[RFC][PATCH 5/6] memcg: remove unnecessary memory barrier.

From: KAMEZAWA Hiroyuki
Date: Wed Mar 28 2012 - 07:02:24 EST


Now, Used bit and a pointer to memory cgroup are set at once.
memory barrier for Used bit -> pc->mem_cgroup is not necessary.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
mm/memcontrol.c | 2 --
1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 622fd2e..767bef3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1258,8 +1258,6 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
pc = lookup_page_cgroup(page);
if (!PageCgroupUsed(pc))
return NULL;
- /* Ensure pc's mem_cgroup is visible after reading PCG_USED. */
- smp_rmb();
mz = page_cgroup_zoneinfo(pc_to_mem_cgroup(pc), page);
return &mz->reclaim_stat;
}
--
1.7.4.1


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