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[107.191.0.158]) by smtp.gmail.com with ESMTPSA id d134-v6sm19926iog.84.2018.08.16.12.10.02 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Aug 2018 12:10:03 -0700 (PDT) Subject: Re: [PATCH BUGFIX/IMPROVEMENT 0/4] bfq: two fixes and one improvement related to I/O control To: Paolo Valente Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, broonie@kernel.org, bfq-iosched@googlegroups.com, oleksandr@natalenko.name References: <20180816165118.17402-1-paolo.valente@linaro.org> From: Jens Axboe Message-ID: <5ac17a9b-1c38-0664-15e3-ff75c9671388@kernel.dk> Date: Thu, 16 Aug 2018 13:10:01 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.0 MIME-Version: 1.0 In-Reply-To: <20180816165118.17402-1-paolo.valente@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 8/16/18 10:51 AM, Paolo Valente wrote: > Hi Jens, > > while working a little bit on cgroups I/O control, I found two nasty > bugs in bfq. They break bandwidth control in simple configurations > with one-process groups. These bugs are fixed by the first two patches > in this series. > > These fixes improved I/O control so much, that I could reduce the > write overcharge factor, used by bfq to counter write-induced > issues. This reduction is performed by the third patch. > > The fourth patch contains a little code improvement I made in a > function that has to do with I/O control. > > I hope we are still in time for 4.19. Patches look fine to me. You are in fact several weeks late for 4.19, I need to have anything that's going in to 4.19 by -rc6 or -rc7 time (depending on whether we have an -rc8 or not). This is to ensure that it gets plenty of time in linux-next as well. I've queued up patches this time (since they were small), but please send them in in due time next time. -- Jens Axboe