extern int cgroupstats_build(struct cgroupstats *stats,
struct dentry *dentry);
-extern struct file_operations proc_cgroup_operations;
+extern const struct file_operations proc_cgroup_operations;
/* Define the enumeration of all cgroup subsystems */
#define SUBSYS(_x) _x ## _subsys_id,
CGRP_WAIT_ON_RMDIR,
};
+/* which pidlist file are we talking about? */
+enum cgroup_filetype {
+ CGROUP_FILE_PROCS,
+ CGROUP_FILE_TASKS,
+};
+
+/*
+ * A pidlist is a list of pids that virtually represents the contents of one
+ * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists,
+ * a pair (one each for procs, tasks) for each pid namespace that's relevant
+ * to the cgroup.
+ */
+struct cgroup_pidlist {
+ /*
+ * used to find which pidlist is wanted. doesn't change as long as
+ * this particular list stays in the list.
+ */
+ struct { enum cgroup_filetype type; struct pid_namespace *ns; } key;
+ /* array of xids */
+ pid_t *list;
+ /* how many elements the above list has */
+ int length;
+ /* how many files are using the current array */
+ int use_count;
+ /* each of these stored in a list by its cgroup */
+ struct list_head links;
+ /* pointer to the cgroup we belong to, for list removal purposes */
+ struct cgroup *owner;
+ /* protects the other fields */
+ struct rw_semaphore mutex;
+};
+
struct cgroup {
unsigned long flags; /* "unsigned long" so bitops work */
*/
struct list_head release_list;
- /* pids_mutex protects the fields below */
- struct rw_semaphore pids_mutex;
- /* Array of process ids in the cgroup */
- pid_t *tasks_pids;
- /* How many files are using the current tasks_pids array */
- int pids_use_count;
- /* Length of the current tasks_pids array */
- int pids_length;
+ /*
+ * list of pidlists, up to two for each namespace (one for procs, one
+ * for tasks); created on demand.
+ */
+ struct list_head pidlists;
+ struct mutex pidlist_mutex;
/* For RCU-protected deletion */
struct rcu_head rcu_head;
* during subsystem registration (at boot time).
*/
struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
+
+ /* For RCU-protected deletion */
+ struct rcu_head rcu_head;
};
/*
*/
char name[MAX_CFTYPE_NAME];
int private;
+ /*
+ * If not 0, file mode is set to this value, otherwise it will
+ * be figured out automatically
+ */
+ mode_t mode;
/*
* If non-zero, defines the maximum length of string that can
void (*process_task)(struct task_struct *p,
struct cgroup_scanner *scan);
struct ptr_heap *heap;
+ void *data;
};
/*
/* Return true if cgrp is a descendant of the task's cgroup */
int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task);
-/* Control Group subsystem type. See Documentation/cgroups.txt for details */
+/*
+ * When the subsys has to access css and may add permanent refcnt to css,
+ * it should take care of racy conditions with rmdir(). Following set of
+ * functions, is for stop/restart rmdir if necessary.
+ * Because these will call css_get/put, "css" should be alive css.
+ *
+ * cgroup_exclude_rmdir();
+ * ...do some jobs which may access arbitrary empty cgroup
+ * cgroup_release_and_wakeup_rmdir();
+ *
+ * When someone removes a cgroup while cgroup_exclude_rmdir() holds it,
+ * it sleeps and cgroup_release_and_wakeup_rmdir() will wake him up.
+ */
+
+void cgroup_exclude_rmdir(struct cgroup_subsys_state *css);
+void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css);
+
+/*
+ * Control Group subsystem type.
+ * See Documentation/cgroups/cgroups.txt for details
+ */
struct cgroup_subsys {
struct cgroup_subsys_state *(*create)(struct cgroup_subsys *ss,
struct cgroup *cgrp);
int (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
- int (*can_attach)(struct cgroup_subsys *ss,
- struct cgroup *cgrp, struct task_struct *tsk);
+ int (*can_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);
+ struct cgroup *old_cgrp, struct task_struct *tsk,
+ bool threadgroup);
void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
void (*exit)(struct cgroup_subsys *ss, struct task_struct *task);
int (*populate)(struct cgroup_subsys *ss,
/* Returns true if root is ancestor of cg */
bool css_is_ancestor(struct cgroup_subsys_state *cg,
- struct cgroup_subsys_state *root);
+ const struct cgroup_subsys_state *root);
/* Get id and depth of css */
unsigned short css_id(struct cgroup_subsys_state *css);