mm: remove alignment padding from anon_vma on (some) 64 bit builds
authorRichard Kennedy <richard@rsk.demon.co.uk>
Tue, 26 Oct 2010 21:21:55 +0000 (14:21 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 26 Oct 2010 23:52:09 +0000 (16:52 -0700)
commit182fea8f48332de085c0ae936605cb72671db9f2
tree6938047591e9077c416b972c176d4d1d716d95a7
parentea05c8444e451f1cfbf78c68733e717ad7b8602b
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