diff options
| author | Ravikiran G Thirumalai <kiran@scalex86.org> | 2006-01-08 01:01:27 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-08 20:13:38 -0800 |
| commit | 22fc6eccbf4ce4eb6265e6ada7b50a7b9cc57d05 (patch) | |
| tree | 3887dc6f1eeb658d773be037971b98d6f5fb3dd7 /include/linux/cache.h | |
| parent | 6d524aed1f50b2b1d5b4ad5a4e2fe3f38106d0a6 (diff) | |
[PATCH] Change maxaligned_in_smp alignemnt macros to internodealigned_in_smp macros
____cacheline_maxaligned_in_smp is currently used to align critical structures
and avoid false sharing. It uses per-arch L1_CACHE_SHIFT_MAX and people find
L1_CACHE_SHIFT_MAX useless.
However, we have been using ____cacheline_maxaligned_in_smp to align
structures on the internode cacheline size. As per Andi's suggestion,
following patch kills ____cacheline_maxaligned_in_smp and introduces
INTERNODE_CACHE_SHIFT, which defaults to L1_CACHE_SHIFT for all arches.
Arches needing L3/Internode cacheline alignment can define
INTERNODE_CACHE_SHIFT in the arch asm/cache.h. Patch replaces
____cacheline_maxaligned_in_smp with ____cacheline_internodealigned_in_smp
With this patch, L1_CACHE_SHIFT_MAX can be killed
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/cache.h')
| -rw-r--r-- | include/linux/cache.h | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/include/linux/cache.h b/include/linux/cache.h index 0b7ecf3af78..ffe52210fc4 100644 --- a/include/linux/cache.h +++ b/include/linux/cache.h @@ -45,12 +45,21 @@ #endif /* CONFIG_SMP */ #endif -#if !defined(____cacheline_maxaligned_in_smp) +/* + * The maximum alignment needed for some critical structures + * These could be inter-node cacheline sizes/L3 cacheline + * size etc. Define this in asm/cache.h for your arch + */ +#ifndef INTERNODE_CACHE_SHIFT +#define INTERNODE_CACHE_SHIFT L1_CACHE_SHIFT +#endif + +#if !defined(____cacheline_internodealigned_in_smp) #if defined(CONFIG_SMP) -#define ____cacheline_maxaligned_in_smp \ - __attribute__((__aligned__(1 << (L1_CACHE_SHIFT_MAX)))) +#define ____cacheline_internodealigned_in_smp \ + __attribute__((__aligned__(1 << (INTERNODE_CACHE_SHIFT)))) #else -#define ____cacheline_maxaligned_in_smp +#define ____cacheline_internodealigned_in_smp #endif #endif |