LCOV - code coverage report
Current view: top level - kernel/cgroup - cgroup-internal.h (source / functions) Hit Total Coverage
Test: Real Lines: 8 9 88.9 %
Date: 2020-10-17 15:46:16 Functions: 0 1 0.0 %
Legend: Neither, QEMU, Real, Both Branches: 0 0 -

           Branch data     Line data    Source code
       1                 :            : /* SPDX-License-Identifier: GPL-2.0 */
       2                 :            : #ifndef __CGROUP_INTERNAL_H
       3                 :            : #define __CGROUP_INTERNAL_H
       4                 :            : 
       5                 :            : #include <linux/cgroup.h>
       6                 :            : #include <linux/kernfs.h>
       7                 :            : #include <linux/workqueue.h>
       8                 :            : #include <linux/list.h>
       9                 :            : #include <linux/refcount.h>
      10                 :            : #include <linux/fs_context.h>
      11                 :            : 
      12                 :            : #define TRACE_CGROUP_PATH_LEN 1024
      13                 :            : extern spinlock_t trace_cgroup_path_lock;
      14                 :            : extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
      15                 :            : extern bool cgroup_debug;
      16                 :            : extern void __init enable_debug_cgroup(void);
      17                 :            : 
      18                 :            : /*
      19                 :            :  * cgroup_path() takes a spin lock. It is good practice not to take
      20                 :            :  * spin locks within trace point handlers, as they are mostly hidden
      21                 :            :  * from normal view. As cgroup_path() can take the kernfs_rename_lock
      22                 :            :  * spin lock, it is best to not call that function from the trace event
      23                 :            :  * handler.
      24                 :            :  *
      25                 :            :  * Note: trace_cgroup_##type##_enabled() is a static branch that will only
      26                 :            :  *       be set when the trace event is enabled.
      27                 :            :  */
      28                 :            : #define TRACE_CGROUP_PATH(type, cgrp, ...)                              \
      29                 :            :         do {                                                            \
      30                 :            :                 if (trace_cgroup_##type##_enabled()) {                  \
      31                 :            :                         unsigned long flags;                            \
      32                 :            :                         spin_lock_irqsave(&trace_cgroup_path_lock,  \
      33                 :            :                                           flags);                       \
      34                 :            :                         cgroup_path(cgrp, trace_cgroup_path,            \
      35                 :            :                                     TRACE_CGROUP_PATH_LEN);             \
      36                 :            :                         trace_cgroup_##type(cgrp, trace_cgroup_path,    \
      37                 :            :                                             ##__VA_ARGS__);             \
      38                 :            :                         spin_unlock_irqrestore(&trace_cgroup_path_lock, \
      39                 :            :                                                flags);                  \
      40                 :            :                 }                                                       \
      41                 :            :         } while (0)
      42                 :            : 
      43                 :            : /*
      44                 :            :  * The cgroup filesystem superblock creation/mount context.
      45                 :            :  */
      46                 :            : struct cgroup_fs_context {
      47                 :            :         struct kernfs_fs_context kfc;
      48                 :            :         struct cgroup_root      *root;
      49                 :            :         struct cgroup_namespace *ns;
      50                 :            :         unsigned int    flags;                  /* CGRP_ROOT_* flags */
      51                 :            : 
      52                 :            :         /* cgroup1 bits */
      53                 :            :         bool            cpuset_clone_children;
      54                 :            :         bool            none;                   /* User explicitly requested empty subsystem */
      55                 :            :         bool            all_ss;                 /* Seen 'all' option */
      56                 :            :         u16             subsys_mask;            /* Selected subsystems */
      57                 :            :         char            *name;                  /* Hierarchy name */
      58                 :            :         char            *release_agent;         /* Path for release notifications */
      59                 :            : };
      60                 :            : 
      61                 :            : static inline struct cgroup_fs_context *cgroup_fc2context(struct fs_context *fc)
      62                 :            : {
      63                 :          3 :         struct kernfs_fs_context *kfc = fc->fs_private;
      64                 :            : 
      65                 :            :         return container_of(kfc, struct cgroup_fs_context, kfc);
      66                 :            : }
      67                 :            : 
      68                 :            : /*
      69                 :            :  * A cgroup can be associated with multiple css_sets as different tasks may
      70                 :            :  * belong to different cgroups on different hierarchies.  In the other
      71                 :            :  * direction, a css_set is naturally associated with multiple cgroups.
      72                 :            :  * This M:N relationship is represented by the following link structure
      73                 :            :  * which exists for each association and allows traversing the associations
      74                 :            :  * from both sides.
      75                 :            :  */
      76                 :            : struct cgrp_cset_link {
      77                 :            :         /* the cgroup and css_set this link associates */
      78                 :            :         struct cgroup           *cgrp;
      79                 :            :         struct css_set          *cset;
      80                 :            : 
      81                 :            :         /* list of cgrp_cset_links anchored at cgrp->cset_links */
      82                 :            :         struct list_head        cset_link;
      83                 :            : 
      84                 :            :         /* list of cgrp_cset_links anchored at css_set->cgrp_links */
      85                 :            :         struct list_head        cgrp_link;
      86                 :            : };
      87                 :            : 
      88                 :            : /* used to track tasks and csets during migration */
      89                 :            : struct cgroup_taskset {
      90                 :            :         /* the src and dst cset list running through cset->mg_node */
      91                 :            :         struct list_head        src_csets;
      92                 :            :         struct list_head        dst_csets;
      93                 :            : 
      94                 :            :         /* the number of tasks in the set */
      95                 :            :         int                     nr_tasks;
      96                 :            : 
      97                 :            :         /* the subsys currently being processed */
      98                 :            :         int                     ssid;
      99                 :            : 
     100                 :            :         /*
     101                 :            :          * Fields for cgroup_taskset_*() iteration.
     102                 :            :          *
     103                 :            :          * Before migration is committed, the target migration tasks are on
     104                 :            :          * ->mg_tasks of the csets on ->src_csets.  After, on ->mg_tasks of
     105                 :            :          * the csets on ->dst_csets.  ->csets point to either ->src_csets
     106                 :            :          * or ->dst_csets depending on whether migration is committed.
     107                 :            :          *
     108                 :            :          * ->cur_csets and ->cur_task point to the current task position
     109                 :            :          * during iteration.
     110                 :            :          */
     111                 :            :         struct list_head        *csets;
     112                 :            :         struct css_set          *cur_cset;
     113                 :            :         struct task_struct      *cur_task;
     114                 :            : };
     115                 :            : 
     116                 :            : /* migration context also tracks preloading */
     117                 :            : struct cgroup_mgctx {
     118                 :            :         /*
     119                 :            :          * Preloaded source and destination csets.  Used to guarantee
     120                 :            :          * atomic success or failure on actual migration.
     121                 :            :          */
     122                 :            :         struct list_head        preloaded_src_csets;
     123                 :            :         struct list_head        preloaded_dst_csets;
     124                 :            : 
     125                 :            :         /* tasks and csets to migrate */
     126                 :            :         struct cgroup_taskset   tset;
     127                 :            : 
     128                 :            :         /* subsystems affected by migration */
     129                 :            :         u16                     ss_mask;
     130                 :            : };
     131                 :            : 
     132                 :            : #define CGROUP_TASKSET_INIT(tset)                                               \
     133                 :            : {                                                                               \
     134                 :            :         .src_csets              = LIST_HEAD_INIT(tset.src_csets),               \
     135                 :            :         .dst_csets              = LIST_HEAD_INIT(tset.dst_csets),               \
     136                 :            :         .csets                  = &tset.src_csets,                          \
     137                 :            : }
     138                 :            : 
     139                 :            : #define CGROUP_MGCTX_INIT(name)                                                 \
     140                 :            : {                                                                               \
     141                 :            :         LIST_HEAD_INIT(name.preloaded_src_csets),                               \
     142                 :            :         LIST_HEAD_INIT(name.preloaded_dst_csets),                               \
     143                 :            :         CGROUP_TASKSET_INIT(name.tset),                                         \
     144                 :            : }
     145                 :            : 
     146                 :            : #define DEFINE_CGROUP_MGCTX(name)                                               \
     147                 :            :         struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
     148                 :            : 
     149                 :            : extern struct mutex cgroup_mutex;
     150                 :            : extern spinlock_t css_set_lock;
     151                 :            : extern struct cgroup_subsys *cgroup_subsys[];
     152                 :            : extern struct list_head cgroup_roots;
     153                 :            : extern struct file_system_type cgroup_fs_type;
     154                 :            : 
     155                 :            : /* iterate across the hierarchies */
     156                 :            : #define for_each_root(root)                                             \
     157                 :            :         list_for_each_entry((root), &cgroup_roots, root_list)
     158                 :            : 
     159                 :            : /**
     160                 :            :  * for_each_subsys - iterate all enabled cgroup subsystems
     161                 :            :  * @ss: the iteration cursor
     162                 :            :  * @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
     163                 :            :  */
     164                 :            : #define for_each_subsys(ss, ssid)                                       \
     165                 :            :         for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT &&             \
     166                 :            :              (((ss) = cgroup_subsys[ssid]) || true); (ssid)++)
     167                 :            : 
     168                 :            : static inline bool cgroup_is_dead(const struct cgroup *cgrp)
     169                 :            : {
     170                 :          3 :         return !(cgrp->self.flags & CSS_ONLINE);
     171                 :            : }
     172                 :            : 
     173                 :            : static inline bool notify_on_release(const struct cgroup *cgrp)
     174                 :            : {
     175                 :          0 :         return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
     176                 :            : }
     177                 :            : 
     178                 :            : void put_css_set_locked(struct css_set *cset);
     179                 :            : 
     180                 :          3 : static inline void put_css_set(struct css_set *cset)
     181                 :            : {
     182                 :            :         unsigned long flags;
     183                 :            : 
     184                 :            :         /*
     185                 :            :          * Ensure that the refcount doesn't hit zero while any readers
     186                 :            :          * can see it. Similar to atomic_dec_and_lock(), but for an
     187                 :            :          * rwlock
     188                 :            :          */
     189                 :          3 :         if (refcount_dec_not_one(&cset->refcount))
     190                 :          3 :                 return;
     191                 :            : 
     192                 :          3 :         spin_lock_irqsave(&css_set_lock, flags);
     193                 :          3 :         put_css_set_locked(cset);
     194                 :            :         spin_unlock_irqrestore(&css_set_lock, flags);
     195                 :            : }
     196                 :            : 
     197                 :            : /*
     198                 :            :  * refcounted get/put for css_set objects
     199                 :            :  */
     200                 :            : static inline void get_css_set(struct css_set *cset)
     201                 :            : {
     202                 :          3 :         refcount_inc(&cset->refcount);
     203                 :            : }
     204                 :            : 
     205                 :            : bool cgroup_ssid_enabled(int ssid);
     206                 :            : bool cgroup_on_dfl(const struct cgroup *cgrp);
     207                 :            : bool cgroup_is_thread_root(struct cgroup *cgrp);
     208                 :            : bool cgroup_is_threaded(struct cgroup *cgrp);
     209                 :            : 
     210                 :            : struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root);
     211                 :            : struct cgroup *task_cgroup_from_root(struct task_struct *task,
     212                 :            :                                      struct cgroup_root *root);
     213                 :            : struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline);
     214                 :            : void cgroup_kn_unlock(struct kernfs_node *kn);
     215                 :            : int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
     216                 :            :                           struct cgroup_namespace *ns);
     217                 :            : 
     218                 :            : void cgroup_free_root(struct cgroup_root *root);
     219                 :            : void init_cgroup_root(struct cgroup_fs_context *ctx);
     220                 :            : int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
     221                 :            : int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
     222                 :            : int cgroup_do_get_tree(struct fs_context *fc);
     223                 :            : 
     224                 :            : int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp);
     225                 :            : void cgroup_migrate_finish(struct cgroup_mgctx *mgctx);
     226                 :            : void cgroup_migrate_add_src(struct css_set *src_cset, struct cgroup *dst_cgrp,
     227                 :            :                             struct cgroup_mgctx *mgctx);
     228                 :            : int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx);
     229                 :            : int cgroup_migrate(struct task_struct *leader, bool threadgroup,
     230                 :            :                    struct cgroup_mgctx *mgctx);
     231                 :            : 
     232                 :            : int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
     233                 :            :                        bool threadgroup);
     234                 :            : struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup)
     235                 :            :         __acquires(&cgroup_threadgroup_rwsem);
     236                 :            : void cgroup_procs_write_finish(struct task_struct *task)
     237                 :            :         __releases(&cgroup_threadgroup_rwsem);
     238                 :            : 
     239                 :            : void cgroup_lock_and_drain_offline(struct cgroup *cgrp);
     240                 :            : 
     241                 :            : int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode);
     242                 :            : int cgroup_rmdir(struct kernfs_node *kn);
     243                 :            : int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
     244                 :            :                      struct kernfs_root *kf_root);
     245                 :            : 
     246                 :            : int __cgroup_task_count(const struct cgroup *cgrp);
     247                 :            : int cgroup_task_count(const struct cgroup *cgrp);
     248                 :            : 
     249                 :            : /*
     250                 :            :  * rstat.c
     251                 :            :  */
     252                 :            : int cgroup_rstat_init(struct cgroup *cgrp);
     253                 :            : void cgroup_rstat_exit(struct cgroup *cgrp);
     254                 :            : void cgroup_rstat_boot(void);
     255                 :            : void cgroup_base_stat_cputime_show(struct seq_file *seq);
     256                 :            : 
     257                 :            : /*
     258                 :            :  * namespace.c
     259                 :            :  */
     260                 :            : extern const struct proc_ns_operations cgroupns_operations;
     261                 :            : 
     262                 :            : /*
     263                 :            :  * cgroup-v1.c
     264                 :            :  */
     265                 :            : extern struct cftype cgroup1_base_files[];
     266                 :            : extern struct kernfs_syscall_ops cgroup1_kf_syscall_ops;
     267                 :            : extern const struct fs_parameter_description cgroup1_fs_parameters;
     268                 :            : 
     269                 :            : int proc_cgroupstats_show(struct seq_file *m, void *v);
     270                 :            : bool cgroup1_ssid_disabled(int ssid);
     271                 :            : void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
     272                 :            : void cgroup1_release_agent(struct work_struct *work);
     273                 :            : void cgroup1_check_for_release(struct cgroup *cgrp);
     274                 :            : int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param);
     275                 :            : int cgroup1_get_tree(struct fs_context *fc);
     276                 :            : int cgroup1_reconfigure(struct fs_context *ctx);
     277                 :            : 
     278                 :            : #endif /* __CGROUP_INTERNAL_H */
    

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