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([2600:380:8419:743e:a9a6:f93b:f300:79e6]) by smtp.gmail.com with ESMTPSA id v3sm2123221pfn.18.2019.09.24.04.15.56 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Sep 2019 04:15:58 -0700 (PDT) Subject: Re: [PATCH v2 0/2] Optimise io_uring completion waiting To: Pavel Begunkov , Peter Zijlstra Cc: Ingo Molnar , Ingo Molnar , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190923083549.GA42487@gmail.com> <731b2087-7786-5374-68ff-8cba42f0cd68@kernel.dk> <759b9b48-1de3-1d43-3e39-9c530bfffaa0@kernel.dk> <43244626-9cfd-0c0b-e7a1-878363712ef3@gmail.com> <20190924094942.GN2349@hirez.programming.kicks-ass.net> <6f935fb9-6ebd-1df1-0cd0-69e34a16fa7e@kernel.dk> <29e6e06e-351f-c19d-ed7c-51f30c9ca887@kernel.dk> <08193e07-6f05-a496-492d-06ed8ce3aea1@gmail.com> From: Jens Axboe Message-ID: Date: Tue, 24 Sep 2019 13:15:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <08193e07-6f05-a496-492d-06ed8ce3aea1@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 9/24/19 5:11 AM, Pavel Begunkov wrote: > On 24/09/2019 13:34, Jens Axboe wrote: >> On 9/24/19 4:13 AM, Jens Axboe wrote: >>> On 9/24/19 3:49 AM, Peter Zijlstra wrote: >>>> On Tue, Sep 24, 2019 at 10:36:28AM +0200, Jens Axboe wrote: >>>> >>>>> +struct io_wait_queue { >>>>> + struct wait_queue_entry wq; >>>>> + struct io_ring_ctx *ctx; >>>>> + struct task_struct *task; >>>> >>>> wq.private is where the normal waitqueue stores the task pointer. >>>> >>>> (I'm going to rename that) >>> >>> If you do that, then we can just base the io_uring parts on that. >> >> Just took a quick look at it, and ran into block/kyber-iosched.c that >> actually uses the private pointer for something that isn't a task >> struct... >> > > Let reuse autoremove_wake_function anyway. Changed a bit your patch: Yep that should do it, and saves 8 bytes of stack as well. BTW, did you test my patch, this one or the previous? Just curious if it worked for you. -- Jens Axboe