From: Jens Axboe <axboe@kernel.dk>
To: Mike Galbraith <efault@gmx.de>, Paolo Valente <paolo.valente@linaro.org>
Cc: Christoph Hellwig <hch@lst.de>,
linux-block <linux-block@vger.kernel.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
LKML <linux-kernel@vger.kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Oleksandr Natalenko <oleksandr@natalenko.name>
Subject: Re: bug in tag handling in blk-mq?
Date: Wed, 9 May 2018 11:01:52 -0600 [thread overview]
Message-ID: <1e51eb57-6d9b-a53c-9cd6-2adfc86b21b5@kernel.dk> (raw)
In-Reply-To: <1525885030.15732.6.camel@gmx.de>
On 5/9/18 10:57 AM, Mike Galbraith wrote:
> On Wed, 2018-05-09 at 09:18 -0600, Jens Axboe wrote:
>> On 5/8/18 10:11 PM, Mike Galbraith wrote:
>>> On Tue, 2018-05-08 at 19:09 -0600, Jens Axboe wrote:
>>>>
>>>> Alright, I managed to reproduce it. What I think is happening is that
>>>> BFQ is limiting the inflight case to something less than the wake
>>>> batch for sbitmap, which can lead to stalls. I don't have time to test
>>>> this tonight, but perhaps you can give it a go when you are back at it.
>>>> If not, I'll try tomorrow morning.
>>>>
>>>> If this is the issue, I can turn it into a real patch. This is just to
>>>> confirm that the issue goes away with the below.
>>>
>>> Confirmed. Impressive high speed bug stomping.
>>
>> Well, that's good news. Can I get you to try this patch?
>
> Sure thing. The original hang (minus provocation patch) being
> annoyingly non-deterministic, this will (hopefully) take a while.
You can verify with the provocation patch as well first, if you wish.
Just need to hand-apply since it'll conflict with this patch in
bfq. But it's a trivial resolve.
--
Jens Axboe
next prev parent reply other threads:[~2018-05-09 17:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-07 14:03 bug in tag handling in blk-mq? Paolo Valente
2018-05-07 14:03 ` Paolo Valente
2018-05-07 16:39 ` Jens Axboe
2018-05-07 18:02 ` Paolo Valente
2018-05-07 18:02 ` Paolo Valente
2018-05-08 4:51 ` Mike Galbraith
2018-05-08 4:51 ` Mike Galbraith
2018-05-08 8:37 ` Mike Galbraith
2018-05-08 8:37 ` Mike Galbraith
2018-05-08 14:55 ` Jens Axboe
2018-05-08 14:55 ` Jens Axboe
2018-05-08 16:42 ` Mike Galbraith
2018-05-08 16:42 ` Mike Galbraith
2018-05-08 20:37 ` Jens Axboe
2018-05-08 21:19 ` Jens Axboe
2018-05-09 1:09 ` Jens Axboe
2018-05-09 4:11 ` Mike Galbraith
2018-05-09 4:11 ` Mike Galbraith
2018-05-09 5:06 ` Paolo Valente
2018-05-09 5:06 ` Paolo Valente
2018-05-09 15:18 ` Jens Axboe
2018-05-09 16:57 ` Mike Galbraith
2018-05-09 16:57 ` Mike Galbraith
2018-05-09 17:01 ` Jens Axboe [this message]
2018-05-09 18:31 ` Mike Galbraith
2018-05-09 18:31 ` Mike Galbraith
2018-05-09 19:50 ` Jens Axboe
2018-05-10 4:38 ` Mike Galbraith
2018-05-10 4:38 ` Mike Galbraith
2018-05-09 5:09 ` Mike Galbraith
2018-05-09 5:09 ` Mike Galbraith
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