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From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block <linux-block@vger.kernel.org>,
	linux-kernel@vger.kernel.org, ulf.hansson@linaro.org,
	linus.walleij@linaro.org, bfq-iosched@googlegroups.com,
	Chris Evich <cevich@redhat.com>,
	Patrick Dung <patdung100@gmail.com>,
	Thorsten Schubert <tschubert@bafh.org>
Subject: Re: [PATCH BUGFIX] block, bfq: deschedule empty bfq_queues not referred by any process
Date: Wed, 13 Nov 2019 15:25:14 +0100	[thread overview]
Message-ID: <65fc0bffbcb2296d121b3d5a79108e76@natalenko.name> (raw)
In-Reply-To: <2FB3736A-693E-44B9-9D1F-39AE0D016644@linaro.org>

On 13.11.2019 14:52, Paolo Valente wrote:
>> I'm not sure if I see things right, but this commit along with v5.3.11 
>> kernel causes almost all boots to hang (for instance, on mounting the 
>> FS). Once the scheduler is changed to something else than BFQ (I set 
>> the I/O scheduler early via udev rule), multiple reboots go just fine.
>> 
> 
> If you switch back to bfq after the boot, can you still reproduce the 
> hang?

I didn't try to switch schedulers, but what I see now is once the system 
is able to boot with BFQ, the I/O can still hang on I/O burst (which for 
me happens to happen during VM reboot).

This may also not hang forever, but just slow down considerably. I've 
noticed this inside a KVM VM, not on a real HW.

>> Is this commit also applicable to 5.3 kernels?
> 
> It is.

OK, thanks for clarification.

-- 
   Oleksandr Natalenko (post-factum)

  reply	other threads:[~2019-11-13 14:25 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-12  7:48 [PATCH BUGFIX] block, bfq: deschedule empty bfq_queues not referred by any process Paolo Valente
2019-11-12 15:23 ` Jens Axboe
2019-11-12 17:49   ` Paolo Valente
2019-11-13 12:57 ` Oleksandr Natalenko
2019-11-13 13:52   ` Paolo Valente
2019-11-13 14:25     ` Oleksandr Natalenko [this message]
2019-11-13 15:01       ` Oleksandr Natalenko
2019-11-13 17:42         ` Paolo Valente
2019-11-13 22:46           ` Jens Axboe
2019-11-14  9:22             ` Paolo Valente
2019-11-14  8:53           ` Oleksandr Natalenko
2019-11-14  9:23             ` Paolo Valente

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