From 5436205738b6f96b685ffdf3488772a1c4b152db Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Wed, 10 Dec 2014 15:42:18 -0800 Subject: [PATCH] mm/slab: reverse iteration on find_mergeable() Unlike SLUB, sometimes, object isn't started at the beginning of the slab in the SLAB. This causes the unalignment problem when after slab merging is supported by commit 12220dea07f1 ("mm/slab: support slab merge"). Alignment mismatch check is introduced ("mm/slab: fix unalignment problem on Malta with EVA due to slab merge") to prevent merge in this case. This causes undesirable result that merging happens between infrequently used kmem_caches if there are kmem_caches with same size and is 256 bytes, are merged into pool_workqueue rather than kmalloc-256, because kmem_caches for kmalloc are at the tail of the list. To prevent this situation, this patch reverses iteration order in find_mergeable() to find frequently used kmem_caches. This change helps to merge kmem_cache to frequently used kmem_caches, such as kmalloc kmem_caches. Signed-off-by: Joonsoo Kim Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/slab_common.c b/mm/slab_common.c index 06aeaf091f21..2a3f5ff410cf 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -240,7 +240,7 @@ struct kmem_cache *find_mergeable(size_t size, size_t align, size = ALIGN(size, align); flags = kmem_cache_flags(size, flags, name, NULL); - list_for_each_entry(s, &slab_caches, list) { + list_for_each_entry_reverse(s, &slab_caches, list) { if (slab_unmergeable(s)) continue; -- 2.20.1