From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net ([212.227.17.22]:51757 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935308AbeBMOal (ORCPT ); Tue, 13 Feb 2018 09:30:41 -0500 Message-ID: <1518532236.15792.25.camel@gmx.de> Subject: Re: [PATCH BUGFIX V3] block, bfq: add requeue-request hook From: Mike Galbraith To: Paolo Valente Cc: Oleksandr Natalenko , Jens Axboe , stable Date: Tue, 13 Feb 2018 15:30:36 +0100 In-Reply-To: References: <20180207211920.6343-1-paolo.valente@linaro.org> <1518197379.26824.31.camel@gmx.de> <6394471.U0O273vb9H@natalenko.name> <9E24F648-C93A-4CEA-A1B6-B041540CEAAE@linaro.org> <1518434553.13087.7.camel@gmx.de> <805e9d5af9aed3fbc2697fdb0ce51e88@natalenko.name> <1518498175.6944.48.camel@gmx.de> <816E0B1B-B2D9-4604-A8CB-1E32AFBF6C22@linaro.org> <1518504174.6944.71.camel@gmx.de> <1518504640.6944.73.camel@gmx.de> Content-Type: text/plain; charset="ISO-8859-15" Mime-Version: 1.0 Content-Transfer-Encoding: 8BIT Sender: stable-owner@vger.kernel.org List-ID: On Tue, 2018-02-13 at 09:15 +0100, Paolo Valente wrote: > > > No bfq in the trace, so probably yet another problem stemming from the > interaction between bfq and blk-mq. Hung tasks seem to wait > indefinitely for a tag, and the only bfq patch that affects tag > distribution is: > a52a69ea89dc block, bfq: limit tags for writes and async I/O > > So, for the next step (and as you already decided to do), please retry > after adding the above commit to your initial pair: > patches/block-bfq:-fix-occurrences-of-request-finish-method-s-old-name.patch > patches/block-bfq:-add-requeue-request-hook.patch I did it a bit differently, revert that commit in master, and skip it in 4.15.3 with the otherwise full set first, and saw no hangs testing either. �I then added it to the 2 patch series, and was rewarded with... no bloody hang. �So it's not as deterministic as it had appeared to be, there's a phase-of-moon factor. �Oh. Joy. -Mike