From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: "Huang, Ying" <ying.huang@intel.com>
Subject: Re: [PATCH 0/2 -mm] kexec based hibernation -v5
Date: Fri, 12 Oct 2007 13:37:17 +0200
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Cc: "Eric W. Biederman" <ebiederm@xmission.com>, Pavel Machek <pavel@ucw.cz>,
       nigel@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: <1192068833.27482.13.camel@caritas-dev.intel.com> <200710111217.58473.rjw@sisk.pl> <1192159172.17539.26.camel@caritas-dev.intel.com>
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On Friday, 12 October 2007 05:19, Huang, Ying wrote:
> On Thu, 2007-10-11 at 12:17 +0200, Rafael J. Wysocki wrote:
> > On Thursday, 11 October 2007 04:13, Huang, Ying wrote:
> > > Kexec base hibernation has some potential advantages over uswsusp and
> > > TuxOnIce (suspend2). Some most obvious advantages are:
> > 
> > Well, I have some doubts as far as the obviousness is concerned.
> 
> OK, I will remove the "obvious".
> 
> > > 1. The hibernation image size can exceed half of memory size easily.
> > 
> > This is also possible with TuxOnIce.
> 
> I will add detail description about this. It is possible with TuxOnIce,
> and hard with u/swsusp.

Actually, possible with TuxOnIce, impossible with u/swsusp, at present.
 
> > > 2. The hibernation image can be written to and read from almost
> > >    anywhere, such as USB disk, NFS.
> > 
> > This is possible with uswsusp, at least in theory, probably with TuxOnIce too.
> 
> I will remove this.

OK, thanks.
 
> > > 3. It is possible to eliminate freezer from kexec based hibernation
> > >    implementation.
> > 
> > This isn't true as long as we have not changed the handling of devices
> > (which is in the works, but will take time).
> 
> I know it has not been implemented yet. I just say that it is possible
> for khibernation and it is almost impossible for u/swsusp and TuxOnIce.

When that's implemented, it may be possible to avoid using the freezer for
u/swsusp and TuxOnIce either.  Time will tell.

Greetings,
Rafael
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