From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753266Ab3KTRcP (ORCPT ); Wed, 20 Nov 2013 12:32:15 -0500 Received: from merlin.infradead.org ([205.233.59.134]:48365 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752414Ab3KTRcO (ORCPT ); Wed, 20 Nov 2013 12:32:14 -0500 Message-ID: <528CF1F3.7020106@kernel.dk> Date: Wed, 20 Nov 2013 10:31:31 -0700 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Tejun Heo , Hong Zhiguo CC: vgoyal@redhat.com, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Hong Zhiguo Subject: Re: [PATCH] blkcg: have bh disable for 32bit UP system reading 64bit stats References: <1383736484-393-1-git-send-email-zhiguohong@tencent.com> <20131120172413.GN28946@htj.dyndns.org> In-Reply-To: <20131120172413.GN28946@htj.dyndns.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/20/2013 10:24 AM, Tejun Heo wrote: > On Wed, Nov 06, 2013 at 07:14:44PM +0800, Hong Zhiguo wrote: >> From: Hong Zhiguo >> >> Update of blkg_stat and blkg_rwstat may happen in bh context. >> While u64_stats_fetch_retry is only preempt_disable on 32bit >> UP system. This is not enough to avoid preemption by bh and >> may read strange 64 bit value. >> >> Signed-off-by: Hong Zhiguo > > Acked-by: Tejun Heo > > Jens, can you please pick this one up? This probably needs to be > tagged for stable too. Yeah will do, thanks. -- Jens Axboe