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Subject: Re: [PATCH v2 0/2] Optimise io_uring completion waiting
To:     Jens Axboe <axboe@kernel.dk>, Peter Zijlstra <peterz@infradead.org>
Cc:     Ingo Molnar <mingo@kernel.org>, Ingo Molnar <mingo@redhat.com>,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
References: <a4996ae7-ac0a-447b-49b2-7e96275aad29@kernel.dk>
 <20190923083549.GA42487@gmail.com>
 <c15b2d54-c722-8fb4-266f-b589c1a21aa5@gmail.com>
 <df612e90-8999-0085-d2d6-4418e044e429@gmail.com>
 <731b2087-7786-5374-68ff-8cba42f0cd68@kernel.dk>
 <759b9b48-1de3-1d43-3e39-9c530bfffaa0@kernel.dk>
 <43244626-9cfd-0c0b-e7a1-878363712ef3@gmail.com>
 <f2608e3d-bb4e-9984-79e8-a2ab4f855c7f@kernel.dk>
 <b999490f-6138-b685-5472-5cd1843b747d@kernel.dk>
 <ed37058b-ee96-7d44-1dc7-d2c48e2ac23f@kernel.dk>
 <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>
 <da86ec56-5f14-536d-2d43-2cc9e118d2a7@kernel.dk>
From:   Pavel Begunkov <asml.silence@gmail.com>
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Message-ID: <6228b13d-5ef6-e83e-b5dc-7a157013d43f@gmail.com>
Date:   Tue, 24 Sep 2019 14:23:03 +0300
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From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>, Ingo Molnar <mingo@redhat.com>,
 linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Message-ID: <6228b13d-5ef6-e83e-b5dc-7a157013d43f@gmail.com>
Subject: Re: [PATCH v2 0/2] Optimise io_uring completion waiting
References: <a4996ae7-ac0a-447b-49b2-7e96275aad29@kernel.dk>
 <20190923083549.GA42487@gmail.com>
 <c15b2d54-c722-8fb4-266f-b589c1a21aa5@gmail.com>
 <df612e90-8999-0085-d2d6-4418e044e429@gmail.com>
 <731b2087-7786-5374-68ff-8cba42f0cd68@kernel.dk>
 <759b9b48-1de3-1d43-3e39-9c530bfffaa0@kernel.dk>
 <43244626-9cfd-0c0b-e7a1-878363712ef3@gmail.com>
 <f2608e3d-bb4e-9984-79e8-a2ab4f855c7f@kernel.dk>
 <b999490f-6138-b685-5472-5cd1843b747d@kernel.dk>
 <ed37058b-ee96-7d44-1dc7-d2c48e2ac23f@kernel.dk>
 <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>
 <da86ec56-5f14-536d-2d43-2cc9e118d2a7@kernel.dk>
In-Reply-To: <da86ec56-5f14-536d-2d43-2cc9e118d2a7@kernel.dk>

--u5CyVYcpD1tHFsT7QXakagEGiOraFbNRl
Content-Type: text/plain; charset=utf-8
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On 24/09/2019 14:15, Jens Axboe wrote:
> 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:
>=20
> Yep that should do it, and saves 8 bytes of stack as well.
>=20
> BTW, did you test my patch, this one or the previous? Just curious if i=
t
> worked for you.
>=20
Not yet, going to do that tonight

--=20
Yours sincerely,
Pavel Begunkov


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