From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH] fs-writeback: drop wb->list_lock during blk_finish_plug() Date: Fri, 18 Sep 2015 08:23:46 -0600 Message-ID: <55FC1E72.3040500@fb.com> References: <20150917021453.GO3902@dastard> <20150917224230.GF8624@ret.masoncoding.com> <20150917235647.GG8624@ret.masoncoding.com> <20150918003735.GR3902@dastard> <20150918054044.GT3902@dastard> <20150918131615.GI8624@ret.masoncoding.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit To: Chris Mason , Linus Torvalds , Dave Chinner , Jan Kara , Josef Bacik , LKML , linux-fsdevel , Neil Brown , Christoph Hellwig , Tejun Heo Return-path: In-Reply-To: <20150918131615.GI8624@ret.masoncoding.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 09/18/2015 07:16 AM, Chris Mason wrote: > On Thu, Sep 17, 2015 at 11:04:03PM -0700, Linus Torvalds wrote: >> On Thu, Sep 17, 2015 at 10:40 PM, Dave Chinner wrote: >>> >>> Ok, makes sense - the plug is not being flushed as we switch away, >>> but Chris' patch makes it do that. >> >> Yup. > > Huh, that does make much more sense, thanks Linus. I'm wondering where > else I've assumed that cond_resched() unplugged. > >> >> And I actually think Chris' patch is better than the one I sent out >> (but maybe the scheduler people should take a look at the behavior of >> cond_resched()), I just wanted you to test that to verify the >> behavior. It makes no sense for preemption schedule to NOT unplug, the fact that it doesn't is news to me as well. It was never the intent of the unplug-on-schedule to NOT unplug for certain schedule out events, that seems like very odd behavior. -- Jens Axboe