From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 9842A6B009D for ; Wed, 10 Mar 2010 23:53:08 -0500 (EST) Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o2B4r6OP024713 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Thu, 11 Mar 2010 13:53:06 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id E9DE545DE4D for ; Thu, 11 Mar 2010 13:53:05 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id B875A45DE50 for ; Thu, 11 Mar 2010 13:53:05 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 94CE81DB8047 for ; Thu, 11 Mar 2010 13:53:05 +0900 (JST) Received: from m108.s.css.fujitsu.com (m108.s.css.fujitsu.com [10.249.87.108]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 44B411DB803A for ; Thu, 11 Mar 2010 13:53:05 +0900 (JST) Date: Thu, 11 Mar 2010 13:49:08 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH mmotm 2.5/4] memcg: disable irq at page cgroup lock (Re: [PATCH -mmotm 3/4] memcg: dirty pages accounting and limiting infrastructure) Message-Id: <20100311134908.48d8b0fc.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20100311133123.ab10183c.nishimura@mxp.nes.nec.co.jp> References: <20100308105641.e2e714f4.kamezawa.hiroyu@jp.fujitsu.com> <20100308111724.3e48aee3.nishimura@mxp.nes.nec.co.jp> <20100308113711.d7a249da.kamezawa.hiroyu@jp.fujitsu.com> <20100308170711.4d8b02f0.nishimura@mxp.nes.nec.co.jp> <20100308173100.b5997fd4.kamezawa.hiroyu@jp.fujitsu.com> <20100309001252.GB13490@linux> <20100309091914.4b5f6661.kamezawa.hiroyu@jp.fujitsu.com> <20100309102928.9f36d2bb.nishimura@mxp.nes.nec.co.jp> <20100309045058.GX3073@balbir.in.ibm.com> <20100310104309.c5f9c9a9.nishimura@mxp.nes.nec.co.jp> <20100310035624.GP3073@balbir.in.ibm.com> <20100311133123.ab10183c.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: balbir@linux.vnet.ibm.com, linux-mm@kvack.org, Andrea Righi , linux-kernel@vger.kernel.org, Trond Myklebust , Suleiman Souhlal , Andrew Morton , containers@lists.linux-foundation.org, Vivek Goyal List-ID: On Thu, 11 Mar 2010 13:31:23 +0900 Daisuke Nishimura wrote: > On Wed, 10 Mar 2010 09:26:24 +0530, Balbir Singh wrote: > > * nishimura@mxp.nes.nec.co.jp [2010-03-10 10:43:09]: > I made a patch(attached) using both local_irq_disable/enable and local_irq_save/restore. > local_irq_save/restore is used only in mem_cgroup_update_file_mapped. > > And I attached a histogram graph of 30 times kernel build in root cgroup for each. > > before_root: no irq operation(original) > after_root: local_irq_disable/enable for all > after2_root: local_irq_save/restore for all > after3_root: mixed version(attached) > > hmm, there seems to be a tendency that before < after < after3 < after2 ? > Should I replace save/restore version to mixed version ? > IMHO, starting from after2_root version is the easist. If there is a chance to call lock/unlock page_cgroup can be called in interrupt context, we _have to_ disable IRQ, anyway. And if we have to do this, I prefer migration_lock rather than this mixture. BTW, how big your system is ? Balbir-san's concern is for bigger machines. But I'm not sure this change is affecte by the size of machines. I'm sorry I have no big machine, now. I'll consider yet another fix for race in account migration if I can. Thanks, -Kame -- 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