From: Pavel Machek <pavel@ucw.cz>
To: Oliver Neukum <oneukum@suse.de>
Cc: pm list <linux-pm@lists.osdl.org>,
Oliver Neukum <oliver@neukum.name>,
linux-kernel@vger.kernel.org
Subject: Re: question on resume()
Date: Wed, 31 Jan 2007 10:36:53 +0100 [thread overview]
Message-ID: <20070131093653.GA19643@elf.ucw.cz> (raw)
In-Reply-To: <200701311004.19477.oneukum@suse.de>
Hi!
> > Yes, it will. The process freezer can only return success if there are no more
> > TASK_UNINTERRUPTIBLE tasks. Otherwise it fails (after a timeout).
>
> So, this means, on suspend():
>
> 1. Don't worry about TASK_UNINTERRUPTIBLE
> 2. Do worry about TASK_INTERRUPTIBLE
> We have to cease IO and must not call wake_up_interruptible()
"cease IO"? No, I believe it is enough not to start new I/O. Userspace
is frozen at that point, it can't ask you to do I/O.
> Isn't that a race until suspend() is called?
I do not think so.
> On resume():
>
> 1. Don't worry about TASK_UNINTERRUPTIBLE
> 2. Do not restart IO that may call wake_up_interruptible()
>
> When do we restart such IO?
We reuse signal handling code to do that for us. It is same situation
as when someone signals task doing I/O.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
WARNING: multiple messages have this Message-ID (diff)
From: Pavel Machek <pavel@ucw.cz>
To: Oliver Neukum <oneukum@suse.de>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
Alan Stern <stern@rowland.harvard.edu>,
Oliver Neukum <oliver@neukum.name>,
pm list <linux-pm@lists.osdl.org>,
linux-kernel@vger.kernel.org
Subject: Re: [linux-pm] question on resume()
Date: Wed, 31 Jan 2007 10:36:53 +0100 [thread overview]
Message-ID: <20070131093653.GA19643@elf.ucw.cz> (raw)
In-Reply-To: <200701311004.19477.oneukum@suse.de>
Hi!
> > Yes, it will. The process freezer can only return success if there are no more
> > TASK_UNINTERRUPTIBLE tasks. Otherwise it fails (after a timeout).
>
> So, this means, on suspend():
>
> 1. Don't worry about TASK_UNINTERRUPTIBLE
> 2. Do worry about TASK_INTERRUPTIBLE
> We have to cease IO and must not call wake_up_interruptible()
"cease IO"? No, I believe it is enough not to start new I/O. Userspace
is frozen at that point, it can't ask you to do I/O.
> Isn't that a race until suspend() is called?
I do not think so.
> On resume():
>
> 1. Don't worry about TASK_UNINTERRUPTIBLE
> 2. Do not restart IO that may call wake_up_interruptible()
>
> When do we restart such IO?
We reuse signal handling code to do that for us. It is same situation
as when someone signals task doing I/O.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2007-01-31 9:36 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-29 11:06 question on resume() Oliver Neukum
2007-01-29 11:24 ` Nigel Cunningham
2007-01-29 11:34 ` Oliver Neukum
2007-01-29 20:14 ` Nigel Cunningham
2007-01-29 21:04 ` Oliver Neukum
2007-01-29 21:21 ` Nigel Cunningham
2007-01-29 23:10 ` Rafael J. Wysocki
2007-01-30 16:32 ` Rafael J. Wysocki
2007-01-30 16:50 ` Oliver Neukum
2007-01-30 22:32 ` Rafael J. Wysocki
2007-01-30 22:32 ` Rafael J. Wysocki
2007-01-31 8:33 ` Rafael J. Wysocki
2007-01-31 8:33 ` Rafael J. Wysocki
2007-01-31 8:40 ` Oliver Neukum
2007-01-31 8:40 ` Oliver Neukum
2007-01-31 8:49 ` Rafael J. Wysocki
2007-01-31 9:04 ` Oliver Neukum
2007-01-31 9:04 ` Oliver Neukum
2007-01-31 9:36 ` Pavel Machek [this message]
2007-01-31 9:36 ` [linux-pm] " Pavel Machek
2007-01-31 10:14 ` Oliver Neukum
2007-01-31 10:14 ` [linux-pm] " Oliver Neukum
2007-01-31 10:30 ` Pavel Machek
2007-01-31 15:54 ` Alan Stern
2007-01-31 15:54 ` [linux-pm] " Alan Stern
2007-01-31 16:12 ` Oliver Neukum
2007-01-31 16:12 ` [linux-pm] " Oliver Neukum
2007-01-31 16:27 ` Alan Stern
2007-01-31 16:27 ` [linux-pm] " Alan Stern
2007-01-31 18:04 ` Woodruff, Richard
2007-01-31 18:04 ` [linux-pm] " Woodruff, Richard
2007-01-31 15:48 ` Alan Stern
2007-01-31 15:48 ` [linux-pm] " Alan Stern
2007-01-31 18:52 ` Rafael J. Wysocki
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