From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx131.postini.com [74.125.245.131]) by kanga.kvack.org (Postfix) with SMTP id BFD366B004D for ; Mon, 20 Feb 2012 03:56:19 -0500 (EST) Date: Mon, 20 Feb 2012 09:56:17 +0100 From: Johannes Weiner Subject: Re: [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup Message-ID: <20120220085617.GC1677@cmpxchg.org> References: <20120217182426.86aebfde.kamezawa.hiroyu@jp.fujitsu.com> <20120217182651.c12bfc5e.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120217182651.c12bfc5e.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , Michal Hocko , Hugh Dickins , Greg Thelen , Ying Han On Fri, Feb 17, 2012 at 06:26:51PM +0900, KAMEZAWA Hiroyuki wrote: > >From 62a96c625be0c30fc5828d88685b6873ed254060 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 moving > 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_LOCK. > > If smaller lock is required, we'll be able to add some hashes but > I'd like to start from this. > > Changelog: > - fixed to pass memcg as an argument rather than page_cgroup. > and renamed from move_lock_page_cgroup() to move_lock_mem_cgroup() > > Acked-by: Greg Thelen > Signed-off-by: KAMEZAWA Hiroyuki Acked-by: Johannes Weiner -- 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