Re: Suggestion for laptop suspension

From: Richard Gooch (rgooch@ras.ucalgary.ca)
Date: Mon Sep 04 2000 - 10:31:19 EST


Richard Stallman writes:
> Filling memory to zero does not help for my laptop. Perhaps it is
> weird.
>
> But this particular obscure model of laptop is not important. The
> thing is to handle most laptops, to make suspending faster for most
> users, and to build it in by default so that it works "out of the box"
> on most machines.

Well, while it would be a good option to have, I'm not sure it's a
good idea to make it the default. If you flush the buffer+page caches,
then later you will need to repopulate them. That will require
*random* disc activity (i.e. head seeks all over the place).
Contrast that to suspend-to-disc which uses a single contiguous
section.

What would be nicer is if when you suspend, you record the cached
block numbers (and then flush+clear the caches), and on resume kick
off a daemon/kernel thread which touches those blocks, bringing them
back into the caches. Rate-limit the daemon so that "urgent"
(i.e. what the user needs *now*) I/O is only marginally affected.

And since that daemon has time to repopulate, it can re-order the I/O
to avoid head seeks.

Such a scheme I would like to be the default.

                                Regards,

                                        Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca
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