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@xxxxxxxxxx>
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
---
mm/slub.c | 28 +++++++++++++++-------------
1 file changed, 15 insertions(+), 13 deletions(-)
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2012-04-10 10:32:58.634750976 -0500
+++ linux-2.6/mm/slub.c 2012-04-10 10:33:01.818750910 -0500
@@ -1490,12 +1490,12 @@ static inline void remove_partial(struct
}
/*
- * Lock slab, remove from the partial list and put the object into the
- * per cpu freelist.
+ * Remove slab from the partial list, freeze it and
+ * return the pointer to the freelist.
*
* 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,
struct kmem_cache_node *n, struct page *page,
@@ -1510,22 +1510,24 @@ static inline void *acquire_slab(struct
* The old freelist is the list of objects for the
* per cpu allocation list.
*/
- do {
- freelist = page->freelist;
- counters = page->counters;
- new.counters = counters;
- if (mode)
- new.inuse = page->objects;
+ freelist = page->freelist;
+ counters = page->counters;
+ new.counters = counters;
+ if (mode)
+ new.inuse = page->objects;
- VM_BUG_ON(new.frozen);
- new.frozen = 1;
+ VM_BUG_ON(new.frozen);
+ new.frozen = 1;
- } while (!__cmpxchg_double_slab(s, page,
+ if (!__cmpxchg_double_slab(s, page,
freelist, counters,
NULL, new.counters,
- "lock and freeze"));
+ "acquire_slab"))
+
+ return NULL;
remove_partial(n, page);
+ WARN_ON(!freelist);
return freelist;
}
--
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