From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: nigelc@bur.st
Subject: Re: [PATCH -mm 0/2] Use freezeable workqueues to avoid suspend-related XFS corruptions
Date: Mon, 20 Nov 2006 23:55:49 +0100
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Cc: David Chinner <dgc@sgi.com>, Andrew Morton <akpm@osdl.org>,
       LKML <linux-kernel@vger.kernel.org>, Pavel Machek <pavel@ucw.cz>
References: <200611160912.51226.rjw@sisk.pl> <1164061586.15714.1.camel@nigel.suspend2.net> <1164062390.15714.5.camel@nigel.suspend2.net>
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On Monday, 20 November 2006 23:39, Nigel Cunningham wrote:
> (Sorry to reply again)

(No big deal)

> On Tue, 2006-11-21 at 09:26 +1100, Nigel Cunningham wrote:
> > Hi.
> > 
> > On Mon, 2006-11-20 at 23:18 +0100, Rafael J. Wysocki wrote:
> > > I think I/O can only be submitted from the process context.  Thus if we freeze
> > > all (and I mean _all_) threads that are used by filesystems, including worker
> > > threads, we should effectively prevent fs-related I/O from being submitted
> > > after tasks have been frozen.
> > 
> > I know that will work. It's what I used to do before the switch to bdev
> > freezing. I guess I need to look again at why I made the switch. Perhaps
> > it was just because you guys gave freezing kthreads a bad wrap as too
> > invasive or something. Bdev freezing is certainly fewer lines of code.
> 
> No, it looks like I wrongly believed that XFS was submitting I/O off a
> timer, so that freezing kthreads wasn't enough. In that case, it looks
> like freezing kthreads should be a good solution.

Okay, so let's implement it. :-)

Greetings,
Rafael


-- 
You never change things by fighting the existing reality.
		R. Buckminster Fuller
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