From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id EE4016B007E for ; Mon, 27 Apr 2009 02:54:08 -0400 (EDT) Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by e28smtp04.in.ibm.com (8.13.1/8.13.1) with ESMTP id n3R6stAu023681 for ; Mon, 27 Apr 2009 12:24:55 +0530 Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n3R6spnH520394 for ; Mon, 27 Apr 2009 12:24:55 +0530 Received: from d28av01.in.ibm.com (loopback [127.0.0.1]) by d28av01.in.ibm.com (8.13.1/8.13.3) with ESMTP id n3R6spOV017897 for ; Mon, 27 Apr 2009 12:24:51 +0530 Date: Mon, 27 Apr 2009 12:23:58 +0530 From: Balbir Singh Subject: Re: [BUGFIX][PATCH] memcg: fix try_get_mem_cgroup_from_swapcache() Message-ID: <20090427065358.GB4454@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com 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=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090427095100.29173bc1.nishimura@mxp.nes.nec.co.jp> Sender: owner-linux-mm@kvack.org To: Daisuke Nishimura Cc: Andrew Morton , linux-mm , KAMEZAWA Hiroyuki List-ID: * nishimura@mxp.nes.nec.co.jp [2009-04-27 09:51:00]: > 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 I think we need to start documenting the locks the page_cgroup lock nests under. If memcg_tasklist were a spinlock instead of mutex, could we use that instead of page_cgroup lock, since we care only about task migration? -- Balbir -- 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