Re: swsusp with highmem, testing wanted

From: Pavel Machek
Date: Thu Mar 25 2004 - 18:04:05 EST


> > I'd need to do atomic copy. (Unless someone can guarantee that during
> > writing to disk, no highmem page is going to be changed...)
> >
> > "copy back" during resume is done in assembly, and I'd rather not
> > dealed with highmem there.
> Can you make that an option ? The PPC version runs in real mode and
> can perfectly copy highmem pages (with small tweaks maybe)

What is real mode on PPC? I do not have PPC here, I guess you'd have
to do that.

> > OTOH, if it possible to guarantee that highmem pages do not change
> > during reads/writes to disk, I might be able to get away without this
> > copy.
> I also think we free too much memory btw (and spend too much time
> trying to free memory). Have you looked at some of Nigel stuffs in
> swsusp2 ? There may be good ideas to borrow...

Yes, swsusp2 is faster. It is also 10x more code. We could probably
stop freeing as soon as half of memory is free; OTOH if memory is
disk cache, it might be faster to drop it than write to swap, then
read back [swsusp2 shows its not usually the case, through].
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
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