Commit 59676610 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:
 "Just one commit from Steven to take out spin lock from trace event
  handlers"

* 'for-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup/tracing: Move taking of spin lock out of trace event handlers
parents 9022ada8 e4f8d81c
......@@ -53,24 +53,22 @@ DEFINE_EVENT(cgroup_root, cgroup_remount,
DECLARE_EVENT_CLASS(cgroup,
TP_PROTO(struct cgroup *cgrp),
TP_PROTO(struct cgroup *cgrp, const char *path),
TP_ARGS(cgrp),
TP_ARGS(cgrp, path),
TP_STRUCT__entry(
__field( int, root )
__field( int, id )
__field( int, level )
__dynamic_array(char, path,
cgroup_path(cgrp, NULL, 0) + 1)
__string( path, path )
),
TP_fast_assign(
__entry->root = cgrp->root->hierarchy_id;
__entry->id = cgrp->id;
__entry->level = cgrp->level;
cgroup_path(cgrp, __get_dynamic_array(path),
__get_dynamic_array_len(path));
__assign_str(path, path);
),
TP_printk("root=%d id=%d level=%d path=%s",
......@@ -79,45 +77,45 @@ DECLARE_EVENT_CLASS(cgroup,
DEFINE_EVENT(cgroup, cgroup_mkdir,
TP_PROTO(struct cgroup *cgroup),
TP_PROTO(struct cgroup *cgrp, const char *path),
TP_ARGS(cgroup)
TP_ARGS(cgrp, path)
);
DEFINE_EVENT(cgroup, cgroup_rmdir,
TP_PROTO(struct cgroup *cgroup),
TP_PROTO(struct cgroup *cgrp, const char *path),
TP_ARGS(cgroup)
TP_ARGS(cgrp, path)
);
DEFINE_EVENT(cgroup, cgroup_release,
TP_PROTO(struct cgroup *cgroup),
TP_PROTO(struct cgroup *cgrp, const char *path),
TP_ARGS(cgroup)
TP_ARGS(cgrp, path)
);
DEFINE_EVENT(cgroup, cgroup_rename,
TP_PROTO(struct cgroup *cgroup),
TP_PROTO(struct cgroup *cgrp, const char *path),
TP_ARGS(cgroup)
TP_ARGS(cgrp, path)
);
DECLARE_EVENT_CLASS(cgroup_migrate,
TP_PROTO(struct cgroup *dst_cgrp, struct task_struct *task, bool threadgroup),
TP_PROTO(struct cgroup *dst_cgrp, const char *path,
struct task_struct *task, bool threadgroup),
TP_ARGS(dst_cgrp, task, threadgroup),
TP_ARGS(dst_cgrp, path, task, threadgroup),
TP_STRUCT__entry(
__field( int, dst_root )
__field( int, dst_id )
__field( int, dst_level )
__dynamic_array(char, dst_path,
cgroup_path(dst_cgrp, NULL, 0) + 1)
__field( int, pid )
__string( dst_path, path )
__string( comm, task->comm )
),
......@@ -125,8 +123,7 @@ DECLARE_EVENT_CLASS(cgroup_migrate,
__entry->dst_root = dst_cgrp->root->hierarchy_id;
__entry->dst_id = dst_cgrp->id;
__entry->dst_level = dst_cgrp->level;
cgroup_path(dst_cgrp, __get_dynamic_array(dst_path),
__get_dynamic_array_len(dst_path));
__assign_str(dst_path, path);
__entry->pid = task->pid;
__assign_str(comm, task->comm);
),
......@@ -138,16 +135,18 @@ DECLARE_EVENT_CLASS(cgroup_migrate,
DEFINE_EVENT(cgroup_migrate, cgroup_attach_task,
TP_PROTO(struct cgroup *dst_cgrp, struct task_struct *task, bool threadgroup),
TP_PROTO(struct cgroup *dst_cgrp, const char *path,
struct task_struct *task, bool threadgroup),
TP_ARGS(dst_cgrp, task, threadgroup)
TP_ARGS(dst_cgrp, path, task, threadgroup)
);
DEFINE_EVENT(cgroup_migrate, cgroup_transfer_tasks,
TP_PROTO(struct cgroup *dst_cgrp, struct task_struct *task, bool threadgroup),
TP_PROTO(struct cgroup *dst_cgrp, const char *path,
struct task_struct *task, bool threadgroup),
TP_ARGS(dst_cgrp, task, threadgroup)
TP_ARGS(dst_cgrp, path, task, threadgroup)
);
#endif /* _TRACE_CGROUP_H */
......
......@@ -8,6 +8,32 @@
#include <linux/list.h>
#include <linux/refcount.h>
#define TRACE_CGROUP_PATH_LEN 1024
extern spinlock_t trace_cgroup_path_lock;
extern char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
/*
* cgroup_path() takes a spin lock. It is good practice not to take
* spin locks within trace point handlers, as they are mostly hidden
* from normal view. As cgroup_path() can take the kernfs_rename_lock
* spin lock, it is best to not call that function from the trace event
* handler.
*
* Note: trace_cgroup_##type##_enabled() is a static branch that will only
* be set when the trace event is enabled.
*/
#define TRACE_CGROUP_PATH(type, cgrp, ...) \
do { \
if (trace_cgroup_##type##_enabled()) { \
spin_lock(&trace_cgroup_path_lock); \
cgroup_path(cgrp, trace_cgroup_path, \
TRACE_CGROUP_PATH_LEN); \
trace_cgroup_##type(cgrp, trace_cgroup_path, \
##__VA_ARGS__); \
spin_unlock(&trace_cgroup_path_lock); \
} \
} while (0)
/*
* A cgroup can be associated with multiple css_sets as different tasks may
* belong to different cgroups on different hierarchies. In the other
......
......@@ -135,7 +135,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from)
if (task) {
ret = cgroup_migrate(task, false, &mgctx);
if (!ret)
trace_cgroup_transfer_tasks(to, task, false);
TRACE_CGROUP_PATH(transfer_tasks, to, task, false);
put_task_struct(task);
}
} while (task && !ret);
......@@ -865,7 +865,7 @@ static int cgroup1_rename(struct kernfs_node *kn, struct kernfs_node *new_parent
ret = kernfs_rename(kn, new_parent, new_name_str);
if (!ret)
trace_cgroup_rename(cgrp);
TRACE_CGROUP_PATH(rename, cgrp);
mutex_unlock(&cgroup_mutex);
......
......@@ -83,6 +83,9 @@ EXPORT_SYMBOL_GPL(cgroup_mutex);
EXPORT_SYMBOL_GPL(css_set_lock);
#endif
DEFINE_SPINLOCK(trace_cgroup_path_lock);
char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
/*
* Protects cgroup_idr and css_idr so that IDs can be released without
* grabbing cgroup_mutex.
......@@ -2638,7 +2641,7 @@ int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
cgroup_migrate_finish(&mgctx);
if (!ret)
trace_cgroup_attach_task(dst_cgrp, leader, threadgroup);
TRACE_CGROUP_PATH(attach_task, dst_cgrp, leader, threadgroup);
return ret;
}
......@@ -4636,7 +4639,7 @@ static void css_release_work_fn(struct work_struct *work)
struct cgroup *tcgrp;
/* cgroup release path */
trace_cgroup_release(cgrp);
TRACE_CGROUP_PATH(release, cgrp);
if (cgroup_on_dfl(cgrp))
cgroup_rstat_flush(cgrp);
......@@ -4979,7 +4982,7 @@ int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode)
if (ret)
goto out_destroy;
trace_cgroup_mkdir(cgrp);
TRACE_CGROUP_PATH(mkdir, cgrp);
/* let's create and online css's */
kernfs_activate(kn);
......@@ -5167,9 +5170,8 @@ int cgroup_rmdir(struct kernfs_node *kn)
return 0;
ret = cgroup_destroy_locked(cgrp);
if (!ret)
trace_cgroup_rmdir(cgrp);
TRACE_CGROUP_PATH(rmdir, cgrp);
cgroup_kn_unlock(kn);
return ret;
......
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