[RFC][PATCH 7/14] memcg: add prefetch to spinlock

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

Address of "mz" can be calculated in easy way.
prefetch it (we do spin_lock.)


Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
 mm/memcontrol.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: mmtom-2.6.27-rc3+/mm/memcontrol.c
===================================================================
--- mmtom-2.6.27-rc3+.orig/mm/memcontrol.c
+++ mmtom-2.6.27-rc3+/mm/memcontrol.c
@@ -707,6 +707,8 @@ static int mem_cgroup_charge_common(stru
 		}
 	}
 
+	mz = mem_cgroup_zoneinfo(mem, page_to_nid(page), page_zonenum(page));
+	prefetchw(mz);
 	pc->mem_cgroup = mem;
 	pc->page = page;
 	pc->flags = 0;
@@ -729,7 +731,6 @@ static int mem_cgroup_charge_common(stru
 
 	page_assign_page_cgroup(page, pc);
 
-	mz = page_cgroup_zoneinfo(pc);
 	spin_lock_irqsave(&mz->lru_lock, flags);
 	__mem_cgroup_add_list(mz, pc);
 	spin_unlock_irqrestore(&mz->lru_lock, flags);

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