Commit 182fea8f authored Oct 26, 2010 by Richard Kennedy Committed by Linus Torvalds Oct 26, 2010

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>

parent ea05c844

include/linux/rmap.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -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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