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.)
compiled & tested on x86_64 using SLUB
Signed-off-by: Richard Kennedy <richard@xxxxxxxxxxxxxxx>
---
patch against v2.6.36-rc2
compiled & tested on x86_64 AMD X2
regards
Richard
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 31b2fd7..5c98df6 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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