[PATCH] slab: fix drain_array() so that it works correctly with the shared_array
The list_lock also protects the shared array and we call drain_array() with the shared array. Therefore we cannot go as far as I wanted to but have to take the lock in a way so that it also protects the array_cache in drain_pages. (Note: maybe we should make the array_cache locking more consistent? I.e. always take the array cache lock for shared arrays and disable interrupts for the per cpu arrays?) Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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parent
1b55253a7f
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21
mm/slab.c
21
mm/slab.c
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@ -3521,7 +3521,8 @@ static void enable_cpucache(struct kmem_cache *cachep)
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/*
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* Drain an array if it contains any elements taking the l3 lock only if
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* necessary.
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* necessary. Note that the l3 listlock also protects the array_cache
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* if drain_array() is used on the shared array.
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*/
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void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
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struct array_cache *ac, int force, int node)
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@ -3532,16 +3533,18 @@ void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
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return;
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if (ac->touched && !force) {
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ac->touched = 0;
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} else if (ac->avail) {
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tofree = force ? ac->avail : (ac->limit + 4) / 5;
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if (tofree > ac->avail)
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tofree = (ac->avail + 1) / 2;
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} else {
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spin_lock_irq(&l3->list_lock);
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free_block(cachep, ac->entry, tofree, node);
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if (ac->avail) {
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tofree = force ? ac->avail : (ac->limit + 4) / 5;
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if (tofree > ac->avail)
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tofree = (ac->avail + 1) / 2;
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free_block(cachep, ac->entry, tofree, node);
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ac->avail -= tofree;
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memmove(ac->entry, &(ac->entry[tofree]),
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sizeof(void *) * ac->avail);
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}
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spin_unlock_irq(&l3->list_lock);
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ac->avail -= tofree;
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memmove(ac->entry, &(ac->entry[tofree]),
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sizeof(void *) * ac->avail);
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}
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}
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