From: Jens Axboe <axboe@kernel.dk>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Liu Bo <bo.liu@linux.alibaba.com>, stable@vger.kernel.org
Subject: Re: [PATCH] blk-throttle: fix zero wait time for iops throttled group
Date: Wed, 10 Jul 2019 08:25:38 -0600 [thread overview]
Message-ID: <5087ebc3-96e9-44a4-a914-eb99f3c33054@kernel.dk> (raw)
In-Reply-To: <f4be51ff-e426-cc44-db94-3c26e2cfbca9@yandex-team.ru>
On 7/10/19 8:24 AM, Konstantin Khlebnikov wrote:
> On 10.07.2019 17:00, Jens Axboe wrote:
>> On 7/8/19 9:29 AM, Konstantin Khlebnikov wrote:
>>> After commit 991f61fe7e1d ("Blk-throttle: reduce tail io latency when iops
>>> limit is enforced") wait time could be zero even if group is throttled and
>>> cannot issue requests right now. As a result throtl_select_dispatch() turns
>>> into busy-loop under irq-safe queue spinlock.
>>>
>>> Fix is simple: always round up target time to the next throttle slice.
>>
>> Applied, thanks. In the future, please break lines at 72 chars in
>> commit messages, I fixed it up.
>>
>
> Ok, but Documentation/process/submitting-patches.rst and
> scripts/checkpatch.pl recommends 75 chars per line.
Huh, oh well. Not a big deal for me, line breaking is easily automated.
--
Jens Axboe
prev parent reply other threads:[~2019-07-10 14:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-08 15:29 Konstantin Khlebnikov
2019-07-08 19:08 ` Liu Bo
2019-07-09 7:18 ` Konstantin Khlebnikov
2019-07-10 10:42 ` Konstantin Khlebnikov
2019-07-10 14:00 ` Jens Axboe
2019-07-10 14:24 ` Konstantin Khlebnikov
2019-07-10 14:25 ` Jens Axboe [this message]
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