Re: suspend-to-{RAM,disk} for 2.5.17

[Pavel Machek <pavel@suse.cz>]

Hi!

> >> Actually, I just thought of something that might be useful in addition,
> >> which is that it would probably only be necessary to search inside of
> >> page_zone(page), do you agree?
> 
> On Tue, May 28, 2002 at 11:34:08PM +0200, Pavel Machek wrote:
> > Hey, speeding this up is not a top priority. But.. if we can make it
> > simpler as well ... ;-).
> 
> Yeah, system startup/shutdown isn't really something to optimize for
> aside from dodging some worst cases (which is not relevant here).
> 
> 
> On Tue, May 28, 2002 at 11:34:08PM +0200, Pavel Machek wrote:
> > #ifdef CONFIG_SOFTWARE_SUSPEND
> > int is_head_of_free_region(struct page *page)
> > {
> >         zone_t *zone = page_zone(page);
> >         unsigned long flags;
> >         int order;
> >         list_t *curr;
> > 
> >         /*
> >          * Should not matter as we need quiescent system for
> >          * suspend anyway, but...
> >          */
> >         spin_lock_irqsave(&zone->lock, flags);
> >         for (order = MAX_ORDER - 1; order >= 0; --order)
> >                 list_for_each(curr, &zone->free_area[order].free_list){
> >                         if (!curr)
> >                                 break;
> >                         if (page == list_entry(curr, struct page,list)) {
> >                                 spin_unlock_irqrestore(&zone->lock,flags);
> >                                 return 1 << order;
> >                         }
> >                 }
> >         spin_unlock_irqrestore(&zone->lock, flags);
> >         return 0;
> > }
> > #endif /* CONFIG_SOFTWARE_SUSPEND */
> > Does that look okay to you?
> > 							Pavel
> 
> This looks good, though OTOH if we have a page from a zone we should know
> the zone exists, and then maybe the if (!curr) check isn't
> >> needed. If that's

Good point. Killed.

> the case the scary check that almost looks like defensive programming won't
> be needed at all. Also, is it always expected that this will be a
> free page?

No. It may be used page, too. That's why it is asking. 
								Pavel
-- 
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