From: Nigel Cunningham <nigel@nigel.suspend2.net>
Reply-To: nigel@suspend2.net
To: "Huang, Ying" <ying.huang@intel.com>
Subject: Re: [RFC][PATCH 1/2 -mm] kexec based hibernation -v3: kexec jump
Date: Thu, 27 Sep 2007 16:35:10 +1000
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Cc: Joseph Fannin <jfannin@gmail.com>, Pavel Machek <pavel@ucw.cz>,
       "Eric W. Biederman" <ebiederm@xmission.com>, nigel@suspend2.net,
       Andrew Morton <akpm@linux-foundation.org>,
       Jeremy Maitin-Shepard <jbms@cmu.edu>, linux-kernel@vger.kernel.org,
       linux-pm@lists.linux-foundation.org,
       Kexec Mailing List <kexec@lists.infradead.org>
References: <1190266447.21818.17.camel@caritas-dev.intel.com> <20070926203036.GF31759@nineveh.local> <1190874834.21818.300.camel@caritas-dev.intel.com>
In-Reply-To: <1190874834.21818.300.camel@caritas-dev.intel.com>
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Hi.

On Thursday 27 September 2007 16:33:54 Huang, Ying wrote:
> On Wed, 2007-09-26 at 16:30 -0400, Joseph Fannin wrote:
> >     But, in my ignorance, I'm not sure even fixing the ext3 bug will
> > guarantee you consistent metadata so that you can handle a
> > swap/hibernate file.  You can do a sync(), but how do you make that
> > not race against running processes without the freezer, or blkdev
> > snapshots?
> > 
> >     I guess uswsusp and the-patch-previously-known-as-suspend2 handle
> > this somehow, though.
> 
> The image-writing kernel of kexec based hibernation run in a controlled
> way. It is not used by normal user, so only really necessary process
> need to be run. For example, it is possible that there is only one user
> process -- the image-writing process running in image-writing kernel.
> So, no freezer or blkdev snapshot is needed.

You're thinking of the wrong kernel - we were talking about prior to switching 
to the kexec'd kernel while suspending.

Regards,

Nigel
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