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[209.132.180.67]) by mx.google.com with ESMTP id h34si9513540pld.290.2019.05.10.13.19.48; Fri, 10 May 2019 13:20:05 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=bVft6V5x; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728028AbfEJUS6 (ORCPT + 99 others); Fri, 10 May 2019 16:18:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:35408 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727911AbfEJUS5 (ORCPT ); Fri, 10 May 2019 16:18:57 -0400 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F2F2D217F5; Fri, 10 May 2019 20:18:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557519537; bh=Q/hdExccvJjNzjv6Qv8a4/VCle6IDL5htrBTYUcGjr4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bVft6V5xugEbJpoW4Q5HmHOuZ+5Bl20NunFrAETP+6/Gj1j2JnlCiJJ7vq2LrEZ1z 52yK21jmbI8xcqT322Bd7bhDPrdTkPcmcS9YHUWelrbXW2IKH+n7xJOwsS7pOgD9KD KQ+dDTlBXkBPrgEOuUY0ytOTJ28RmK7yiowTK/aw= Date: Fri, 10 May 2019 16:18:55 -0400 From: Sasha Levin To: Eric Wheeler Cc: Paolo Valente , Jens Axboe , "open list:BFQ I/O SCHEDULER" , open list , Eric Wheeler , stable@vger.kernel.org Subject: Re: [PATCH] bfq: backport: update internal depth state when queue depth changes Message-ID: <20190510201855.GB14410@sasha-vm> References: <1557510992-18506-1-git-send-email-stable@lists.ewheeler.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <1557510992-18506-1-git-send-email-stable@lists.ewheeler.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 10, 2019 at 10:56:32AM -0700, Eric Wheeler wrote: >From: Jens Axboe > >commit 77f1e0a52d26242b6c2dba019f6ebebfb9ff701e upstream > >A previous commit moved the shallow depth and BFQ depth map calculations >to be done at init time, moving it outside of the hotter IO path. This >potentially causes hangs if the users changes the depth of the scheduler >map, by writing to the 'nr_requests' sysfs file for that device. > >Add a blk-mq-sched hook that allows blk-mq to inform the scheduler if >the depth changes, so that the scheduler can update its internal state. > >Signed-off-by: Eric Wheeler >Tested-by: Kai Krakow >Reported-by: Paolo Valente >Fixes: f0635b8a416e ("bfq: calculate shallow depths at init time") >Signed-off-by: Jens Axboe >Cc: stable@vger.kernel.org I wasn't clear on what was backported here, so I've queued the upstream version on 4.19 and 4.14, it doesn't seem to be relevant to older branches. -- Thanks, Sasha