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Commit b4c2b231 authored by Kirill Tkhai's avatar Kirill Tkhai Committed by Linus Torvalds
Browse files

mm: assign id to every memcg-aware shrinker 

Introduce shrinker::id number, which is used to enumerate memcg-aware
shrinkers.  The number start from 0, and the code tries to maintain it
as small as possible.

This will be used to represent a memcg-aware shrinkers in memcg
shrinkers map.

Since all memcg-aware shrinkers are based on list_lru, which is
per-memcg in case of !CONFIG_MEMCG_KMEM only, the new functionality will
be under this config option.

[ktkhai@virtuozzo.com: v9]
  Link: http://lkml.kernel.org/r/153112546435.4097.10607140323811756557.stgit@localhost.localdomain
Link: http://lkml.kernel.org/r/153063054586.1818.6041047871606697364.stgit@localhost.localdomain


Signed-off-by: default avatarKirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: default avatarVladimir Davydov <vdavydov.dev@gmail.com>
Tested-by: default avatarShakeel Butt <shakeelb@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Li RongQing <lirongqing@baidu.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Sahitya Tummala <stummala@codeaurora.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 84c07d11

include/linux/shrinker.h

+4 −0
Original line number Diff line number Diff line
@@ -66,6 +66,10 @@ struct shrinker { 


	/* These are for internal use */

	struct list_head list;

#ifdef CONFIG_MEMCG_KMEM

	/* ID in shrinker_idr */

	int id;

#endif

	/* objs pending delete, per node */

	atomic_long_t *nr_deferred;

};

mm/vmscan.c

+63 −0
Original line number Diff line number Diff line
@@ -169,6 +169,50 @@ unsigned long vm_total_pages; 
static LIST_HEAD(shrinker_list);

static DECLARE_RWSEM(shrinker_rwsem);



#ifdef CONFIG_MEMCG_KMEM

static DEFINE_IDR(shrinker_idr);

static int shrinker_nr_max;



static int prealloc_memcg_shrinker(struct shrinker *shrinker)

{

	int id, ret = -ENOMEM;



	down_write(&shrinker_rwsem);

	/* This may call shrinker, so it must use down_read_trylock() */

	id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL);

	if (id < 0)

		goto unlock;



	if (id >= shrinker_nr_max)

		shrinker_nr_max = id + 1;

	shrinker->id = id;

	ret = 0;

unlock:

	up_write(&shrinker_rwsem);

	return ret;

}



static void unregister_memcg_shrinker(struct shrinker *shrinker)

{

	int id = shrinker->id;



	BUG_ON(id < 0);



	down_write(&shrinker_rwsem);

	idr_remove(&shrinker_idr, id);

	up_write(&shrinker_rwsem);

}

#else /* CONFIG_MEMCG_KMEM */

static int prealloc_memcg_shrinker(struct shrinker *shrinker)

{

	return 0;

}



static void unregister_memcg_shrinker(struct shrinker *shrinker)

{

}

#endif /* CONFIG_MEMCG_KMEM */



#ifdef CONFIG_MEMCG

static bool global_reclaim(struct scan_control *sc)

{
@@ -313,11 +357,28 @@ int prealloc_shrinker(struct shrinker *shrinker) 
	shrinker->nr_deferred = kzalloc(size, GFP_KERNEL);

	if (!shrinker->nr_deferred)

		return -ENOMEM;



	if (shrinker->flags & SHRINKER_MEMCG_AWARE) {

		if (prealloc_memcg_shrinker(shrinker))

			goto free_deferred;

	}



	return 0;



free_deferred:

	kfree(shrinker->nr_deferred);

	shrinker->nr_deferred = NULL;

	return -ENOMEM;

}



void free_prealloced_shrinker(struct shrinker *shrinker)

{

	if (!shrinker->nr_deferred)

		return;



	if (shrinker->flags & SHRINKER_MEMCG_AWARE)

		unregister_memcg_shrinker(shrinker);



	kfree(shrinker->nr_deferred);

	shrinker->nr_deferred = NULL;

}
@@ -347,6 +408,8 @@ void unregister_shrinker(struct shrinker *shrinker) 
{

	if (!shrinker->nr_deferred)

		return;

	if (shrinker->flags & SHRINKER_MEMCG_AWARE)

		unregister_memcg_shrinker(shrinker);

	down_write(&shrinker_rwsem);

	list_del(&shrinker->list);

	up_write(&shrinker_rwsem);