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From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Nick Piggin <npiggin@gmail.com>,
	Mel Gorman <mgorman@techsingularity.net>, Jan Kara <jack@suse.cz>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Andi Kleen <ak@linux.intel.com>,
	Lukas Czerner <lczerner@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: wait_on_page_bit_common(TASK_KILLABLE, EXCLUSIVE) can miss wakeup?
Date: Mon, 29 Jun 2020 17:13:41 +0200	[thread overview]
Message-ID: <20200629151340.GC20323@redhat.com> (raw)
In-Reply-To: <CAHk-=whvVWNXPJq1k566zn4SfXAifXtiA7T+7JFweR3rQ0nc9A@mail.gmail.com>

On 06/27, Linus Torvalds wrote:
>
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1150,6 +1150,12 @@ static inline int wait_on_page_bit_common(wait_queue_head_t *q,
>  			io_schedule();
>  
>  		if (behavior == EXCLUSIVE) {
> +			/*
> +			 * Make sure we don't get any exclusive wakeups
> +			 * after this point!
> +			 */
> +			__set_current_state(TASK_RUNNING);
> +			smp_mb__before_atomic();
>  			if (!test_and_set_bit_lock(bit_nr, &page->flags))
>  				break;
>  		} else if (behavior == SHARED) {

FWIW,

Reviewed-by: Oleg Nesterov <oleg@redhat.com>


  parent reply	other threads:[~2020-06-29 19:14 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
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 [this message]
2020-06-24 16:22 ` Linus Torvalds
2020-06-24 16:43   ` Oleg Nesterov

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