Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 3bc942f3 authored by Tejun Heo's avatar Tejun Heo
Browse files

memcg: rename cgroup_event to mem_cgroup_event 



cgroup_event is only available in memcg now.  Let's brand it that way.
While at it, add a comment encouraging deprecation of the feature and
remove the respective section from cgroup documentation.

This patch is cosmetic.

v3: Typo update as per Li Zefan.

v2: Index in cgroups.txt updated accordingly as suggested by Li Zefan.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
parent 59b6f873

Documentation/cgroups/cgroups.txt

+0 −20
Original line number Diff line number Diff line
@@ -24,7 +24,6 @@ CONTENTS: 
  2.1 Basic Usage

  2.2 Attaching processes

  2.3 Mounting hierarchies by name

  2.4 Notification API

3. Kernel API

  3.1 Overview

  3.2 Synchronization
@@ -472,25 +471,6 @@ you give a subsystem a name. 
The name of the subsystem appears as part of the hierarchy description

in /proc/mounts and /proc/<pid>/cgroups.



2.4 Notification API

--------------------



There is mechanism which allows to get notifications about changing

status of a cgroup.



To register a new notification handler you need to:

 - create a file descriptor for event notification using eventfd(2);

 - open a control file to be monitored (e.g. memory.usage_in_bytes);

 - write "<event_fd> <control_fd> <args>" to cgroup.event_control.

   Interpretation of args is defined by control file implementation;



eventfd will be woken up by control file implementation or when the

cgroup is removed.



To unregister a notification handler just close eventfd.



NOTE: Support of notifications should be implemented for the control

file. See documentation for the subsystem.



3. Kernel API

=============

mm/memcontrol.c

+37 −20
Original line number Diff line number Diff line
@@ -231,7 +231,7 @@ struct mem_cgroup_eventfd_list { 
/*

 * cgroup_event represents events which userspace want to receive.

 */

struct cgroup_event {

struct mem_cgroup_event {

	/*

	 * memcg which the event belongs to.

	 */
@@ -6001,15 +6001,28 @@ static void kmem_cgroup_css_offline(struct mem_cgroup *memcg) 
}

#endif



/*

 * DO NOT USE IN NEW FILES.

 *

 * "cgroup.event_control" implementation.

 *

 * This is way over-engineered.  It tries to support fully configurable

 * events for each user.  Such level of flexibility is completely

 * unnecessary especially in the light of the planned unified hierarchy.

 *

 * Please deprecate this and replace with something simpler if at all

 * possible.

 */



/*

 * Unregister event and free resources.

 *

 * Gets called from workqueue.

 */

static void cgroup_event_remove(struct work_struct *work)

static void memcg_event_remove(struct work_struct *work)

{

	struct cgroup_event *event = container_of(work, struct cgroup_event,

			remove);

	struct mem_cgroup_event *event =

		container_of(work, struct mem_cgroup_event, remove);

	struct mem_cgroup *memcg = event->memcg;



	remove_wait_queue(event->wqh, &event->wait);
@@ -6029,11 +6042,11 @@ static void cgroup_event_remove(struct work_struct *work) 
 *

 * Called with wqh->lock held and interrupts disabled.

 */

static int cgroup_event_wake(wait_queue_t *wait, unsigned mode,

static int memcg_event_wake(wait_queue_t *wait, unsigned mode,

			    int sync, void *key)

{

	struct cgroup_event *event = container_of(wait,

			struct cgroup_event, wait);

	struct mem_cgroup_event *event =

		container_of(wait, struct mem_cgroup_event, wait);

	struct mem_cgroup *memcg = event->memcg;

	unsigned long flags = (unsigned long)key;
@@ -6062,27 +6075,29 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, 
	return 0;

}



static void cgroup_event_ptable_queue_proc(struct file *file,

static void memcg_event_ptable_queue_proc(struct file *file,

		wait_queue_head_t *wqh, poll_table *pt)

{

	struct cgroup_event *event = container_of(pt,

			struct cgroup_event, pt);

	struct mem_cgroup_event *event =

		container_of(pt, struct mem_cgroup_event, pt);



	event->wqh = wqh;

	add_wait_queue(wqh, &event->wait);

}



/*

 * DO NOT USE IN NEW FILES.

 *

 * Parse input and register new cgroup event handler.

 *

 * Input must be in format '<event_fd> <control_fd> <args>'.

 * Interpretation of args is defined by control file implementation.

 */

static int cgroup_write_event_control(struct cgroup_subsys_state *css,

static int memcg_write_event_control(struct cgroup_subsys_state *css,

				     struct cftype *cft, const char *buffer)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(css);

	struct cgroup_event *event;

	struct mem_cgroup_event *event;

	struct cgroup_subsys_state *cfile_css;

	unsigned int efd, cfd;

	struct fd efile;
@@ -6107,9 +6122,9 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css, 


	event->memcg = memcg;

	INIT_LIST_HEAD(&event->list);

	init_poll_funcptr(&event->pt, cgroup_event_ptable_queue_proc);

	init_waitqueue_func_entry(&event->wait, cgroup_event_wake);

	INIT_WORK(&event->remove, cgroup_event_remove);

	init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);

	init_waitqueue_func_entry(&event->wait, memcg_event_wake);

	INIT_WORK(&event->remove, memcg_event_remove);



	efile = fdget(efd);

	if (!efile.file) {
@@ -6140,6 +6155,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css, 
	 * to be done via struct cftype but cgroup core no longer knows

	 * about these events.  The following is crude but the whole thing

	 * is for compatibility anyway.

	 *

	 * DO NOT ADD NEW FILES.

	 */

	name = cfile.file->f_dentry->d_name.name;
@@ -6251,8 +6268,8 @@ static struct cftype mem_cgroup_files[] = { 
		.read_u64 = mem_cgroup_hierarchy_read,

	},

	{

		.name = "cgroup.event_control",

		.write_string = cgroup_write_event_control,

		.name = "cgroup.event_control",		/* XXX: for compat */

		.write_string = memcg_write_event_control,

		.flags = CFTYPE_NO_PREFIX,

		.mode = S_IWUGO,

	},
@@ -6585,7 +6602,7 @@ static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg) 
static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)

{

	struct mem_cgroup *memcg = mem_cgroup_from_css(css);

	struct cgroup_event *event, *tmp;

	struct mem_cgroup_event *event, *tmp;



	/*

	 * Unregister events and notify userspace.