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slub: Acquire_slab() avoid loop

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Avoid the loop in acquire slab and simply fail if there is a conflict.

This will cause the next page on the list to be considered.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Christoph Lameter 2012-05-09 10:09:53 -05:00 committed by Pekka Enberg
parent 507effeaba
commit 7ced371971
1 changed files with 15 additions and 13 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

28
mm/slub.c
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@ -1490,12 +1490,12 @@ static inline void remove_partial(struct kmem_cache_node *n,
} }
/* /*
* Lock slab, remove from the partial list and put the object into the * Remove slab from the partial list, freeze it and
* per cpu freelist. * return the pointer to the freelist.
* *
* Returns a list of objects or NULL if it fails. * Returns a list of objects or NULL if it fails.
* *
* Must hold list_lock. * Must hold list_lock since we modify the partial list.
*/ */
static inline void *acquire_slab(struct kmem_cache *s, static inline void *acquire_slab(struct kmem_cache *s,
struct kmem_cache_node *n, struct page *page, struct kmem_cache_node *n, struct page *page,
@ -1510,22 +1510,24 @@ static inline void *acquire_slab(struct kmem_cache *s,
* The old freelist is the list of objects for the * The old freelist is the list of objects for the
* per cpu allocation list. * per cpu allocation list.
*/ */
do { freelist = page->freelist;
freelist = page->freelist; counters = page->counters;
counters = page->counters; new.counters = counters;
new.counters = counters; if (mode)
if (mode) new.inuse = page->objects;
new.inuse = page->objects;
VM_BUG_ON(new.frozen); VM_BUG_ON(new.frozen);
new.frozen = 1; new.frozen = 1;
} while (!__cmpxchg_double_slab(s, page, if (!__cmpxchg_double_slab(s, page,
freelist, counters, freelist, counters,
NULL, new.counters, NULL, new.counters,
"lock and freeze")); "acquire_slab"))
return NULL;
remove_partial(n, page); remove_partial(n, page);
WARN_ON(!freelist);
return freelist; return freelist;
} }