Re: Faster resuming of suspend technology.

Pavel Machek
2006-03-13T10:06:37Z

On Ne 12-03-06 22:32:28, Andreas Mohr wrote:
> Hi,
>
> [CC'd -ck list]
>
> On Sat, Mar 11, 2006 at 02:04:10AM +0900, Jun OKAJIMA wrote:
> >
> >
> > As you might know, one of the key technology of fast booting is suspending.
> > actually, using suspending does fast booting. And very good point is
> > not only can do booting desktop and daemons, but apps at once.
> > but one big fault --- it is slow for a while after booted because of HDD thrashing.
> > (I mention a term suspend as generic one, not refering only to Nigel Cunningham's one)
> I think that is the case since swsusp AFAIR forces as many pages
> as possible into swap and then appends some non-pageable parts
> before shutting down.
> Thus the system will resume with all processes fully residing
> in swap space and the apps getting back to main memory
> on demand only.

Actually... not any more, see /sys/power/image_size.

> And... well... this sounds to me exactly like a prime task
> for the newish swap prefetch work, no need for any other
> special solutions here, I think.
> We probably want a new flag for swap prefetch to let it know
> that we just resumed from software suspend and thus need
> prefetching to happen *much* faster than under normal
> conditions for a short while, though (most likely by
> enabling prefetching on a *non-idle* system for a minute).

Yep, that would be nice. We are actually able to save up-to half of
pagecache, so situation is not as bad as it used to be.
Pavel
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