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Commit 49dfc304 authored by Joonsoo Kim's avatar Joonsoo Kim Committed by Linus Torvalds
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slab: use the lock on alien_cache, instead of the lock on array_cache 



Now, we have separate alien_cache structure, so it'd be better to hold
the lock on alien_cache while manipulating alien_cache.  After that, we
don't need the lock on array_cache, so remove it.

Signed-off-by: default avatarJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: default avatarChristoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c8522a3a

mm/slab.c

+8 −17
Original line number Diff line number Diff line
@@ -191,7 +191,6 @@ struct array_cache { 
	unsigned int limit;

	unsigned int batchcount;

	unsigned int touched;

	spinlock_t lock;

	void *entry[];	/*

			 * Must have this definition in here for the proper

			 * alignment of array_cache. Also simplifies accessing
@@ -512,7 +511,7 @@ static void slab_set_lock_classes(struct kmem_cache *cachep, 
		return;

	for_each_node(r) {

		if (alc[r])

			lockdep_set_class(&(alc[r]->ac.lock), alc_key);

			lockdep_set_class(&(alc[r]->lock), alc_key);

	}

}
@@ -811,7 +810,6 @@ static void init_arraycache(struct array_cache *ac, int limit, int batch) 
		ac->limit = limit;

		ac->batchcount = batch;

		ac->touched = 0;

		spin_lock_init(&ac->lock);

	}

}
@@ -1010,6 +1008,7 @@ static struct alien_cache *__alloc_alien_cache(int node, int entries, 


	alc = kmalloc_node(memsize, gfp, node);

	init_arraycache(&alc->ac, entries, batch);

	spin_lock_init(&alc->lock);

	return alc;

}
@@ -1086,9 +1085,9 @@ static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n) 


		if (alc) {

			ac = &alc->ac;

			if (ac->avail && spin_trylock_irq(&ac->lock)) {

			if (ac->avail && spin_trylock_irq(&alc->lock)) {

				__drain_alien_cache(cachep, ac, node);

				spin_unlock_irq(&ac->lock);

				spin_unlock_irq(&alc->lock);

			}

		}

	}
@@ -1106,9 +1105,9 @@ static void drain_alien_cache(struct kmem_cache *cachep, 
		alc = alien[i];

		if (alc) {

			ac = &alc->ac;

			spin_lock_irqsave(&ac->lock, flags);

			spin_lock_irqsave(&alc->lock, flags);

			__drain_alien_cache(cachep, ac, i);

			spin_unlock_irqrestore(&ac->lock, flags);

			spin_unlock_irqrestore(&alc->lock, flags);

		}

	}

}
@@ -1136,13 +1135,13 @@ static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) 
	if (n->alien && n->alien[nodeid]) {

		alien = n->alien[nodeid];

		ac = &alien->ac;

		spin_lock(&ac->lock);

		spin_lock(&alien->lock);

		if (unlikely(ac->avail == ac->limit)) {

			STATS_INC_ACOVERFLOW(cachep);

			__drain_alien_cache(cachep, ac, nodeid);

		}

		ac_put_obj(cachep, ac, objp);

		spin_unlock(&ac->lock);

		spin_unlock(&alien->lock);

	} else {

		n = get_node(cachep, nodeid);

		spin_lock(&n->list_lock);
@@ -1613,10 +1612,6 @@ void __init kmem_cache_init(void) 


		memcpy(ptr, cpu_cache_get(kmem_cache),

		       sizeof(struct arraycache_init));

		/*

		 * Do not assume that spinlocks can be initialized via memcpy:

		 */

		spin_lock_init(&ptr->lock);



		kmem_cache->array[smp_processor_id()] = ptr;
@@ -1626,10 +1621,6 @@ void __init kmem_cache_init(void) 
		       != &initarray_generic.cache);

		memcpy(ptr, cpu_cache_get(kmalloc_caches[INDEX_AC]),

		       sizeof(struct arraycache_init));

		/*

		 * Do not assume that spinlocks can be initialized via memcpy:

		 */

		spin_lock_init(&ptr->lock);



		kmalloc_caches[INDEX_AC]->array[smp_processor_id()] = ptr;

	}