From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935213AbbI2RcG (ORCPT ); Tue, 29 Sep 2015 13:32:06 -0400 Received: from mail-io0-f177.google.com ([209.85.223.177]:33744 "EHLO mail-io0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933428AbbI2Rbz (ORCPT ); Tue, 29 Sep 2015 13:31:55 -0400 Subject: Re: [PATCH v4 0/7] blk-mq: fix race conditions on cpu hotplug handling To: Akinobu Mita , linux-kernel@vger.kernel.org References: <1443287365-4244-1-git-send-email-akinobu.mita@gmail.com> Cc: Ming Lei , Tejun Heo , Keith Busch , Christoph Hellwig , Wanpeng Li From: Jens Axboe Message-ID: <560ACB08.9020806@kernel.dk> Date: Tue, 29 Sep 2015 11:31:52 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <1443287365-4244-1-git-send-email-akinobu.mita@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/26/2015 11:09 AM, Akinobu Mita wrote: > This patchset addresses several race conditions on cpu hotplug handling > for blk-mq. All problems can be reproducible by the following script. > > while true; do > echo 0 > /sys/devices/system/cpu/cpu1/online > echo 1 > /sys/devices/system/cpu/cpu1/online > done & > > while true; do > modprobe -r null_blk > modprobe null_blk queue_mode=2 irqmode=1 > sleep 0.1 > done > > * Changes from v3 > - Rebased to the latest kernel > - Add Reviewed-by tags I've reviewed the patches, looks good to me. I've skipped 6/7, as I think we should fix that as part of the percpu ref counting, and not handle it specifically in blk-mq. If we can't get that fix before 4.3 wraps up, then we can revisit and put that in as well. Thanks! -- Jens Axboe