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Date: Sat, 7 Jul 2007 13:31:18 +0200
From: Pavel Machek <pavel@ucw.cz>
To: nigel@suspend2.net
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
       pm list <linux-pm@lists.linux-foundation.org>,
       Alan Stern <stern@rowland.harvard.edu>,
       LKML <linux-kernel@vger.kernel.org>, Oliver Neukum <oliver@neukum.org>,
       Miklos Szeredi <miklos@szeredi.hu>,
       Benjamin Herrenschmidt <benh@kernel.crashing.org>,
       Matthew Garrett <mjg59@srcf.ucam.org>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [RFC][PATCH -mm] Freezer: Handle uninterruptible tasks
Message-ID: <20070707113118.GA2789@elf.ucw.cz>
References: <200707061012.48998.rjw@sisk.pl> <20070707075018.GB2638@elf.ucw.cz> <200707071913.43482.nigel@nigel.suspend2.net>
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Hi!

> > I don't think we can do that. I suspect rename looks like:
> > 
> > 	write directory entry in source
> > A)	(uninterruptible wait for write)
> > 	write directory entry in destination
> > 	(uninterruptible wait for write)
> > 	write something else
> > 
> > If we freeze some task in place "A)", we'll write to the disk when the
> > directory write is finished :-(.
> 
> Renaming is a single syscall, so won't the process get frozen when the syscall 
> finishes? 

It would be frozen when syscall finishes. But if we freeze it at A)
point, we have a problem.

> Perhaps you've just found more logic for keeping the sys_sync there?

No, I don't think so.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html