From 182fea8f48332de085c0ae936605cb72671db9f2 Mon Sep 17 00:00:00 2001
From: Richard Kennedy <richard@rsk.demon.co.uk>
Date: Tue, 26 Oct 2010 14:21:55 -0700
Subject: [PATCH] mm: remove alignment padding from anon_vma on (some) 64 bit
builds
Reorder structure anon_vma to remove alignment padding on 64 builds when
(CONFIG_KSM || CONFIG_MIGRATION).
This will shrink the size of the anon_vma structure from 40 to 32 bytes
& allow more objects per slab in its kmem_cache.
Under slub the objects in the anon_vma kmem_cache will then be 40 bytes
with 102 objects per slab. (On v2.6.36 without this patch,the size is 48
bytes and 85 objects/slab.)
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/rmap.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 31b2fd75dcba..5c98df68a953 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -25,8 +25,8 @@
* pointing to this anon_vma once its vma list is empty.
*/
struct anon_vma {
- spinlock_t lock; /* Serialize access to vma list */
struct anon_vma *root; /* Root of this anon_vma tree */
+ spinlock_t lock; /* Serialize access to vma list */
#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
/*
--
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