diff options
Diffstat (limited to 'include/linux/cgroup.h')
| -rw-r--r-- | include/linux/cgroup.h | 57 |
1 files changed, 55 insertions, 2 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 81f58b4a5418..0297f930a56e 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -43,6 +43,9 @@ /* walk all threaded css_sets in the domain */ #define CSS_TASK_ITER_THREADED (1U << 1) +/* internal flags */ +#define CSS_TASK_ITER_SKIPPED (1U << 16) + /* a css_task_iter should be treated as an opaque object */ struct css_task_iter { struct cgroup_subsys *ss; @@ -57,6 +60,7 @@ struct css_task_iter { struct list_head *task_pos; struct list_head *tasks_head; struct list_head *mg_tasks_head; + struct list_head *dying_tasks_head; struct css_set *cur_cset; struct css_set *cur_dcset; @@ -487,7 +491,7 @@ static inline struct cgroup_subsys_state *task_css(struct task_struct *task, * * Find the css for the (@task, @subsys_id) combination, increment a * reference on and return it. This function is guaranteed to return a - * valid css. + * valid css. The returned css may already have been offlined. */ static inline struct cgroup_subsys_state * task_get_css(struct task_struct *task, int subsys_id) @@ -497,7 +501,13 @@ task_get_css(struct task_struct *task, int subsys_id) rcu_read_lock(); while (true) { css = task_css(task, subsys_id); - if (likely(css_tryget_online(css))) + /* + * Can't use css_tryget_online() here. A task which has + * PF_EXITING set may stay associated with an offline css. + * If such task calls this function, css_tryget_online() + * will keep failing. + */ + if (likely(css_tryget(css))) break; cpu_relax(); } @@ -881,4 +891,47 @@ static inline void put_cgroup_ns(struct cgroup_namespace *ns) free_cgroup_ns(ns); } +#ifdef CONFIG_CGROUPS + +void cgroup_enter_frozen(void); +void cgroup_leave_frozen(bool always_leave); +void cgroup_update_frozen(struct cgroup *cgrp); +void cgroup_freeze(struct cgroup *cgrp, bool freeze); +void cgroup_freezer_migrate_task(struct task_struct *task, struct cgroup *src, + struct cgroup *dst); + +static inline bool cgroup_task_freeze(struct task_struct *task) +{ + bool ret; + + if (task->flags & PF_KTHREAD) + return false; + + rcu_read_lock(); + ret = test_bit(CGRP_FREEZE, &task_dfl_cgroup(task)->flags); + rcu_read_unlock(); + + return ret; +} + +static inline bool cgroup_task_frozen(struct task_struct *task) +{ + return task->frozen; +} + +#else /* !CONFIG_CGROUPS */ + +static inline void cgroup_enter_frozen(void) { } +static inline void cgroup_leave_frozen(bool always_leave) { } +static inline bool cgroup_task_freeze(struct task_struct *task) +{ + return false; +} +static inline bool cgroup_task_frozen(struct task_struct *task) +{ + return false; +} + +#endif /* !CONFIG_CGROUPS */ + #endif /* _LINUX_CGROUP_H */ |