From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id B5E436B004D for ; Sun, 26 Apr 2009 21:15:40 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp ([10.0.50.73]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n3R1FqmA013300 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Mon, 27 Apr 2009 10:15:53 +0900 Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id C9E1845DD7D for ; Mon, 27 Apr 2009 10:15:52 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id ABE6445DD7B for ; Mon, 27 Apr 2009 10:15:52 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 8ECBB1DB803B for ; Mon, 27 Apr 2009 10:15:52 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 402661DB8037 for ; Mon, 27 Apr 2009 10:15:52 +0900 (JST) Date: Mon, 27 Apr 2009 10:14:19 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [BUGFIX][PATCH] memcg: fix try_get_mem_cgroup_from_swapcache() Message-Id: <20090427101419.465467f7.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090427095100.29173bc1.nishimura@mxp.nes.nec.co.jp> References: <20090426231752.36498c90.d-nishimura@mtf.biglobe.ne.jp> <20090427095100.29173bc1.nishimura@mxp.nes.nec.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Daisuke Nishimura Cc: Andrew Morton , linux-mm , Balbir Singh List-ID: On Mon, 27 Apr 2009 09:51:00 +0900 Daisuke Nishimura wrote: > From: Daisuke Nishimura > > memcg: fix try_get_mem_cgroup_from_swapcache() > > This is a bugfix for commit 3c776e64660028236313f0e54f3a9945764422df(included 2.6.30-rc1). > Used bit of swapcache is solid under page lock, but considering move_account, > pc->mem_cgroup is not. > > We need lock_page_cgroup() anyway. > > Signed-off-by: Daisuke Nishimura you are right. Acked-by: KAMEZAWA Hiroyuki > --- > mm/memcontrol.c | 5 ++--- > 1 files changed, 2 insertions(+), 3 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index ccc69b4..84f856c 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1024,9 +1024,7 @@ static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page) > return NULL; > > pc = lookup_page_cgroup(page); > - /* > - * Used bit of swapcache is solid under page lock. > - */ > + lock_page_cgroup(pc); > if (PageCgroupUsed(pc)) { > mem = pc->mem_cgroup; > if (mem && !css_tryget(&mem->css)) > @@ -1040,6 +1038,7 @@ static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page) > mem = NULL; > rcu_read_unlock(); > } > + unlock_page_cgroup(pc); > return mem; > } > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org