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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: "linux-mm@kvack.org" <linux-mm@kvack.org>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
	Michal Hocko <mhocko@suse.cz>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Han Ying <yinghan@google.com>,
	Glauber Costa <glommer@parallels.com>,
	Konstantin Khlebnikov <khlebnikov@openvz.org>,
	Suleiman Souhlal <suleiman@google.com>
Subject: [RFC][PATCH 5/6] memcg: remove unnecessary memory barrier.
Date: Wed, 28 Mar 2012 20:00:38 +0900	[thread overview]
Message-ID: <4F72EF56.4030606@jp.fujitsu.com> (raw)
In-Reply-To: <4F72EB84.7080000@jp.fujitsu.com>

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@jp.fujitsu.com>
---
 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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WARNING: multiple messages have this Message-ID (diff)
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: "linux-mm@kvack.org" <linux-mm@kvack.org>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
	Michal Hocko <mhocko@suse.cz>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Han Ying <yinghan@google.com>,
	Glauber Costa <glommer@parallels.com>,
	Konstantin Khlebnikov <khlebnikov@openvz.org>,
	Suleiman Souhlal <suleiman@google.com>
Subject: [RFC][PATCH 5/6] memcg: remove unnecessary memory barrier.
Date: Wed, 28 Mar 2012 20:00:38 +0900	[thread overview]
Message-ID: <4F72EF56.4030606@jp.fujitsu.com> (raw)
In-Reply-To: <4F72EB84.7080000@jp.fujitsu.com>

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@jp.fujitsu.com>
---
 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



  parent reply	other threads:[~2012-03-28 11:02 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-28 10:44 [RFC][PATCH 0/6 v2] reducing page_cgroup size KAMEZAWA Hiroyuki
2012-03-28 10:44 ` KAMEZAWA Hiroyuki
2012-03-28 10:47 ` [RFC][PATCH 1/6] memcg: add methods to access pc->mem_cgroup KAMEZAWA Hiroyuki
2012-03-28 10:47   ` KAMEZAWA Hiroyuki
2012-03-28 10:51 ` [RFC][PATCH 2/6] memcg: add pc_set_mem_cgroup_and_flags() KAMEZAWA Hiroyuki
2012-03-28 10:51   ` KAMEZAWA Hiroyuki
2012-04-17 21:17   ` Ying Han
2012-04-17 21:17     ` Ying Han
2012-04-18  7:23     ` KAMEZAWA Hiroyuki
2012-04-18  7:23       ` KAMEZAWA Hiroyuki
2012-04-18 18:18       ` Ying Han
2012-04-18 18:18         ` Ying Han
2012-03-28 10:57 ` [RFC][PATCH 3/6] memcg: add PageCgroupReset() KAMEZAWA Hiroyuki
2012-03-28 10:57   ` KAMEZAWA Hiroyuki
2012-04-17 21:25   ` Ying Han
2012-04-17 21:25     ` Ying Han
2012-04-18  7:34     ` KAMEZAWA Hiroyuki
2012-04-18  7:34       ` KAMEZAWA Hiroyuki
2012-03-28 10:59 ` [RFC][[PATCH 4/6] memcg: remove mem_cgroup pointer from page_cgroup KAMEZAWA Hiroyuki
2012-03-28 10:59   ` KAMEZAWA Hiroyuki
2012-03-28 11:00 ` KAMEZAWA Hiroyuki [this message]
2012-03-28 11:00   ` [RFC][PATCH 5/6] memcg: remove unnecessary memory barrier KAMEZAWA Hiroyuki
2012-03-28 11:06 ` [RFC][PATCH 6/6] memcg: config for integrate page_cgroup into memmap KAMEZAWA Hiroyuki
2012-03-28 11:06   ` KAMEZAWA Hiroyuki

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