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Subject: Re: [PATCH 0/2] Fix misuse of blk_rq_stats in blk-iolatency
From:   Pavel Begunkov <asml.silence@gmail.com>
To:     Josef Bacik <josef@toxicpanda.com>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, dennis@kernel.org
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Message-ID: <ac0700a1-0984-417b-d5d8-35c4ba56f6f6@gmail.com>
Date:   Thu, 11 Jul 2019 04:17:47 +0300
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi,

Any thoughts? Is there something wrong with the patchset?


On 29/06/2019 18:37, Pavel Begunkov wrote:
> Ping?
> 
> On 20/06/2019 10:18, Pavel Begunkov wrote:
>> Hi,
>>
>> Josef, thanks for taking a look.
>>
>>
>> Although, there is nothing critical yet -- just a not working / disabled
>> optimisation, but changes in stats could sublty break it. E.g. grouping
>> @batch and @mean into a union will increase estimated average by several
>> orders of magnitude.
>>
>> Jens, what do you think?
>>
>>
>>
>> On 14/06/2019 16:40, Josef Bacik wrote:
>>> On Fri, Jun 14, 2019 at 02:44:11PM +0300, Pavel Begunkov (Silence) wrote:
>>>> From: Pavel Begunkov <asml.silence@gmail.com>
>>>>
>>>> There are implicit assumptions about struct blk_rq_stats, which make
>>>> it's very easy to misuse. The first patch fixes consequences, and the
>>>> second employs type-system to prevent recurrences.
>>>>
>>>>
>>>> Pavel Begunkov (2):
>>>>   blk-iolatency: Fix zero mean in previous stats
>>>>   blk-stats: Introduce explicit stat staging buffers
>>>>
>>>
>>> I don't have a problem with this, but it's up to Jens I suppose
>>>
>>> Acked-by: Josef Bacik <josef@toxicpanda.com>
>>>
>>> Thanks,
>>>
>>> Josef
>>>
>>
> 

-- 
Yours sincerely,
Pavel Begunkov