From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932292Ab0EMTMJ (ORCPT ); Thu, 13 May 2010 15:12:09 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:40020 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759389Ab0EMTMH (ORCPT ); Thu, 13 May 2010 15:12:07 -0400 Date: Thu, 13 May 2010 12:11:23 -0700 From: Andrew Morton To: miaox@cn.fujitsu.com Cc: David Rientjes , Lee Schermerhorn , Nick Piggin , Paul Menage , Linux-Kernel , Linux-MM Subject: Re: [PATCH -mm] cpuset,mm: fix no node to alloc memory when changing cpuset's mems - fix2 Message-Id: <20100513121123.e105ac97.akpm@linux-foundation.org> In-Reply-To: <4BEB9941.7040609@cn.fujitsu.com> References: <4BEA56D3.6040705@cn.fujitsu.com> <20100512003246.9f0ee03c.akpm@linux-foundation.org> <4BEA6E3D.10503@cn.fujitsu.com> <20100512104817.beeee3b5.akpm@linux-foundation.org> <4BEB9941.7040609@cn.fujitsu.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.9; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 13 May 2010 14:16:33 +0800 Miao Xie wrote: > > > > The code you have at present is fairly similar to sequence locks. I > > wonder if there's some way of (ab)using sequence locks for this. > > seqlocks don't have lockdep support either... > > > > We can't use sequence locks here, because the read-side may read the data > in changing, but it can't put off cleaning the old bits. I don't understand that sentence. Can you expand on it please?