From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: nigel@nigel.suspend2.net
Subject: Re: Problem with freezable workqueues
Date: Wed, 28 Feb 2007 11:59:35 +0100
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Cc: Johannes Berg <johannes@sipsolutions.net>, Oleg Nesterov <oleg@tv-sign.ru>,
       Pavel Machek <pavel@ucw.cz>, Gautham R Shenoy <ego@in.ibm.com>,
       LKML <linux-kernel@vger.kernel.org>,
       Srivatsa Vaddagiri <vatsa@in.ibm.com>
References: <200702272251.28844.rjw@sisk.pl> <200702280108.57988.rjw@sisk.pl> <1172625254.8580.37.camel@nigel.suspend2.net>
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On Wednesday, 28 February 2007 02:14, Nigel Cunningham wrote:
> Hi.
> 
> On Wed, 2007-02-28 at 01:08 +0100, Rafael J. Wysocki wrote:
> > On Wednesday, 28 February 2007 01:01, Johannes Berg wrote:
> > > On Wed, 2007-02-28 at 00:57 +0100, Rafael J. Wysocki wrote:
> > > 
> > > > Okay, in that case I'd suggest removing create_freezeable_workqueue() and
> > > > make all workqueues nonfreezable once again for 2.6.21 (as far as I know, only
> > > > the two XFS workqueues are affected).
> > > 
> > > I think Nigel might object but I forgot what specific trouble XFS was
> > > causing him.
> > 
> > We suspected that the XFS' worker threads might commit I/O after
> > freeze_processes() has returned, but that hasn't been supported by evidence,
> > as far as I can recall.
> > 
> > Also, making them freezable was controversial ...
> 
> Controversy is no reason to give in! Nevertheless, I think you're right
> - I believe the XFS guys said they fixed the issue that had caused I/O
> to be submitted post-freeze. Well, we'll see if it appears again, won't
> we?

Sure, we will. :-)

Rafael
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