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-rw-r--r--include/linux/cgroup.h138
1 files changed, 70 insertions, 68 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index eb7ca55f7..cb91b44f5 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -13,10 +13,10 @@
#include <linux/nodemask.h>
#include <linux/rculist.h>
#include <linux/cgroupstats.h>
-#include <linux/rwsem.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/kernfs.h>
+#include <linux/jump_label.h>
#include <linux/cgroup-defs.h>
@@ -41,6 +41,10 @@ struct css_task_iter {
struct list_head *task_pos;
struct list_head *tasks_head;
struct list_head *mg_tasks_head;
+
+ struct css_set *cur_cset;
+ struct task_struct *cur_task;
+ struct list_head iters_node; /* css_set->task_iters */
};
extern struct cgroup_root cgrp_dfl_root;
@@ -50,6 +54,26 @@ extern struct css_set init_css_set;
#include <linux/cgroup_subsys.h>
#undef SUBSYS
+#define SUBSYS(_x) \
+ extern struct static_key_true _x ## _cgrp_subsys_enabled_key; \
+ extern struct static_key_true _x ## _cgrp_subsys_on_dfl_key;
+#include <linux/cgroup_subsys.h>
+#undef SUBSYS
+
+/**
+ * cgroup_subsys_enabled - fast test on whether a subsys is enabled
+ * @ss: subsystem in question
+ */
+#define cgroup_subsys_enabled(ss) \
+ static_branch_likely(&ss ## _enabled_key)
+
+/**
+ * cgroup_subsys_on_dfl - fast test on whether a subsys is on default hierarchy
+ * @ss: subsystem in question
+ */
+#define cgroup_subsys_on_dfl(ss) \
+ static_branch_likely(&ss ## _on_dfl_key)
+
bool css_has_online_children(struct cgroup_subsys_state *css);
struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss);
struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgroup,
@@ -64,6 +88,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
int cgroup_rm_cftypes(struct cftype *cfts);
+void cgroup_file_notify(struct cgroup_file *cfile);
char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry);
@@ -78,6 +103,7 @@ extern void cgroup_cancel_fork(struct task_struct *p,
extern void cgroup_post_fork(struct task_struct *p,
void *old_ss_priv[CGROUP_CANFORK_COUNT]);
void cgroup_exit(struct task_struct *p);
+void cgroup_free(struct task_struct *p);
int cgroup_init_early(void);
int cgroup_init(void);
@@ -94,8 +120,10 @@ struct cgroup_subsys_state *css_rightmost_descendant(struct cgroup_subsys_state
struct cgroup_subsys_state *css_next_descendant_post(struct cgroup_subsys_state *pos,
struct cgroup_subsys_state *css);
-struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset);
-struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset);
+struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
+ struct cgroup_subsys_state **dst_cssp);
+struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
+ struct cgroup_subsys_state **dst_cssp);
void css_task_iter_start(struct cgroup_subsys_state *css,
struct css_task_iter *it);
@@ -210,11 +238,42 @@ void css_task_iter_end(struct css_task_iter *it);
/**
* cgroup_taskset_for_each - iterate cgroup_taskset
* @task: the loop cursor
+ * @dst_css: the destination css
* @tset: taskset to iterate
+ *
+ * @tset may contain multiple tasks and they may belong to multiple
+ * processes.
+ *
+ * On the v2 hierarchy, there may be tasks from multiple processes and they
+ * may not share the source or destination csses.
+ *
+ * On traditional hierarchies, when there are multiple tasks in @tset, if a
+ * task of a process is in @tset, all tasks of the process are in @tset.
+ * Also, all are guaranteed to share the same source and destination csses.
+ *
+ * Iteration is not in any specific order.
+ */
+#define cgroup_taskset_for_each(task, dst_css, tset) \
+ for ((task) = cgroup_taskset_first((tset), &(dst_css)); \
+ (task); \
+ (task) = cgroup_taskset_next((tset), &(dst_css)))
+
+/**
+ * cgroup_taskset_for_each_leader - iterate group leaders in a cgroup_taskset
+ * @leader: the loop cursor
+ * @dst_css: the destination css
+ * @tset: takset to iterate
+ *
+ * Iterate threadgroup leaders of @tset. For single-task migrations, @tset
+ * may not contain any.
*/
-#define cgroup_taskset_for_each(task, tset) \
- for ((task) = cgroup_taskset_first((tset)); (task); \
- (task) = cgroup_taskset_next((tset)))
+#define cgroup_taskset_for_each_leader(leader, dst_css, tset) \
+ for ((leader) = cgroup_taskset_first((tset), &(dst_css)); \
+ (leader); \
+ (leader) = cgroup_taskset_next((tset), &(dst_css))) \
+ if ((leader) != (leader)->group_leader) \
+ ; \
+ else
/*
* Inline functions.
@@ -320,11 +379,11 @@ static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
*/
#ifdef CONFIG_PROVE_RCU
extern struct mutex cgroup_mutex;
-extern struct rw_semaphore css_set_rwsem;
+extern spinlock_t css_set_lock;
#define task_css_set_check(task, __c) \
rcu_dereference_check((task)->cgroups, \
lockdep_is_held(&cgroup_mutex) || \
- lockdep_is_held(&css_set_rwsem) || \
+ lockdep_is_held(&css_set_lock) || \
((task)->flags & PF_EXITING) || (__c))
#else
#define task_css_set_check(task, __c) \
@@ -412,68 +471,10 @@ static inline struct cgroup *task_cgroup(struct task_struct *task,
return task_css(task, subsys_id)->cgroup;
}
-/**
- * cgroup_on_dfl - test whether a cgroup is on the default hierarchy
- * @cgrp: the cgroup of interest
- *
- * The default hierarchy is the v2 interface of cgroup and this function
- * can be used to test whether a cgroup is on the default hierarchy for
- * cases where a subsystem should behave differnetly depending on the
- * interface version.
- *
- * The set of behaviors which change on the default hierarchy are still
- * being determined and the mount option is prefixed with __DEVEL__.
- *
- * List of changed behaviors:
- *
- * - Mount options "noprefix", "xattr", "clone_children", "release_agent"
- * and "name" are disallowed.
- *
- * - When mounting an existing superblock, mount options should match.
- *
- * - Remount is disallowed.
- *
- * - rename(2) is disallowed.
- *
- * - "tasks" is removed. Everything should be at process granularity. Use
- * "cgroup.procs" instead.
- *
- * - "cgroup.procs" is not sorted. pids will be unique unless they got
- * recycled inbetween reads.
- *
- * - "release_agent" and "notify_on_release" are removed. Replacement
- * notification mechanism will be implemented.
- *
- * - "cgroup.clone_children" is removed.
- *
- * - "cgroup.subtree_populated" is available. Its value is 0 if the cgroup
- * and its descendants contain no task; otherwise, 1. The file also
- * generates kernfs notification which can be monitored through poll and
- * [di]notify when the value of the file changes.
- *
- * - cpuset: tasks will be kept in empty cpusets when hotplug happens and
- * take masks of ancestors with non-empty cpus/mems, instead of being
- * moved to an ancestor.
- *
- * - cpuset: a task can be moved into an empty cpuset, and again it takes
- * masks of ancestors.
- *
- * - memcg: use_hierarchy is on by default and the cgroup file for the flag
- * is not created.
- *
- * - blkcg: blk-throttle becomes properly hierarchical.
- *
- * - debug: disallowed on the default hierarchy.
- */
-static inline bool cgroup_on_dfl(const struct cgroup *cgrp)
-{
- return cgrp->root == &cgrp_dfl_root;
-}
-
/* no synchronization, the result can only be used as a hint */
-static inline bool cgroup_has_tasks(struct cgroup *cgrp)
+static inline bool cgroup_is_populated(struct cgroup *cgrp)
{
- return !list_empty(&cgrp->cset_links);
+ return cgrp->populated_cnt;
}
/* returns ino associated with a cgroup */
@@ -546,6 +547,7 @@ static inline void cgroup_cancel_fork(struct task_struct *p,
static inline void cgroup_post_fork(struct task_struct *p,
void *ss_priv[CGROUP_CANFORK_COUNT]) {}
static inline void cgroup_exit(struct task_struct *p) {}
+static inline void cgroup_free(struct task_struct *p) {}
static inline int cgroup_init_early(void) { return 0; }
static inline int cgroup_init(void) { return 0; }