[RFC/PATCH 5/6] memcg: optimize branch

From: KAMEZAWA Hiroyuki
Date: Wed May 14 2008 - 04:07:20 EST


Showing brach direction for obvious conditions.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

---
mm/memcontrol.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

Index: linux-2.6.26-rc2/mm/memcontrol.c
===================================================================
--- linux-2.6.26-rc2.orig/mm/memcontrol.c
+++ linux-2.6.26-rc2/mm/memcontrol.c
@@ -550,7 +550,7 @@ retry:
* The page_cgroup exists and
* the page has already been accounted.
*/
- if (pc) {
+ if (unlikely(pc)) {
VM_BUG_ON(pc->page != page);
VM_BUG_ON(!pc->mem_cgroup);
unlock_page_cgroup(page);
@@ -559,7 +559,7 @@ retry:
unlock_page_cgroup(page);

pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask);
- if (pc == NULL)
+ if (unlikely(pc == NULL))
goto err;

/*
@@ -616,7 +616,7 @@ retry:
pc->flags = PAGE_CGROUP_FLAG_ACTIVE;

lock_page_cgroup(page);
- if (page_get_page_cgroup(page)) {
+ if (unlikely(page_get_page_cgroup(page))) {
unlock_page_cgroup(page);
/*
* Another charge has been added to this page already.
@@ -689,7 +689,7 @@ void __mem_cgroup_uncharge_common(struct
*/
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
- if (!pc)
+ if (unlikely(!pc))
goto unlock;

VM_BUG_ON(pc->page != page);

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