Message-ID: <4546EDD4.70904@comcast.net>
Date: Tue, 31 Oct 2006 01:31:48 -0500
From: John Richard Moser <nigelenki@comcast.net>
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To: "Rafael J. Wysocki" <rjw@sisk.pl>
CC: linux-kernel@vger.kernel.org
Subject: Re: Suspend to disk:  do we HAVE to use swap?
References: <4546C637.5080504@comcast.net> <200610310716.40181.rjw@sisk.pl>
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Rafael J. Wysocki wrote:
> On Tuesday, 31 October 2006 04:42, John Richard Moser wrote:
>> Something dumb came into my head, and the question is thus brought up
>> here:  Do we HAVE to use swap for suspend to disk? How about the file
>> system?
> 
> In short, we could use regular files for the suspend in the same way in which we
> use them for swap.  Namely, we could bmap() a file and create a map of it
> (eg. with extents) that would be used for accessing the corresponding disk
> sectors at the block device level.  Then, to be able to read the image the
> resume code would have to be provided with the number of the sector in which
> the suspend image header is located.
> 
> However, we already have code that allows us to use swap files for the suspend
> and turning a regular file into a swap file is as easy as running 'mkswap' and
> 'swapon' on it.

And the kernel can survive being loaded, mounting a file system
readonly, activating swapon on the swap file on the read-only file
system, and then resuming from it?

Also, the file system is consistent after a suspend to disk?

I believe I mentioned something about compressing the image as well...
> 
> Greetings,
> Rafael
> 
> 

- --
    We will enslave their women, eat their children and rape their
    cattle!
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