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Commit fba94807 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup, memcg: move cgroup->event_list[_lock] and event callbacks into memcg 



cgroup_event is being moved from cgroup core to memcg and the
implementation is already moved by the previous patch.  This patch
moves the data fields and callbacks.

* cgroup->event_list[_lock] are moved to mem_cgroup.

* cftype->[un]register_event() are moved to cgroup_event.  This makes
  it impossible for individual cftype definitions to specify their
  event callbacks.  This is worked around by simply hard-coding
  filename to event callback mapping in cgroup_write_event_control().
  This is awkward and inflexible, which is actually desirable given
  that we don't want to grow more usages of this feature.

* eventfd_ctx declaration is removed from cgroup.h, which makes
  vmpressure.h miss eventfd_ctx declaration.  Include eventfd.h from
  vmpressure.h.

v2: Use file name from dentry instead of cftype.  This will allow
    removing all cftype handling in the function.

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>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
parent b5557c4c

include/linux/cgroup.h

+0 −24
Original line number Diff line number Diff line
@@ -29,7 +29,6 @@ struct cgroup_subsys; 
struct inode;

struct cgroup;

struct css_id;

struct eventfd_ctx;



extern int cgroup_init_early(void);

extern int cgroup_init(void);
@@ -239,10 +238,6 @@ struct cgroup { 
	struct rcu_head rcu_head;

	struct work_struct destroy_work;



	/* List of events which userspace want to receive */

	struct list_head event_list;

	spinlock_t event_list_lock;



	/* directory xattrs */

	struct simple_xattrs xattrs;

};
@@ -506,25 +501,6 @@ struct cftype { 
	int (*trigger)(struct cgroup_subsys_state *css, 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_subsys_state *css,

			      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.

	 */

	void (*unregister_event)(struct cgroup_subsys_state *css,

				 struct cftype *cft,

				 struct eventfd_ctx *eventfd);

};



/*

include/linux/vmpressure.h

+1 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/gfp.h>

#include <linux/types.h>

#include <linux/cgroup.h>

#include <linux/eventfd.h>



struct vmpressure {

	unsigned long scanned;

kernel/cgroup.c

+0 −2
Original line number Diff line number Diff line
@@ -1352,8 +1352,6 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp) 
	INIT_LIST_HEAD(&cgrp->pidlists);

	mutex_init(&cgrp->pidlist_mutex);

	cgrp->dummy_css.cgroup = cgrp;

	INIT_LIST_HEAD(&cgrp->event_list);

	spin_lock_init(&cgrp->event_list_lock);

	simple_xattrs_init(&cgrp->xattrs);

}

mm/memcontrol.c

+60 −27
Original line number Diff line number Diff line
@@ -248,6 +248,22 @@ struct cgroup_event { 
	 * Each of these stored in a list by the cgroup.

	 */

	struct list_head list;

	/*

	 * register_event() callback will be used to add new userspace

	 * waiter for changes related to this event.  Use eventfd_signal()

	 * on eventfd to send notification to userspace.

	 */

	int (*register_event)(struct cgroup_subsys_state *css,

			      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 set,

	 * if you want provide notification functionality.

	 */

	void (*unregister_event)(struct cgroup_subsys_state *css,

				 struct cftype *cft,

				 struct eventfd_ctx *eventfd);

	/*

	 * All fields below needed to unregister event when

	 * userspace closes eventfd.
@@ -362,6 +378,10 @@ struct mem_cgroup { 
	atomic_t	numainfo_updating;

#endif



	/* List of events which userspace want to receive */

	struct list_head event_list;

	spinlock_t event_list_lock;



	struct mem_cgroup_per_node *nodeinfo[0];

	/* WARNING: nodeinfo must be the last member here */

};
@@ -5992,7 +6012,7 @@ static void cgroup_event_remove(struct work_struct *work) 


	remove_wait_queue(event->wqh, &event->wait);



	event->cft->unregister_event(css, event->cft, event->eventfd);

	event->unregister_event(css, event->cft, event->eventfd);



	/* Notify userspace the event is going away. */

	eventfd_signal(event->eventfd, 1);
@@ -6012,7 +6032,7 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, 
{

	struct cgroup_event *event = container_of(wait,

			struct cgroup_event, wait);

	struct cgroup *cgrp = event->css->cgroup;

	struct mem_cgroup *memcg = mem_cgroup_from_css(event->css);

	unsigned long flags = (unsigned long)key;



	if (flags & POLLHUP) {
@@ -6025,7 +6045,7 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, 
		 * side will require wqh->lock via remove_wait_queue(),

		 * which we hold.

		 */

		spin_lock(&cgrp->event_list_lock);

		spin_lock(&memcg->event_list_lock);

		if (!list_empty(&event->list)) {

			list_del_init(&event->list);

			/*
@@ -6034,7 +6054,7 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, 
			 */

			schedule_work(&event->remove);

		}

		spin_unlock(&cgrp->event_list_lock);

		spin_unlock(&memcg->event_list_lock);

	}



	return 0;
@@ -6059,12 +6079,13 @@ static void cgroup_event_ptable_queue_proc(struct file *file, 
static int cgroup_write_event_control(struct cgroup_subsys_state *css,

				      struct cftype *cft, const char *buffer)

{

	struct cgroup *cgrp = css->cgroup;

	struct mem_cgroup *memcg = mem_cgroup_from_css(css);

	struct cgroup_event *event;

	struct cgroup_subsys_state *cfile_css;

	unsigned int efd, cfd;

	struct fd efile;

	struct fd cfile;

	const char *name;

	char *endp;

	int ret;
@@ -6118,6 +6139,31 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css, 
		goto out_put_cfile;

	}



	/*

	 * Determine the event callbacks and set them in @event.  This used

	 * 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.

	 */

	name = cfile.file->f_dentry->d_name.name;



	if (!strcmp(name, "memory.usage_in_bytes")) {

		event->register_event = mem_cgroup_usage_register_event;

		event->unregister_event = mem_cgroup_usage_unregister_event;

	} else if (!strcmp(name, "memory.oom_control")) {

		event->register_event = mem_cgroup_oom_register_event;

		event->unregister_event = mem_cgroup_oom_unregister_event;

	} else if (!strcmp(name, "memory.pressure_level")) {

		event->register_event = vmpressure_register_event;

		event->unregister_event = vmpressure_unregister_event;

	} else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {

		event->register_event = mem_cgroup_usage_register_event;

		event->unregister_event = mem_cgroup_usage_unregister_event;

	} else {

		ret = -EINVAL;

		goto out_put_cfile;

	}



	/*

	 * Verify @cfile should belong to @css.  Also, remaining events are

	 * automatically removed on cgroup destruction but the removal is
@@ -6135,21 +6181,15 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css, 
	if (ret)

		goto out_put_cfile;



	if (!event->cft->register_event || !event->cft->unregister_event) {

		ret = -EINVAL;

		goto out_put_css;

	}



	ret = event->cft->register_event(css, event->cft,

			event->eventfd, buffer);

	ret = event->register_event(css, event->cft, event->eventfd, buffer);

	if (ret)

		goto out_put_css;



	efile.file->f_op->poll(efile.file, &event->pt);



	spin_lock(&cgrp->event_list_lock);

	list_add(&event->list, &cgrp->event_list);

	spin_unlock(&cgrp->event_list_lock);

	spin_lock(&memcg->event_list_lock);

	list_add(&event->list, &memcg->event_list);

	spin_unlock(&memcg->event_list_lock);



	fdput(cfile);

	fdput(efile);
@@ -6175,8 +6215,6 @@ static struct cftype mem_cgroup_files[] = { 
		.name = "usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),

		.read = mem_cgroup_read,

		.register_event = mem_cgroup_usage_register_event,

		.unregister_event = mem_cgroup_usage_unregister_event,

	},

	{

		.name = "max_usage_in_bytes",
@@ -6236,14 +6274,10 @@ static struct cftype mem_cgroup_files[] = { 
		.name = "oom_control",

		.read_map = mem_cgroup_oom_control_read,

		.write_u64 = mem_cgroup_oom_control_write,

		.register_event = mem_cgroup_oom_register_event,

		.unregister_event = mem_cgroup_oom_unregister_event,

		.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),

	},

	{

		.name = "pressure_level",

		.register_event = vmpressure_register_event,

		.unregister_event = vmpressure_unregister_event,

	},

#ifdef CONFIG_NUMA

	{
@@ -6291,8 +6325,6 @@ static struct cftype memsw_cgroup_files[] = { 
		.name = "memsw.usage_in_bytes",

		.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),

		.read = mem_cgroup_read,

		.register_event = mem_cgroup_usage_register_event,

		.unregister_event = mem_cgroup_usage_unregister_event,

	},

	{

		.name = "memsw.max_usage_in_bytes",
@@ -6483,6 +6515,8 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 
	mutex_init(&memcg->thresholds_lock);

	spin_lock_init(&memcg->move_lock);

	vmpressure_init(&memcg->vmpressure);

	INIT_LIST_HEAD(&memcg->event_list);

	spin_lock_init(&memcg->event_list_lock);



	return &memcg->css;
@@ -6555,7 +6589,6 @@ 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 *cgrp = css->cgroup;

	struct cgroup_event *event, *tmp;



	/*
@@ -6563,12 +6596,12 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) 
	 * Notify userspace about cgroup removing only after rmdir of cgroup

	 * directory to avoid race between userspace and kernelspace.

	 */

	spin_lock(&cgrp->event_list_lock);

	list_for_each_entry_safe(event, tmp, &cgrp->event_list, list) {

	spin_lock(&memcg->event_list_lock);

	list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {

		list_del_init(&event->list);

		schedule_work(&event->remove);

	}

	spin_unlock(&cgrp->event_list_lock);

	spin_unlock(&memcg->event_list_lock);



	kmem_cgroup_css_offline(memcg);