From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
Nick Piggin <npiggin@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Mel Gorman <mgorman@techsingularity.net>, Jan Kara <jack@suse.cz>,
Davidlohr Bueso <dave@stgolabs.net>,
Andi Kleen <ak@linux.intel.com>
Cc: Lukas Czerner <lczerner@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: wait_on_page_bit_common(TASK_KILLABLE, EXCLUSIVE) can miss wakeup?
Date: Wed, 24 Jun 2020 18:20:42 +0200 [thread overview]
Message-ID: <20200624162042.GA12238@redhat.com> (raw)
In-Reply-To: <20200624161142.GA12184@redhat.com>
On 06/24, Oleg Nesterov wrote:
> Suppose that 2 threads T1 and T2 call __lock_page_killable() and sleep in
> wait_on_page_bit_common() -> io_schedule().
>
> T1 is killed, it does test_and_set_bit_lock() but the page is still locked.
>
> unlock_page() calls __wake_up_common(nr_exclusive = 1), this wakes T1 up.
> T2 is not woken.
Ah, please ignore me, sorry for noise.
If T1 is killed it is TASK_RUNNING, try_to_wake_up() should return 0.
Oleg.
next prev parent reply other threads:[~2020-06-24 16:20 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 16:11 wait_on_page_bit_common(TASK_KILLABLE, EXCLUSIVE) can miss wakeup? Oleg Nesterov
2020-06-24 16:20 ` Oleg Nesterov [this message]
2020-06-24 16:36 ` Linus Torvalds
2020-06-26 15:43 ` Peter Zijlstra
2020-06-28 5:39 ` Linus Torvalds
2020-06-28 13:18 ` Peter Zijlstra
2020-06-29 3:28 ` Nicholas Piggin
2020-06-29 13:16 ` Nicholas Piggin
2020-06-29 16:36 ` Linus Torvalds
2020-06-30 2:12 ` Nicholas Piggin
2020-06-29 14:02 ` Oleg Nesterov
2020-06-30 2:08 ` Nicholas Piggin
2020-06-30 6:17 ` Oleg Nesterov
2020-06-30 9:08 ` Nicholas Piggin
2020-06-30 10:53 ` Oleg Nesterov
2020-06-30 11:36 ` Oleg Nesterov
2020-06-30 11:50 ` Oleg Nesterov
2020-06-30 18:02 ` Linus Torvalds
2020-06-30 18:29 ` Oleg Nesterov
2020-06-30 18:57 ` Linus Torvalds
2020-06-29 15:13 ` Oleg Nesterov
2020-06-24 16:22 ` Linus Torvalds
2020-06-24 16:43 ` Oleg Nesterov
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