From: Oleg Nesterov <oleg@tv-sign.ru>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: pm list <linux-pm@lists.linux-foundation.org>,
Nigel Cunningham <nigel@nigel.suspend2.net>,
Pavel Machek <pavel@ucw.cz>
Subject: Re: [RFC][PATCH -mm 2/2] Freezer: Use wait queue instead of busy looping
Date: Wed, 25 Jul 2007 17:29:17 +0400 [thread overview]
Message-ID: <20070725132917.GA242@tv-sign.ru> (raw)
In-Reply-To: <200707251409.40592.rjw@sisk.pl>
On 07/25, Rafael J. Wysocki wrote:
>
> void refrigerator(void)
> {
> @@ -50,6 +73,9 @@ void refrigerator(void)
> processes around? */
> long save;
>
> + refrigerator_called = 1;
> + wake_up(&refrigerator_waitq);
> +
This is a bit racy. Unless I missed something, the task should not set
refrigerator_called == 1 until it has PF_FROZEN.
Otherwise, try_to_freeze_tasks() can set refrigerator_called == 0 after
refrigerator() sets it == 1, the the main loop notices this unfrozen task,
and goes to sleep.
(I must admit, I agree with Pavel on that patch).
Oleg.
next prev parent reply other threads:[~2007-07-25 13:29 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-25 12:01 [RFC][PATCH -mm 0/2] Freezer: Use wait queue instead of busy looping Rafael J. Wysocki
2007-07-25 12:03 ` [RFC][PATCH -mm 1/2] Freezer: Be more verbose Rafael J. Wysocki
2007-07-25 12:27 ` Pavel Machek
2007-07-25 12:09 ` [RFC][PATCH -mm 2/2] Freezer: Use wait queue instead of busy looping Rafael J. Wysocki
2007-07-25 12:28 ` Pavel Machek
2007-07-25 12:55 ` Rafael J. Wysocki
2007-07-25 13:29 ` Oleg Nesterov [this message]
2007-07-25 14:03 ` Rafael J. Wysocki
2007-07-25 14:24 ` Oleg Nesterov
2007-07-26 12:24 ` Rafael J. Wysocki
2007-07-26 12:43 ` Rafael J. Wysocki
2007-07-31 8:01 ` Pavel Machek
2007-07-31 9:39 ` Rafael J. Wysocki
2007-07-31 10:00 ` Pavel Machek
2007-07-31 10:17 ` Rafael J. Wysocki
2007-07-31 10:08 ` Rafael J. Wysocki
2007-07-31 10:02 ` Pavel Machek
2007-07-31 22:25 ` [RFC][PATCH -mm 0/3] Freezer: Use wait queue instead of busy looping (updated) Rafael J. Wysocki
2007-07-31 22:26 ` [RFC][PATCH -mm 1/3] Freezer: Use wait queue instead of busy looping Rafael J. Wysocki
2007-08-01 7:59 ` Pavel Machek
2007-07-31 22:28 ` [RFC][PATCH -mm 2/3] Freezer: Measure the time of freezing tasks Rafael J. Wysocki
2007-08-01 8:28 ` Pavel Machek
2007-07-31 22:29 ` [RFC][PATCH -mm 3/3] Freezer: Replace the timeout Rafael J. Wysocki
2007-08-01 8:31 ` Pavel Machek
2007-08-01 10:43 ` Rafael J. Wysocki
2007-08-05 21:37 ` Pavel Machek
2007-08-05 22:38 ` Rafael J. Wysocki
2007-08-05 22:53 ` Pavel Machek
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