diff options
| author | Andrew Morton <akpm@osdl.org> | 2004-06-23 18:54:49 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-06-23 18:54:49 -0700 |
| commit | b167eef8224b01dec3f15bb95936595013a6066f (patch) | |
| tree | 1ca24fa09e56c2891513f3fe246d7590acb1864f /mm | |
| parent | c75b81a5da09be94099cf7b46bdb32fedc8ce71a (diff) | |
| download | history-b167eef8224b01dec3f15bb95936595013a6066f.tar.gz | |
[PATCH] hwcache align kmalloc caches
From: Manfred Spraul <manfred@colorfullife.com>
Reversing the patches that made all caches hw cacheline aligned had an
unintended side effect on the kmalloc caches: Before they had the
SLAB_HWCACHE_ALIGN flag set, now it's clear. This breaks one sgi driver -
it expects aligned caches. Additionally I think it's the right thing to
do: It costs virtually nothing (the caches are power-of-two sized) and
could reduce false sharing.
Additionally, the patch adds back the documentation for the
SLAB_HWCACHE_ALIGN flag.
Signed-Off: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/slab.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/mm/slab.c b/mm/slab.c index 45c5c0549230d0..d99f1eb10dbf2f 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -129,6 +129,10 @@ #define ARCH_KMALLOC_MINALIGN 0 #endif +#ifndef ARCH_KMALLOC_FLAGS +#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN +#endif + /* Legal flag mask for kmem_cache_create(). */ #if DEBUG # define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \ @@ -758,7 +762,7 @@ void __init kmem_cache_init(void) * allow tighter packing of the smaller caches. */ sizes->cs_cachep = kmem_cache_create(names->name, sizes->cs_size, ARCH_KMALLOC_MINALIGN, - SLAB_PANIC, NULL, NULL); + (ARCH_KMALLOC_FLAGS | SLAB_PANIC), NULL, NULL); /* Inc off-slab bufctl limit until the ceiling is hit. */ if (!(OFF_SLAB(sizes->cs_cachep))) { @@ -768,7 +772,8 @@ void __init kmem_cache_init(void) sizes->cs_dmacachep = kmem_cache_create(names->name_dma, sizes->cs_size, ARCH_KMALLOC_MINALIGN, - (SLAB_CACHE_DMA | SLAB_PANIC), NULL, NULL); + (ARCH_KMALLOC_FLAGS | SLAB_CACHE_DMA | SLAB_PANIC), + NULL, NULL); sizes++; names++; @@ -1116,8 +1121,9 @@ static void slab_destroy (kmem_cache_t *cachep, struct slab *slabp) * %SLAB_NO_REAP - Don't automatically reap this cache when we're under * memory pressure. * - * %SLAB_HWCACHE_ALIGN - This flag has no effect and will be removed soon. - * + * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware + * cacheline. This can be beneficial if you're counting cycles as closely + * as davem. */ kmem_cache_t * kmem_cache_create (const char *name, size_t size, size_t align, |