From 832a15d209cd260180407bde1af18965b21623f3 Mon Sep 17 00:00:00 2001 From: Joonsoo Kim Date: Tue, 15 Mar 2016 14:54:33 -0700 Subject: [PATCH] mm/slab: align cache size first before determination of OFF_SLAB candidate Finding suitable OFF_SLAB candidate is more related to aligned cache size rather than original size. Same reasoning can be applied to the debug pagealloc candidate. So, this patch moves up alignment fixup to proper position. From that point, size is aligned so we can remove some alignment fixups. Signed-off-by: Joonsoo Kim Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Jesper Dangaard Brouer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index b3d91b048f44..d5dffc806f82 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2125,6 +2125,17 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) else size += BYTES_PER_WORD; } +#endif + + size = ALIGN(size, cachep->align); + /* + * We should restrict the number of objects in a slab to implement + * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition. + */ + if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE) + size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align); + +#if DEBUG /* * To activate debug pagealloc, off-slab management is necessary * requirement. In early phase of initialization, small sized slab @@ -2135,8 +2146,8 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) if (debug_pagealloc_enabled() && (flags & SLAB_POISON) && !slab_early_init && size >= kmalloc_size(INDEX_NODE) && size >= 256 && cachep->object_size > cache_line_size() && - ALIGN(size, cachep->align) < PAGE_SIZE) { - cachep->obj_offset += PAGE_SIZE - ALIGN(size, cachep->align); + size < PAGE_SIZE) { + cachep->obj_offset += PAGE_SIZE - size; size = PAGE_SIZE; } #endif @@ -2148,20 +2159,13 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak) */ if (size >= OFF_SLAB_MIN_SIZE && !slab_early_init && - !(flags & SLAB_NOLEAKTRACE)) + !(flags & SLAB_NOLEAKTRACE)) { /* * Size is large, assume best to place the slab management obj * off-slab (should allow better packing of objs). */ flags |= CFLGS_OFF_SLAB; - - size = ALIGN(size, cachep->align); - /* - * We should restrict the number of objects in a slab to implement - * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition. - */ - if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE) - size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align); + } left_over = calculate_slab_order(cachep, size, flags); -- 2.20.1