Re: [Devel] [PATCH hci-8.1 2/4] dm-ploop: fix a lost wakeup of the ploop_allocator() thread - no-reply

From: no-reply@sashiko.virtuozzo.com
To: andrey.zhadchenko@virtuozzo.com, "Denis V. Lunev" <den@openvz.org>
Cc: devel@openvz.org
Subject: Re: [Devel] [PATCH hci-8.1 2/4] dm-ploop: fix a lost wakeup of the ploop_allocator() thread
Date: Tue, 3 Nov 2026 08:39:45 +0000	[thread overview]
Message-ID: <010701a1a0907bb3-12ba536b-9457-4862-ab09-edc188c54df5-000000@eu-central-1.amazonses.com> (raw)
In-Reply-To: <20261103083642.130885-3-den@openvz.org>

> From: Denis V. Lunev <den@openvz.org>
> 
> ploop_allocator() tests prealloc_size and only then sets itself
> TASK_INTERRUPTIBLE before schedule(). A request that lands between the
> two finds the thread still running, so wake_up_process() does nothing,
> and the thread goes to sleep with the request pending. A pio whose
> cluster is past the end of the top delta then waits in
> ploop_allocate_cluster() until some later request wakes the thread. The
> dispatcher waits for every runner to go idle before it hands out more
> work, so the whole device stalls, and an idle device has no later
> request.
> 
> Set the task state before testing prealloc_size.
> 
> Fixes: cf489cf22cd5 ("dm-ploop: make filespace preallocations async")
> Reported-by: Konstantin Khorenko <khorenko@virtuozzo.com>
> https://virtuozzo.atlassian.net/browse/VSTOR-152984
> Feature: dm-ploop: ploop target driver
> Signed-off-by: Denis V. Lunev <den@openvz.org>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.vzint.dev/#/patchset/20261103083642.130885-1-den@openvz.org?part=2

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