Re: Switch per cpu partial page support off for debugging

From: Pekka Enberg
Date: Mon Dec 12 2011 - 02:16:38 EST


On Wed, 23 Nov 2011, Christoph Lameter wrote:
Eric saw an issue with accounting of slabs during validation. Its not
possible to determine accurately how many per cpu partial slabs exist at
any time so this switches off per cpu partial pages during debug.

Subject: Switch per cpu partial page support off for debugging

Otherwise we have accounting issues.

Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>


---
mm/slub.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2011-11-22 11:57:21.000000000 -0600
+++ linux-2.6/mm/slub.c 2011-11-22 11:57:55.000000000 -0600
@@ -3027,7 +3027,9 @@ static int kmem_cache_open(struct kmem_c
* per node list when we run out of per cpu objects. We only fetch 50%
* to keep some capacity around for frees.
*/
- if (s->size >= PAGE_SIZE)
+ if (kmem_cache_debug(s))
+ s->cpu_partial = 0;
+ else if (s->size >= PAGE_SIZE)
s->cpu_partial = 2;
else if (s->size >= 1024)
s->cpu_partial = 6;

Looks OK to me. CC'ing Eric and David.
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