On Mon, 24 Aug 2015 17:13:23 +0200 Petr Mladek [off-list ref] wrote:

The commit 1dfb059b9438633b0546 ("thp: reduce khugepaged freezing
latency") fixed khugepaged to do not block a system suspend. But
the result is that it could not get interrupted before the given
timeout because the condition for the wait event is "false".

What are the userspace-visible effects of this bug?

This patch puts back the original approach but it uses
freezable_schedule_timeout_interruptible() instead of
schedule_timeout_interruptible(). It does the right thing.
I am pretty sure that the freezable variant was not used in
the original fix only because it was not available at that time.

The regression has been there for ages. It was not critical. It just
did the allocation throttling a little bit more aggressively.

I found this problem when converting the kthread to kthread worker API
and trying to understand the code.

...

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