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([2605:e000:100e:8c61:85e7:ddeb:bb07:3741]) by smtp.gmail.com with ESMTPSA id k4sm2339675pgg.88.2020.05.14.08.34.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 14 May 2020 08:34:18 -0700 (PDT) Subject: Re: [PATCH block/for-linus] iocost: don't let vrate run wild while there's no saturation signal To: Tejun Heo Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, newella@fb.com References: <20191015001811.GI18794@devbig004.ftw2.facebook.com> <20200514145114.GG16815@mtj.duckdns.org> From: Jens Axboe Message-ID: Date: Thu, 14 May 2020 09:34:17 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200514145114.GG16815@mtj.duckdns.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 5/14/20 8:51 AM, Tejun Heo wrote: > On Mon, Oct 14, 2019 at 05:18:11PM -0700, Tejun Heo wrote: >> When the QoS targets are met and nothing is being throttled, there's >> no way to tell how saturated the underlying device is - it could be >> almost entirely idle, at the cusp of saturation or anywhere inbetween. >> Given that there's no information, it's best to keep vrate as-is in >> this state. Before 7cd806a9a953 ("iocost: improve nr_lagging >> handling"), this was the case - if the device isn't missing QoS >> targets and nothing is being throttled, busy_level was reset to zero. > ... >> Signed-off-by: Tejun Heo >> Reported-by: Andy Newell >> Fixes: 7cd806a9a953 ("iocost: improve nr_lagging handling") > > Jens, this one fell through the cracks. It still applies with only a small > offset. Can you please apply? Looks like it did, queued up for 5.8 now. -- Jens Axboe