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[66.29.188.166]) by smtp.gmail.com with ESMTPSA id g26sm4654481pfh.61.2018.12.07.06.40.47 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 07 Dec 2018 06:40:48 -0800 (PST) Subject: Re: [PATCH BUGFIX 0/2] bfq: fix unbalanced decrements causing loss of throughput To: Paolo Valente Cc: linux-block , linux-kernel , Ulf Hansson , Linus Walleij , Mark Brown , bfq-iosched@googlegroups.com, oleksandr@natalenko.name, federico@willer.it References: <20181206181819.11148-1-paolo.valente@linaro.org> <09393ef1-9559-2042-6c83-75ed3fd529d3@kernel.dk> <8753C347-2BFD-40D4-A97E-DA955BC0207C@linaro.org> From: Jens Axboe Message-ID: <16d4065e-c0d1-7a85-3d9a-242bfd92923e@kernel.dk> Date: Fri, 7 Dec 2018 07:40:45 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <8753C347-2BFD-40D4-A97E-DA955BC0207C@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/7/18 3:01 AM, Paolo Valente wrote: > > >> Il giorno 7 dic 2018, alle ore 03:23, Jens Axboe ha scritto: >> >> On 12/6/18 11:18 AM, Paolo Valente wrote: >>> Hi Jens, >>> the first patch in this series fixes an error in the decrementing of >>> the counter of the number of groups with pending I/O. This wrong >>> decrement caused loss of throughput or, less likely, of control on >>> I/O. The second patch is a fix of some wrong comments, which somehow >>> contributed to making the above bug more difficult to find. >> >> Are you fine with this going into 4.21? I can't quite tell what your >> intent is. The first patch has a Fixes for something > > yep, that fixes a serious error. > >> that went into >> this series, but then patch 2 is a comment update that would not >> normally be something to be applied at this stage. >> > > and yes, only comments changed by the second one > > May it make sense to apply them in two steps, one in the 4.20 and the other one in the 4.21? I think so, I'll do that. -- Jens Axboe