From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx189.postini.com [74.125.245.189]) by kanga.kvack.org (Postfix) with SMTP id BD6536B13F3 for ; Tue, 14 Feb 2012 02:22:05 -0500 (EST) Received: by mail-vw0-f41.google.com with SMTP id p1so5286971vbi.14 for ; Mon, 13 Feb 2012 23:22:05 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20120214121314.6216e0aa.kamezawa.hiroyu@jp.fujitsu.com> References: <20120214120414.025625c2.kamezawa.hiroyu@jp.fujitsu.com> <20120214121314.6216e0aa.kamezawa.hiroyu@jp.fujitsu.com> From: Greg Thelen Date: Mon, 13 Feb 2012 23:21:45 -0800 Message-ID: Subject: Re: [PATCH 3/6 v4] memcg: remove PCG_MOVE_LOCK flag from page_cgroup. Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "hannes@cmpxchg.org" , Michal Hocko , "akpm@linux-foundation.org" , Ying Han , Hugh Dickins On Mon, Feb 13, 2012 at 7:13 PM, KAMEZAWA Hiroyuki wrote: > From ffd1b013fe294a80c12e3f30e85386135a6fb284 Mon Sep 17 00:00:00 2001 > From: KAMEZAWA Hiroyuki > Date: Thu, 2 Feb 2012 11:49:59 +0900 > Subject: [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup. > > PCG_MOVE_LOCK is used for bit spinlock to avoid race between overwriting > pc->mem_cgroup and page statistics accounting per memcg. > This lock helps to avoid the race but the race is very rare because movin= g > tasks between cgroup is not a usual job. > So, it seems using 1bit per page is too costly. > > This patch changes this lock as per-memcg spinlock and removes PCG_MOVE_L= OCK. > > If smaller lock is required, we'll be able to add some hashes but > I'd like to start from this. > > Changelog: > =A0- fixed to pass memcg as an argument rather than page_cgroup. > =A0 =A0and renamed from move_lock_page_cgroup() to move_lock_mem_cgroup() > > Signed-off-by: KAMEZAWA Hiroyuki Seems good. Thanks. Acked-by: Greg Thelen -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org