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Commit c9fc5864 authored by Tejun Heo's avatar Tejun Heo Committed by Linus Torvalds
Browse files

slab: introduce __kmemcg_cache_deactivate() 

__kmem_cache_shrink() is called with %true @deactivate only for memcg
caches.  Remove @deactivate from __kmem_cache_shrink() and introduce
__kmemcg_cache_deactivate() instead.  Each memcg-supporting allocator
should implement it and it should deactivate and drain the cache.

This is to allow memcg cache deactivation behavior to further deviate
from simple shrinking without messing up __kmem_cache_shrink().

This is pure reorganization and doesn't introduce any observable
behavior changes.

v2: Dropped unnecessary ifdef in mm/slab.h as suggested by Vladimir.

Link: http://lkml.kernel.org/r/20170117235411.9408-8-tj@kernel.org


Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarVladimir Davydov <vdavydov.dev@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 510ded33

mm/slab.c

+9 −2
Original line number Diff line number Diff line
@@ -2315,7 +2315,7 @@ static int drain_freelist(struct kmem_cache *cache, 
	return nr_freed;

}



int __kmem_cache_shrink(struct kmem_cache *cachep, bool deactivate)

int __kmem_cache_shrink(struct kmem_cache *cachep)

{

	int ret = 0;

	int node;
@@ -2333,9 +2333,16 @@ int __kmem_cache_shrink(struct kmem_cache *cachep, bool deactivate) 
	return (ret ? 1 : 0);

}



#ifdef CONFIG_MEMCG

void __kmemcg_cache_deactivate(struct kmem_cache *cachep)

{

	__kmem_cache_shrink(cachep);

}

#endif



int __kmem_cache_shutdown(struct kmem_cache *cachep)

{

	return __kmem_cache_shrink(cachep, false);

	return __kmem_cache_shrink(cachep);

}



void __kmem_cache_release(struct kmem_cache *cachep)

mm/slab.h

+2 −1
Original line number Diff line number Diff line
@@ -167,7 +167,8 @@ static inline unsigned long kmem_cache_flags(unsigned long object_size, 


int __kmem_cache_shutdown(struct kmem_cache *);

void __kmem_cache_release(struct kmem_cache *);

int __kmem_cache_shrink(struct kmem_cache *, bool);

int __kmem_cache_shrink(struct kmem_cache *);

void __kmemcg_cache_deactivate(struct kmem_cache *s);

void slab_kmem_cache_release(struct kmem_cache *);



struct seq_file;

mm/slab_common.c

+2 −2
Original line number Diff line number Diff line
@@ -646,7 +646,7 @@ void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) 
		if (!c)

			continue;



		__kmem_cache_shrink(c, true);

		__kmemcg_cache_deactivate(c);

		arr->entries[idx] = NULL;

	}

	mutex_unlock(&slab_mutex);
@@ -794,7 +794,7 @@ int kmem_cache_shrink(struct kmem_cache *cachep) 
	get_online_cpus();

	get_online_mems();

	kasan_cache_shrink(cachep);

	ret = __kmem_cache_shrink(cachep, false);

	ret = __kmem_cache_shrink(cachep);

	put_online_mems();

	put_online_cpus();

	return ret;

mm/slob.c

+1 −1
Original line number Diff line number Diff line
@@ -634,7 +634,7 @@ void __kmem_cache_release(struct kmem_cache *c) 
{

}



int __kmem_cache_shrink(struct kmem_cache *d, bool deactivate)

int __kmem_cache_shrink(struct kmem_cache *d)

{

	return 0;

}

mm/slub.c

+22 −17
Original line number Diff line number Diff line
@@ -3894,7 +3894,7 @@ EXPORT_SYMBOL(kfree); 
 * being allocated from last increasing the chance that the last objects

 * are freed in them.

 */

int __kmem_cache_shrink(struct kmem_cache *s, bool deactivate)

int __kmem_cache_shrink(struct kmem_cache *s)

{

	int node;

	int i;
@@ -3906,21 +3906,6 @@ int __kmem_cache_shrink(struct kmem_cache *s, bool deactivate) 
	unsigned long flags;

	int ret = 0;



	if (deactivate) {

		/*

		 * Disable empty slabs caching. Used to avoid pinning offline

		 * memory cgroups by kmem pages that can be freed.

		 */

		s->cpu_partial = 0;

		s->min_partial = 0;



		/*

		 * s->cpu_partial is checked locklessly (see put_cpu_partial),

		 * so we have to make sure the change is visible.

		 */

		synchronize_sched();

	}



	flush_all(s);

	for_each_kmem_cache_node(s, node, n) {

		INIT_LIST_HEAD(&discard);
@@ -3971,13 +3956,33 @@ int __kmem_cache_shrink(struct kmem_cache *s, bool deactivate) 
	return ret;

}



#ifdef CONFIG_MEMCG

void __kmemcg_cache_deactivate(struct kmem_cache *s)

{

	/*

	 * Disable empty slabs caching. Used to avoid pinning offline

	 * memory cgroups by kmem pages that can be freed.

	 */

	s->cpu_partial = 0;

	s->min_partial = 0;



	/*

	 * s->cpu_partial is checked locklessly (see put_cpu_partial), so

	 * we have to make sure the change is visible.

	 */

	synchronize_sched();



	__kmem_cache_shrink(s);

}

#endif



static int slab_mem_going_offline_callback(void *arg)

{

	struct kmem_cache *s;



	mutex_lock(&slab_mutex);

	list_for_each_entry(s, &slab_caches, list)

		__kmem_cache_shrink(s, false);

		__kmem_cache_shrink(s);

	mutex_unlock(&slab_mutex);



	return 0;