            :  * cpuset_init - initialize cpusets at system boot
    2886                 :            :  *
    2887                 :            :  * Description: Initialize top_cpuset
    2888                 :            :  **/
    2889                 :            : 
    2890                 :         30 : int __init cpuset_init(void)
    2891                 :            : {
    2892         [ -  + ]:         30 :         BUG_ON(percpu_init_rwsem(&cpuset_rwsem));
    2893                 :            : 
    2894                 :         30 :         BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL));
    2895                 :         30 :         BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL));
    2896                 :         30 :         BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL));
    2897                 :            : 
    2898                 :         30 :         cpumask_setall(top_cpuset.cpus_allowed);
    2899                 :         30 :         nodes_setall(top_cpuset.mems_allowed);
    2900                 :         30 :         cpumask_setall(top_cpuset.effective_cpus);
    2901                 :         30 :         nodes_setall(top_cpuset.effective_mems);
    2902                 :            : 
    2903                 :         30 :         fmeter_init(&top_cpuset.fmeter);
    2904                 :         30 :         set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
    2905                 :         30 :         top_cpuset.relax_domain_level = -1;
    2906                 :            : 
    2907                 :         30 :         BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL));
    2908                 :            : 
    2909                 :         30 :         return 0;
    2910                 :            : }
    2911                 :            : 
    2912                 :            : /*
    2913                 :            :  * If CPU and/or memory hotplug handlers, below, unplug any CPUs
    2914                 :            :  * or memory nodes, we need to walk over the cpuset hierarchy,
    2915                 :            :  * removing that CPU or node from all cpusets.  If this removes the
    2916                 :            :  * last CPU or node from a cpuset, then move the tasks in the empty
    2917                 :            :  * cpuset to its next-highest non-empty parent.
    2918                 :            :  */
    2919                 :          0 : static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
    2920                 :            : {
    2921                 :          0 :         struct cpuset *parent;
    2922                 :            : 
    2923                 :            :         /*
    2924                 :            :          * Find its next-highest non-empty parent, (top cpuset
    2925                 :            :          * has online cpus, so can't be empty).
    2926                 :            :          */
    2927         [ #  # ]:          0 :         parent = parent_cs(cs);
    2928   [ #  #  #  # ]:          0 :         while (cpumask_empty(parent->cpus_allowed) ||
    2929                 :            :                         nodes_empty(parent->mems_allowed))
    2930         [ #  # ]:          0 :                 parent = parent_cs(parent);
    2931                 :            : 
    2932         [ #  # ]:          0 :         if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {
    2933                 :          0 :                 pr_err("cpuset: failed to transfer tasks out of empty cpuset ");
    2934                 :          0 :                 pr_cont_cgroup_name(cs->css.cgroup);
    2935                 :          0 :                 pr_cont("\n");
    2936                 :            :         }
    2937                 :          0 : }
    2938                 :            : 
    2939                 :            : static void
    2940                 :          0 : hotplug_update_tasks_legacy(struct cpuset *cs,
    2941                 :            :                             struct cpumask *new_cpus, nodemask_t *new_mems,
    2942                 :            :                             bool cpus_updated, bool mems_updated)
    2943                 :            : {
    2944                 :          0 :         bool is_empty;
    2945                 :            : 
    2946                 :          0 :         spin_lock_irq(&callback_lock);
    2947                 :          0 :         cpumask_copy(cs->cpus_allowed, new_cpus);
    2948                 :          0 :         cpumask_copy(cs->effective_cpus, new_cpus);
    2949                 :          0 :         cs->mems_allowed = *new_mems;
    2950                 :          0 :         cs->effective_mems = *new_mems;
    2951                 :          0 :         spin_unlock_irq(&callback_lock);
    2952                 :            : 
    2953                 :            :         /*
    2954                 :            :          * Don't call update_tasks_cpumask() if the cpuset becomes empty,
    2955                 :            :          * as the tasks will be migratecd to an ancestor.
    2956                 :            :          */
    2957   [ #  #  #  # ]:          0 :         if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
    2958                 :          0 :                 update_tasks_cpumask(cs);
    2959   [ #  #  #  # ]:          0 :         if (mems_updated && !nodes_empty(cs->mems_allowed))
    2960                 :          0 :                 update_tasks_nodemask(cs);
    2961                 :            : 
    2962   [ #  #  #  # ]:          0 :         is_empty = cpumask_empty(cs->cpus_allowed) ||
    2963                 :            :                    nodes_empty(cs->mems_allowed);
    2964                 :            : 
    2965                 :          0 :         percpu_up_write(&cpuset_rwsem);
    2966                 :            : 
    2967                 :            :         /*
    2968                 :            :          * Move tasks to the nearest ancestor with execution resources,
    2969                 :            :          * This is full cgroup operation which will also call back into
    2970                 :            :          * cpuset. Should be done outside any lock.
    2971                 :            :          */
    2972         [ #  # ]:          0 :         if (is_empty)
    2973                 :          0 :                 remove_tasks_in_empty_cpuset(cs);
    2974                 :            : 
    2975                 :          0 :         percpu_down_write(&cpuset_rwsem);
    2976                 :          0 : }
    2977                 :            : 
    2978                 :            : static void
    2979                 :          0 : hotplug_update_tasks(struct cpuset *cs,
    2980                 :            :                      struct cpumask *new_cpus, nodemask_t *new_mems,
    2981                 :            :                      bool cpus_updated, bool mems_updated)
    2982                 :            : {
    2983         [ #  # ]:          0 :         if (cpumask_empty(new_cpus))
    2984         [ #  # ]:          0 :                 cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
    2985         [ #  # ]:          0 :         if (nodes_empty(*new_mems))
    2986         [ #  # ]:          0 :                 *new_mems = parent_cs(cs)->effective_mems;
    2987                 :            : 
    2988                 :          0 :         spin_lock_irq(&callback_lock);
    2989                 :          0 :         cpumask_copy(cs->effective_cpus, new_cpus);
    2990                 :          0 :         cs->effective_mems = *new_mems;
    2991                 :          0 :         spin_unlock_irq(&callback_lock);
    2992                 :            : 
    2993         [ #  # ]:          0 :         if (cpus_updated)
    2994                 :          0 :                 update_tasks_cpumask(cs);
    2995         [ #  # ]:          0 :         if (mems_updated)
    2996                 :          0 :                 update_tasks_nodemask(cs);
    2997                 :          0 : }
    2998                 :            : 
    2999                 :            : static bool force_rebuild;
    3000                 :            : 
    3001                 :          0 : void cpuset_force_rebuild(void)
    3002                 :            : {
    3003                 :          0 :         force_rebuild = true;
    3004                 :          0 : }
    3005                 :            : 
    3006                 :            : /**
    3007                 :            :  * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
    3008                 :            :  * @cs: cpuset in interest
    3009                 :            :  * @tmp: the tmpmasks structure pointer
    3010                 :            :  *
    3011                 :            :  * Compare @cs's cpu and mem masks against top_cpuset and if some have gone
    3012                 :            :  * offline, update @cs accordingly.  If @cs ends up with no CPU or memory,
    3013                 :            :  * all its tasks are moved to the nearest ancestor with both resources.
    3014                 :            :  */
    3015                 :          0 : static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
    3016                 :            : {
    3017                 :          0 :         static cpumask_t new_cpus;
    3018                 :          0 :         static nodemask_t new_mems;
    3019                 :          0 :         bool cpus_updated;
    3020                 :          0 :         bool mems_updated;
    3021                 :          0 :         struct cpuset *parent;
    3022                 :          0 : retry:
    3023   [ #  #  #  # ]:          0 :         wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
    3024                 :            : 
    3025                 :          0 :         percpu_down_write(&cpuset_rwsem);
    3026                 :            : 
    3027                 :            :         /*
    3028                 :            :          * We have raced with task attaching. We wait until attaching
    3029                 :            :          * is finished, so we won't attach a task to an empty cpuset.
    3030                 :            :          */
    3031         [ #  # ]:          0 :         if (cs->attach_in_progress) {
    3032                 :          0 :                 percpu_up_write(&cpuset_rwsem);
    3033                 :          0 :                 goto retry;
    3034                 :            :         }
    3035                 :            : 
    3036         [ #  # ]:          0 :         parent =  parent_cs(cs);
    3037         [ #  # ]:          0 :         compute_effective_cpumask(&new_cpus, cs, parent);
    3038                 :          0 :         nodes_and(new_mems, cs->mems_allowed, parent->effective_mems);
    3039                 :            : 
    3040         [ #  # ]:          0 :         if (cs->nr_subparts_cpus)
    3041                 :            :                 /*
    3042                 :            :                  * Make sure that CPUs allocated to child partitions
    3043                 :            :                  * do not show up in effective_cpus.
    3044                 :            :                  */
    3045                 :          0 :                 cpumask_andnot(&new_cpus, &new_cpus, cs->subparts_cpus);
    3046                 :            : 
    3047   [ #  #  #  # ]:          0 :         if (!tmp || !cs->partition_root_state)
    3048                 :          0 :                 goto update_tasks;
    3049                 :            : 
    3050                 :            :         /*
    3051                 :            :          * In the unlikely event that a partition root has empty
    3052                 :            :          * effective_cpus or its parent becomes erroneous, we have to
    3053                 :            :          * transition it to the erroneous state.
    3054                 :            :          */
    3055   [ #  #  #  # ]:          0 :         if (is_partition_root(cs) && (cpumask_empty(&new_cpus) ||
    3056         [ #  # ]:          0 :            (parent->partition_root_state == PRS_ERROR))) {
    3057         [ #  # ]:          0 :                 if (cs->nr_subparts_cpus) {
    3058                 :          0 :                         cs->nr_subparts_cpus = 0;
    3059         [ #  # ]:          0 :                         cpumask_clear(cs->subparts_cpus);
    3060         [ #  # ]:          0 :                         compute_effective_cpumask(&new_cpus, cs, parent);
    3061                 :            :                 }
    3062                 :            : 
    3063                 :            :                 /*
    3064                 :            :                  * If the effective_cpus is empty because the child
    3065                 :            :                  * partitions take away all the CPUs, we can keep
    3066                 :            :                  * the current partition and let the child partitions
    3067                 :            :                  * fight for available CPUs.
    3068                 :            :                  */
    3069   [ #  #  #  # ]:          0 :                 if ((parent->partition_root_state == PRS_ERROR) ||
    3070                 :            :                      cpumask_empty(&new_cpus)) {
    3071                 :          0 :                         update_parent_subparts_cpumask(cs, partcmd_disable,
    3072                 :            :                                                        NULL, tmp);
    3073                 :          0 :                         cs->partition_root_state = PRS_ERROR;
    3074                 :            :                 }
    3075                 :          0 :                 cpuset_force_rebuild();
    3076                 :            :         }
    3077                 :            : 
    3078                 :            :         /*
    3079                 :            :          * On the other hand, an erroneous partition root may be transitioned
    3080                 :            :          * back to a regular one or a partition root with no CPU allocated
    3081                 :            :          * from the parent may change to erroneous.
    3082                 :            :          */
    3083         [ #  # ]:          0 :         if (is_partition_root(parent) &&
    3084   [ #  #  #  # ]:          0 :            ((cs->partition_root_state == PRS_ERROR) ||
    3085         [ #  # ]:          0 :             !cpumask_intersects(&new_cpus, parent->subparts_cpus)) &&
    3086                 :          0 :              update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp))
    3087                 :          0 :                 cpuset_force_rebuild();
    3088                 :            : 
    3089                 :          0 : update_tasks:
    3090                 :          0 :         cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
    3091                 :          0 :         mems_updated = !nodes_equal(new_mems, cs->effective_mems);
    3092                 :            : 
    3093   [ #  #  #  # ]:          0 :         if (is_in_v2_mode())
    3094                 :          0 :                 hotplug_update_tasks(cs, &new_cpus, &new_mems,
    3095                 :            :                                      cpus_updated, mems_updated);
    3096                 :            :         else
    3097                 :          0 :                 hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems,
    3098                 :            :                                             cpus_updated, mems_updated);
    3099                 :            : 
    3100                 :          0 :         percpu_up_write(&cpuset_rwsem);
    3101                 :          0 : }
    3102                 :            : 
    3103                 :            : /**
    3104                 :            :  * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset
    3105                 :            :  *
    3106                 :            :  * This function is called after either CPU or memory configuration has
    3107                 :            :  * changed and updates cpuset accordingly.  The top_cpuset is always
    3108                 :            :  * synchronized to cpu_active_mask and N_MEMORY, which is necessary in
    3109                 :            :  * order to make cpusets transparent (of no affect) on systems that are
    3110                 :            :  * actively using CPU hotplug but making no active use of cpusets.
    3111                 :            :  *
    3112                 :            :  * Non-root cpusets are only affected by offlining.  If any CPUs or memory
    3113                 :            :  * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on
    3114                 :            :  * all descendants.
    3115                 :            :  *
    3116                 :            :  * Note that CPU offlining during suspend is ignored.  We don't modify
    3117                 :            :  * cpusets across suspend/resume cycles at all.
    3118                 :            :  */
    3119                 :          0 : static void cpuset_hotplug_workfn(struct work_struct *work)
    3120                 :            : {
    3121                 :          0 :         static cpumask_t new_cpus;
    3122                 :          0 :         static nodemask_t new_mems;
    3123                 :          0 :         bool cpus_updated, mems_updated;
    3124         [ #  # ]:          0 :         bool on_dfl = is_in_v2_mode();
    3125                 :          0 :         struct tmpmasks tmp, *ptmp = NULL;
    3126                 :            : 
    3127   [ #  #  #  # ]:          0 :         if (on_dfl && !alloc_cpumasks(NULL, &tmp))
    3128                 :          0 :                 ptmp = &tmp;
    3129                 :            : 
    3130                 :          0 :         percpu_down_write(&cpuset_rwsem);
    3131                 :            : 
    3132                 :            :         /* fetch the available cpus/mems and find out which changed how */
    3133                 :          0 :         cpumask_copy(&new_cpus, cpu_active_mask);
    3134                 :          0 :         new_mems = node_states[N_MEMORY];
    3135                 :            : 
    3136                 :            :         /*
    3137                 :            :          * If subparts_cpus is populated, it is likely that the check below
    3138                 :            :          * will produce a false positive on cpus_updated when the cpu list
    3139                 :            :          * isn't changed. It is extra work, but it is better to be safe.
    3140                 :            :          */
    3141                 :          0 :         cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
    3142                 :          0 :         mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
    3143                 :            : 
    3144                 :            :         /* synchronize cpus_allowed to cpu_active_mask */
    3145         [ #  # ]:          0 :         if (cpus_updated) {
    3146                 :          0 :                 spin_lock_irq(&callback_lock);
    3147         [ #  # ]:          0 :                 if (!on_dfl)
    3148                 :          0 :                         cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
    3149                 :            :                 /*
    3150                 :            :                  * Make sure that CPUs allocated to child partitions
    3151                 :            :                  * do not show up in effective_cpus. If no CPU is left,
    3152                 :            :                  * we clear the subparts_cpus & let the child partitions
    3153                 :            :                  * fight for the CPUs again.
    3154                 :            :                  */
    3155         [ #  # ]:          0 :                 if (top_cpuset.nr_subparts_cpus) {
    3156         [ #  # ]:          0 :                         if (cpumask_subset(&new_cpus,
    3157                 :            :                                            top_cpuset.subparts_cpus)) {
    3158                 :          0 :                                 top_cpuset.nr_subparts_cpus = 0;
    3159                 :          0 :                                 cpumask_clear(top_cpuset.subparts_cpus);
    3160                 :            :                         } else {
    3161                 :          0 :                                 cpumask_andnot(&new_cpus, &new_cpus,
    3162                 :            :                                                top_cpuset.subparts_cpus);
    3163                 :            :                         }
    3164                 :            :                 }
    3165                 :          0 :                 cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
    3166                 :          0 :                 spin_unlock_irq(&callback_lock);
    3167                 :            :                 /* we don't mess with cpumasks of tasks in top_cpuset */
    3168                 :            :         }
    3169                 :            : 
    3170                 :            :         /* synchronize mems_allowed to N_MEMORY */
    3171         [ #  # ]:          0 :         if (mems_updated) {
    3172                 :          0 :                 spin_lock_irq(&callback_lock);
    3173         [ #  # ]:          0 :                 if (!on_dfl)
    3174                 :          0 :                         top_cpuset.mems_allowed = new_mems;
    3175                 :          0 :                 top_cpuset.effective_mems = new_mems;
    3176                 :          0 :                 spin_unlock_irq(&callback_lock);
    3177                 :          0 :                 update_tasks_nodemask(&top_cpuset);
    3178                 :            :         }
    3179                 :            : 
    3180                 :          0 :         percpu_up_write(&cpuset_rwsem);
    3181                 :            : 
    3182                 :            :         /* if cpus or mems changed, we need to propagate to descendants */
    3183         [ #  # ]:          0 :         if (cpus_updated || mems_updated) {
    3184                 :          0 :                 struct cpuset *cs;
    3185                 :          0 :                 struct cgroup_subsys_state *pos_css;
    3186                 :            : 
    3187                 :          0 :                 rcu_read_lock();
    3188   [ #  #  #  # ]:          0 :                 cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
    3189   [ #  #  #  # ]:          0 :                         if (cs == &top_cpuset || !css_tryget_online(&cs->css))
    3190                 :          0 :                                 continue;
    3191                 :          0 :                         rcu_read_unlock();
    3192                 :            : 
    3193                 :          0 :                         cpuset_hotplug_update_tasks(cs, ptmp);
    3194                 :            : 
    3195                 :          0 :                         rcu_read_lock();
    3196         [ #  # ]:          0 :                         css_put(&cs->css);
    3197                 :            :                 }
    3198                 :          0 :                 rcu_read_unlock();
    3199                 :            :         }
    3200                 :            : 
    3201                 :            :         /* rebuild sched domains if cpus_allowed has changed */
    3202   [ #  #  #  # ]:          0 :         if (cpus_updated || force_rebuild) {
    3203                 :          0 :                 force_rebuild = false;
    3204                 :          0 :                 rebuild_sched_domains();
    3205                 :            :         }
    3206                 :            : 
    3207                 :          0 :         free_cpumasks(NULL, ptmp);
    3208                 :          0 : }
    3209                 :            : 
    3210                 :          0 : void cpuset_update_active_cpus(void)
    3211                 :            : {
    3212                 :            :         /*
    3213                 :            :          * We're inside cpu hotplug critical region which usually nests
    3214                 :            :          * inside cgroup synchronization.  Bounce actual hotplug processing
    3215                 :            :          * to a work item to avoid reverse locking order.
    3216                 :            :          */
    3217                 :          0 :         schedule_work(&cpuset_hotplug_work);
    3218                 :          0 : }
    3219                 :            : 
    3220                 :          0 : void cpuset_wait_for_hotplug(void)
    3221                 :            : {
    3222                 :          0 :         flush_work(&cpuset_hotplug_work);
    3223                 :          0 : }
    3224                 :            : 
    3225                 :            : /*
    3226                 :            :  * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY].
    3227                 :            :  * Call this routine anytime after node_states[N_MEMORY] changes.
    3228                 :            :  * See cpuset_update_active_cpus() for CPU hotplug handling.
    3229                 :            :  */
    3230                 :            : static int cpuset_track_online_nodes(struct notifier_block *self,
    3231                 :            :                                 unsigned long action, void *arg)
    3232                 :            : {
    3233                 :            :         schedule_work(&cpuset_hotplug_work);
    3234                 :            :         return NOTIFY_OK;
    3235                 :            : }
    3236                 :            : 
    3237                 :            : static struct notifier_block cpuset_track_online_nodes_nb = {
    3238                 :            :         .notifier_call = cpuset_track_online_nodes,
    3239                 :            :         .priority = 10,         /* ??! */
    3240                 :            : };
    3241                 :            : 
    3242                 :            : /**
    3243                 :            :  * cpuset_init_smp - initialize cpus_allowed
    3244                 :            :  *
    3245                 :            :  * Description: Finish top cpuset after cpu, node maps are initialized
    3246                 :            :  */
    3247                 :         30 : void __init cpuset_init_smp(void)
    3248                 :            : {
    3249                 :         30 :         cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
    3250                 :         30 :         top_cpuset.mems_allowed = node_states[N_MEMORY];
    3251                 :         30 :         top_cpuset.old_mems_allowed = top_cpuset.mems_allowed;
    3252                 :            : 
    3253                 :         30 :         cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);
    3254                 :         30 :         top_cpuset.effective_mems = node_states[N_MEMORY];
    3255                 :            : 
    3256                 :         30 :         register_hotmemory_notifier(&cpuset_track_online_nodes_nb);
    3257                 :            : 
    3258                 :         30 :         cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0);
    3259         [ -  + ]:         30 :         BUG_ON(!cpuset_migrate_mm_wq);
    3260                 :         30 : }
    3261                 :            : 
    3262                 :            : /**
    3263                 :            :  * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
    3264                 :            :  * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
    3265                 :            :  * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
    3266                 :            :  *
    3267                 :            :  * Description: Returns the cpumask_var_t cpus_allowed of the cpuset
    3268                 :            :  * attached to the specified @tsk.  Guaranteed to return some non-empty
    3269                 :            :  * subset of cpu_online_mask, even if this means going outside the
    3270                 :            :  * tasks cpuset.
    3271                 :            :  **/
    3272                 :            : 
    3273                 :          0 : void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
    3274                 :            : {
    3275                 :          0 :         unsigned long flags;
    3276                 :            : 
    3277                 :          0 :         spin_lock_irqsave(&callback_lock, flags);
    3278                 :          0 :         rcu_read_lock();
    3279         [ #  # ]:          0 :         guarantee_online_cpus(task_cs(tsk), pmask);
    3280                 :          0 :         rcu_read_unlock();
    3281                 :          0 :         spin_unlock_irqrestore(&callback_lock, flags);
    3282                 :          0 : }
    3283                 :            : 
    3284                 :            : /**
    3285                 :            :  * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe.
    3286                 :            :  * @tsk: pointer to task_struct with which the scheduler is struggling
    3287                 :            :  *
    3288                 :            :  * Description: In the case that the scheduler cannot find an allowed cpu in
    3289                 :            :  * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy
    3290                 :            :  * mode however, this value is the same as task_cs(tsk)->effective_cpus,
    3291                 :            :  * which will not contain a sane cpumask during cases such as cpu hotplugging.
    3292                 :            :  * This is the absolute last resort for the scheduler and it is only used if
    3293                 :            :  * _every_ other avenue has been traveled.
    3294                 :            :  **/
    3295                 :            : 
    3296                 :          0 : void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
    3297                 :            : {
    3298                 :          0 :         rcu_read_lock();
    3299   [ #  #  #  # ]:          0 :         do_set_cpus_allowed(tsk, is_in_v2_mode() ?
    3300                 :            :                 task_cs(tsk)->cpus_allowed : cpu_possible_mask);
    3301                 :          0 :         rcu_read_unlock();
    3302                 :            : 
    3303                 :            :         /*
    3304                 :            :          * We own tsk->cpus_allowed, nobody can change it under us.
    3305                 :            :          *
    3306                 :            :          * But we used cs && cs->cpus_allowed lockless and thus can
    3307                 :            :          * race with cgroup_attach_task() or update_cpumask() and get
    3308                 :            :          * the wrong tsk->cpus_allowed. However, both cases imply the
    3309                 :            :          * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr()
    3310                 :            :          * which takes task_rq_lock().
    3311                 :            :          *
    3312                 :            :          * If we are called after it dropped the lock we must see all
    3313                 :            :          * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary
    3314                 :            :          * set any mask even if it is not right from task_cs() pov,
    3315                 :            :          * the pending set_cpus_allowed_ptr() will fix things.
    3316                 :            :          *
    3317                 :            :          * select_fallback_rq() will fix things ups and set cpu_possible_mask
    3318                 :            :          * if required.
    3319                 :            :          */
    3320                 :          0 : }
    3321                 :            : 
    3322                 :         30 : void __init cpuset_init_current_mems_allowed(void)
    3323                 :            : {
    3324                 :         30 :         nodes_setall(current->mems_allowed);
    3325                 :         30 : }
    3326                 :            : 
    3327                 :            : /**
    3328                 :            :  * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
    3329                 :            :  * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
    3330                 :            :  *
    3331                 :            :  * Description: Returns the nodemask_t mems_allowed of the cpuset
    3332                 :            :  * attached to the specified @tsk.  Guaranteed to return some non-empty
    3333                 :            :  * subset of node_states[N_MEMORY], even if this means going outside the
    3334                 :            :  * tasks cpuset.
    3335                 :            :  **/
    3336                 :            : 
    3337                 :          0 : nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
    3338                 :            : {
    3339                 :          0 :         nodemask_t mask;
    3340                 :          0 :         unsigned long flags;
    3341                 :            : 
    3342                 :          0 :         spin_lock_irqsave(&callback_lock, flags);
    3343                 :          0 :         rcu_read_lock();
    3344         [ #  # ]:          0 :         guarantee_online_mems(task_cs(tsk), &mask);
    3345                 :          0 :         rcu_read_unlock();
    3346                 :          0 :         spin_unlock_irqrestore(&callback_lock, flags);
    3347                 :            : 
    3348                 :          0 :         return mask;
    3349                 :            : }
    3350                 :            : 
    3351                 :            : /**
    3352                 :            :  * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed
    3353                 :            :  * @nodemask: the nodemask to be checked
    3354                 :            :  *
    3355                 :            :  * Are any of the nodes in the nodemask allowed in current->mems_allowed?
    3356                 :            :  */
    3357                 :          0 : int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
    3358                 :            : {
    3359                 :          0 :         return nodes_intersects(*nodemask, current->mems_allowed);
    3360                 :            : }
    3361                 :            : 
    3362                 :            : /*
    3363                 :            :  * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
    3364                 :            :  * mem_hardwall ancestor to the specified cpuset.  Call holding
    3365                 :            :  * callback_lock.  If no ancestor is mem_exclusive or mem_hardwall
    3366                 :            :  * (an unusual configuration), then returns the root cpuset.
    3367                 :            :  */
    3368                 :          0 : static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
    3369                 :            : {
    3370   [ #  #  #  #  :          0 :         while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs))
                   #  # ]
    3371                 :            :                 cs = parent_cs(cs);
    3372                 :          0 :         return cs;
    3373                 :            : }
    3374                 :            : 
    3375                 :            : /**
    3376                 :            :  * cpuset_node_allowed - Can we allocate on a memory node?
    3377                 :            :  * @node: is this an allowed node?
    3378                 :            :  * @gfp_mask: memory allocation flags
    3379                 :            :  *
    3380                 :            :  * If we're in interrupt, yes, we can always allocate.  If @node is set in
    3381                 :            :  * current's mems_allowed, yes.  If it's not a __GFP_HARDWALL request and this
    3382                 :            :  * node is set in the nearest hardwalled cpuset ancestor to current's cpuset,
    3383                 :            :  * yes.  If current has access to memory reserves as an oom victim, yes.
    3384                 :            :  * Otherwise, no.
    3385                 :            :  *
    3386                 :            :  * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
    3387                 :            :  * and do not allow allocations outside the current tasks cpuset
    3388                 :            :  * unless the task has been OOM killed.
    3389                 :            :  * GFP_KERNEL allocations are not so marked, so can escape to the
    3390                 :            :  * nearest enclosing hardwalled ancestor cpuset.
    3391                 :            :  *
    3392                 :            :  * Scanning up parent cpusets requires callback_lock.  The
    3393                 :            :  * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
    3394                 :            :  * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
    3395                 :            :  * current tasks mems_allowed came up empty on the first pass over
    3396                 :            :  * the zonelist.  So only GFP_KERNEL allocations, if all nodes in the
    3397                 :            :  * cpuset are short of memory, might require taking the callback_lock.
    3398                 :            :  *
    3399                 :            :  * The first call here from mm/page_alloc:get_page_from_freelist()
    3400                 :            :  * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
    3401                 :            :  * so no allocation on a node outside the cpuset is allowed (unless
    3402                 :            :  * in interrupt, of course).
    3403                 :            :  *
    3404                 :            :  * The second pass through get_page_from_freelist() doesn't even call
    3405                 :            :  * here for GFP_ATOMIC calls.  For those calls, the __alloc_pages()
    3406                 :            :  * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
    3407                 :            :  * in alloc_flags.  That logic and the checks below have the combined
    3408                 :            :  * affect that:
    3409                 :            :  *      in_interrupt - any node ok (current task context irrelevant)
    3410                 :            :  *      GFP_ATOMIC   - any node ok
    3411                 :            :  *      tsk_is_oom_victim   - any node ok
    3412                 :            :  *      GFP_KERNEL   - any node in enclosing hardwalled cpuset ok
    3413                 :            :  *      GFP_USER     - only nodes in current tasks mems allowed ok.
    3414                 :            :  */
    3415                 :          0 : bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
    3416                 :            : {
    3417                 :          0 :         struct cpuset *cs;              /* current cpuset ancestors */
    3418                 :          0 :         int allowed;                    /* is allocation in zone z allowed? */
    3419                 :          0 :         unsigned long flags;
    3420                 :            : 
    3421         [ #  # ]:          0 :         if (in_interrupt())
    3422                 :            :                 return true;
    3423         [ #  # ]:          0 :         if (node_isset(node, current->mems_allowed))
    3424                 :            :                 return true;
    3425                 :            :         /*
    3426                 :            :          * Allow tasks that have access to memory reserves because they have
    3427                 :            :          * been OOM killed to get memory anywhere.
    3428                 :            :          */
    3429         [ #  # ]:          0 :         if (unlikely(tsk_is_oom_victim(current)))
    3430                 :            :                 return true;
    3431         [ #  # ]:          0 :         if (gfp_mask & __GFP_HARDWALL)      /* If hardwall request, stop here */
    3432                 :            :                 return false;
    3433                 :            : 
    3434         [ #  # ]:          0 :         if (current->flags & PF_EXITING) /* Let dying task have memory */
    3435                 :            :                 return true;
    3436                 :            : 
    3437                 :            :         /* Not hardwall and node outside mems_allowed: scan up cpusets */
    3438                 :          0 :         spin_lock_irqsave(&callback_lock, flags);
    3439                 :            : 
    3440                 :          0 :         rcu_read_lock();
    3441         [ #  # ]:          0 :         cs = nearest_hardwall_ancestor(task_cs(current));
    3442                 :          0 :         allowed = node_isset(node, cs->mems_allowed);
    3443                 :          0 :         rcu_read_unlock();
    3444                 :            : 
    3445                 :          0 :         spin_unlock_irqrestore(&callback_lock, flags);
    3446                 :          0 :         return allowed;
    3447                 :            : }
    3448                 :            : 
    3449                 :            : /**
    3450                 :            :  * cpuset_mem_spread_node() - On which node to begin search for a file page
    3451                 :            :  * cpuset_slab_spread_node() - On which node to begin search for a slab page
    3452                 :            :  *
    3453                 :            :  * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
    3454                 :            :  * tasks in a cpuset with is_spread_page or is_spread_slab set),
    3455                 :            :  * and if the memory allocation used cpuset_mem_spread_node()
    3456                 :            :  * to determine on which node to start looking, as it will for
    3457                 :            :  * certain page cache or slab cache pages such as used for file
    3458                 :            :  * system buffers and inode caches, then instead of starting on the
    3459                 :            :  * local node to look for a free page, rather spread the starting
    3460                 :            :  * node around the tasks mems_allowed nodes.
    3461                 :            :  *
    3462                 :            :  * We don't have to worry about the returned node being offline
    3463                 :            :  * because "it can't happen", and even if it did, it would be ok.
    3464                 :            :  *
    3465                 :            :  * The routines calling guarantee_online_mems() are careful to
    3466                 :            :  * only set nodes in task->mems_allowed that are online.  So it
    3467                 :            :  * should not be possible for the following code to return an
    3468                 :            :  * offline node.  But if it did, that would be ok, as this routine
    3469                 :            :  * is not returning the node where the allocation must be, only
    3470                 :            :  * the node where the search should start.  The zonelist passed to
    3471                 :            :  * __alloc_pages() will include all nodes.  If the slab allocator
    3472                 :            :  * is passed an offline node, it will fall back to the local node.
    3473                 :            :  * See kmem_cache_alloc_node().
    3474                 :            :  */
    3475                 :            : 
    3476                 :          0 : static int cpuset_spread_node(int *rotor)
    3477                 :            : {
    3478                 :          0 :         return *rotor = next_node_in(*rotor, current->mems_allowed);
    3479                 :            : }
    3480                 :            : 
    3481                 :          0 : int cpuset_mem_spread_node(void)
    3482                 :            : {
    3483         [ #  # ]:          0 :         if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE)
    3484                 :          0 :                 current->cpuset_mem_spread_rotor =
    3485                 :          0 :                         node_random(&current->mems_allowed);
    3486                 :            : 
    3487                 :          0 :         return cpuset_spread_node(&current->cpuset_mem_spread_rotor);
    3488                 :            : }
    3489                 :            : 
    3490                 :          0 : int cpuset_slab_spread_node(void)
    3491                 :            : {
    3492         [ #  # ]:          0 :         if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE)
    3493                 :          0 :                 current->cpuset_slab_spread_rotor =
    3494                 :          0 :                         node_random(&current->mems_allowed);
    3495                 :            : 
    3496                 :          0 :         return cpuset_spread_node(&current->cpuset_slab_spread_rotor);
    3497                 :            : }
    3498                 :            : 
    3499                 :            : EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
    3500                 :            : 
    3501                 :            : /**
    3502                 :            :  * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
    3503                 :            :  * @tsk1: pointer to task_struct of some task.
    3504                 :            :  * @tsk2: pointer to task_struct of some other task.
    3505                 :            :  *
    3506                 :            :  * Description: Return true if @tsk1's mems_allowed intersects the
    3507                 :            :  * mems_allowed of @tsk2.  Used by the OOM killer to determine if
    3508                 :            :  * one of the task's memory usage might impact the memory available
    3509                 :            :  * to the other.
    3510                 :            :  **/
    3511                 :            : 
    3512                 :          0 : int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
    3513                 :            :                                    const struct task_struct *tsk2)
    3514                 :            : {
    3515                 :          0 :         return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
    3516                 :            : }
    3517                 :            : 
    3518                 :            : /**
    3519                 :            :  * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed
    3520                 :            :  *
    3521                 :            :  * Description: Prints current's name, cpuset name, and cached copy of its
    3522                 :            :  * mems_allowed to the kernel log.
    3523                 :            :  */
    3524                 :          0 : void cpuset_print_current_mems_allowed(void)
    3525                 :            : {
    3526                 :          0 :         struct cgroup *cgrp;
    3527                 :            : 
    3528                 :          0 :         rcu_read_lock();
    3529                 :            : 
    3530         [ #  # ]:          0 :         cgrp = task_cs(current)->css.cgroup;
    3531                 :          0 :         pr_cont(",cpuset=");
    3532                 :          0 :         pr_cont_cgroup_name(cgrp);
    3533   [ #  #  #  # ]:          0 :         pr_cont(",mems_allowed=%*pbl",
    3534                 :            :                 nodemask_pr_args(&current->mems_allowed));
    3535                 :            : 
    3536                 :          0 :         rcu_read_unlock();
    3537                 :          0 : }
    3538                 :            : 
    3539                 :            : /*
    3540                 :            :  * Collection of memory_pressure is suppressed unless
    3541                 :            :  * this flag is enabled by writing "1" to the special
    3542                 :            :  * cpuset file 'memory_pressure_enabled' in the root cpuset.
    3543                 :            :  */
    3544                 :            : 
    3545                 :            : int cpuset_memory_pressure_enabled __read_mostly;
    3546                 :            : 
    3547                 :            : /**
    3548                 :            :  * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
    3549                 :            :  *
    3550                 :            :  * Keep a running average of the rate of synchronous (direct)
    3551                 :            :  * page reclaim efforts initiated by tasks in each cpuset.
    3552                 :            :  *
    3553                 :            :  * This represents the rate at which some task in the cpuset
    3554                 :            :  * ran low on memory on all nodes it was allowed to use, and
    3555                 :            :  * had to enter the kernels page reclaim code in an effort to
    3556                 :            :  * create more free memory by tossing clean pages or swapping
    3557                 :            :  * or writing dirty pages.
    3558                 :            :  *
    3559                 :            :  * Display to user space in the per-cpuset read-only file
    3560                 :            :  * "memory_pressure".  Value displayed is an integer
    3561                 :            :  * representing the recent rate of entry into the synchronous
    3562                 :            :  * (direct) page reclaim by any task attached to the cpuset.
    3563                 :            :  **/
    3564                 :            : 
    3565                 :          0 : void __cpuset_memory_pressure_bump(void)
    3566                 :            : {
    3567                 :          0 :         rcu_read_lock();
    3568         [ #  # ]:          0 :         fmeter_markevent(&task_cs(current)->fmeter);
    3569                 :          0 :         rcu_read_unlock();
    3570                 :          0 : }
    3571                 :            : 
    3572                 :            : #ifdef CONFIG_PROC_PID_CPUSET
    3573                 :            : /*
    3574                 :            :  * proc_cpuset_show()
    3575                 :            :  *  - Print tasks cpuset path into seq_file.
    3576                 :            :  *  - Used for /proc/<pid>/cpuset.
    3577                 :            :  *  - No need to task_lock(tsk) on this tsk->cpuset reference, as it
    3578                 :            :  *    doesn't really matter if tsk->cpuset changes after we read it,
    3579                 :            :  *    and we take cpuset_mutex, keeping cpuset_attach() from changing it
    3580                 :            :  *    anyway.
    3581                 :            :  */
    3582                 :          0 : int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
    3583                 :            :                      struct pid *pid, struct task_struct *tsk)
    3584                 :            : {
    3585                 :          0 :         char *buf;
    3586                 :          0 :         struct cgroup_subsys_state *css;
    3587                 :          0 :         int retval;
    3588                 :            : 
    3589                 :          0 :         retval = -ENOMEM;
    3590                 :          0 :         buf = kmalloc(PATH_MAX, GFP_KERNEL);
    3591         [ #  # ]:          0 :         if (!buf)
    3592                 :          0 :                 goto out;
    3593                 :            : 
    3594                 :          0 :         css = task_get_css(tsk, cpuset_cgrp_id);
    3595                 :          0 :         retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
    3596                 :          0 :                                 current->nsproxy->cgroup_ns);
    3597         [ #  # ]:          0 :         css_put(css);
    3598         [ #  # ]:          0 :         if (retval >= PATH_MAX)
    3599                 :            :                 retval = -ENAMETOOLONG;
    3600         [ #  # ]:          0 :         if (retval < 0)
    3601                 :          0 :                 goto out_free;
    3602                 :          0 :         seq_puts(m, buf);
    3603                 :          0 :         seq_putc(m, '\n');
    3604                 :          0 :         retval = 0;
    3605                 :          0 : out_free:
    3606                 :          0 :         kfree(buf);
    3607                 :          0 : out:
    3608                 :          0 :         return retval;
    3609                 :            : }
    3610                 :            : #endif /* CONFIG_PROC_PID_CPUSET */
    3611                 :            : 
    3612                 :            : /* Display task mems_allowed in /proc/<pid>/status file. */
    3613                 :        672 : void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
    3614                 :            : {
    3615                 :        672 :         seq_printf(m, "Mems_allowed:\t%*pb\n",
    3616         [ +  - ]:        672 :                    nodemask_pr_args(&task->mems_allowed));
    3617                 :        672 :         seq_printf(m, "Mems_allowed_list:\t%*pbl\n",
    3618                 :            :                    nodemask_pr_args(&task->mems_allowed));
    3619                 :        672 : }

Generated by: LCOV version 1.14