diff options
Diffstat (limited to 'include/linux/cgroup.h')
| -rw-r--r-- | include/linux/cgroup.h | 58 |
1 files changed, 51 insertions, 7 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 0008dee6651..b8ad1ea9958 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -28,6 +28,7 @@ struct css_id; extern int cgroup_init_early(void); extern int cgroup_init(void); extern void cgroup_lock(void); +extern int cgroup_lock_is_held(void); extern bool cgroup_lock_live_group(struct cgroup *cgrp); extern void cgroup_unlock(void); extern void cgroup_fork(struct task_struct *p); @@ -36,16 +37,24 @@ extern void cgroup_post_fork(struct task_struct *p); extern void cgroup_exit(struct task_struct *p, int run_callbacks); extern int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry); +extern int cgroup_load_subsys(struct cgroup_subsys *ss); +extern void cgroup_unload_subsys(struct cgroup_subsys *ss); extern const struct file_operations proc_cgroup_operations; -/* Define the enumeration of all cgroup subsystems */ +/* Define the enumeration of all builtin cgroup subsystems */ #define SUBSYS(_x) _x ## _subsys_id, enum cgroup_subsys_id { #include <linux/cgroup_subsys.h> - CGROUP_SUBSYS_COUNT + CGROUP_BUILTIN_SUBSYS_COUNT }; #undef SUBSYS +/* + * This define indicates the maximum number of subsystems that can be loaded + * at once. We limit to this many since cgroupfs_root has subsys_bits to keep + * track of all of them. + */ +#define CGROUP_SUBSYS_COUNT (BITS_PER_BYTE*sizeof(unsigned long)) /* Per-subsystem/per-cgroup state maintained by the system. */ struct cgroup_subsys_state { @@ -75,6 +84,12 @@ enum { CSS_REMOVED, /* This CSS is dead */ }; +/* Caller must verify that the css is not for root cgroup */ +static inline void __css_get(struct cgroup_subsys_state *css, int count) +{ + atomic_add(count, &css->refcnt); +} + /* * Call css_get() to hold a reference on the css; it can be used * for a reference obtained via: @@ -86,7 +101,7 @@ static inline void css_get(struct cgroup_subsys_state *css) { /* We don't need to reference count the root state */ if (!test_bit(CSS_ROOT, &css->flags)) - atomic_inc(&css->refcnt); + __css_get(css, 1); } static inline bool css_is_removed(struct cgroup_subsys_state *css) @@ -117,11 +132,11 @@ static inline bool css_tryget(struct cgroup_subsys_state *css) * css_get() or css_tryget() */ -extern void __css_put(struct cgroup_subsys_state *css); +extern void __css_put(struct cgroup_subsys_state *css, int count); static inline void css_put(struct cgroup_subsys_state *css) { if (!test_bit(CSS_ROOT, &css->flags)) - __css_put(css); + __css_put(css, 1); } /* bits in struct cgroup flags field */ @@ -220,6 +235,10 @@ struct cgroup { /* For RCU-protected deletion */ struct rcu_head rcu_head; + + /* List of events which userspace want to recieve */ + struct list_head event_list; + spinlock_t event_list_lock; }; /* @@ -257,7 +276,8 @@ struct css_set { /* * Set of subsystem states, one for each subsystem. This array * is immutable after creation apart from the init_css_set - * during subsystem registration (at boot time). + * during subsystem registration (at boot time) and modular subsystem + * loading/unloading. */ struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; @@ -362,6 +382,23 @@ struct cftype { int (*trigger)(struct cgroup *cgrp, unsigned int event); int (*release)(struct inode *inode, struct file *file); + + /* + * register_event() callback will be used to add new userspace + * waiter for changes related to the cftype. Implement it if + * you want to provide this functionality. Use eventfd_signal() + * on eventfd to send notification to userspace. + */ + int (*register_event)(struct cgroup *cgrp, struct cftype *cft, + struct eventfd_ctx *eventfd, const char *args); + /* + * unregister_event() callback will be called when userspace + * closes the eventfd or on cgroup removing. + * This callback must be implemented, if you want provide + * notification functionality. + */ + int (*unregister_event)(struct cgroup *cgrp, struct cftype *cft, + struct eventfd_ctx *eventfd); }; struct cgroup_scanner { @@ -427,6 +464,8 @@ struct cgroup_subsys { void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp); int (*can_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, struct task_struct *tsk, bool threadgroup); + void (*cancel_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, + struct task_struct *tsk, bool threadgroup); void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp, struct cgroup *old_cgrp, struct task_struct *tsk, bool threadgroup); @@ -471,6 +510,9 @@ struct cgroup_subsys { /* used when use_id == true */ struct idr idr; spinlock_t id_lock; + + /* should be defined only by modular subsystems */ + struct module *module; }; #define SUBSYS(_x) extern struct cgroup_subsys _x ## _subsys; @@ -486,7 +528,9 @@ static inline struct cgroup_subsys_state *cgroup_subsys_state( static inline struct cgroup_subsys_state *task_subsys_state( struct task_struct *task, int subsys_id) { - return rcu_dereference(task->cgroups->subsys[subsys_id]); + return rcu_dereference_check(task->cgroups->subsys[subsys_id], + rcu_read_lock_held() || + cgroup_lock_is_held()); } static inline struct cgroup* task_cgroup(struct task_struct *task, |