Re: [PATCH] mm-slab: allocate kmem_cache with __GFP_REPEAT

From: Pekka Enberg
Date: Wed Jul 20 2011 - 09:15:17 EST

On Wed, 20 Jul 2011, Konstantin Khlebnikov wrote:
Order of sizeof(struct kmem_cache) can be bigger than PAGE_ALLOC_COSTLY_ORDER,
thus there is a good chance of unsuccessful allocation.
With __GFP_REPEAT buddy-allocator will reclaim/compact memory more aggressively.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
mm/slab.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index d96e223..53bddc8 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2304,7 +2304,7 @@ kmem_cache_create (const char *name, size_t size, size_t align,

/* Get cache's description obj. */
- cachep = kmem_cache_zalloc(&cache_cache, gfp);
+ cachep = kmem_cache_zalloc(&cache_cache, gfp | __GFP_REPEAT);
if (!cachep)
goto oops;

The changelog isn't that convincing, really. This is kmem_cache_create() so I'm surprised we'd ever get NULL here in practice. Does this fix some problem you're seeing? If this is really an issue, I'd blame the page allocator as GFP_KERNEL should just work.

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