Re: [patch 2] mm: speculative get_page

Pavel Machek
2005-06-29T21:23:26Z

Hi!

> > > > I think there are a a few ways that bits can be reclaimed if we
> > > > start digging. swsusp uses 2 which seems excessive though may be
> > > > fully justified.
> > >
> > > They (swsusp) actually don't need the bits at all until suspend-time, at
> > > all. Somebody coded up a "dynamic page flags" patch that let them kill
> > > the page->flags use, but it didn't really go anywhere. Might be nice if
> > > someone dug it up. I probably have a copy somewhere.
> >
> > Unfortunately that patch was rather ugly :-(.
>
> Do you think the idea was ugly, or just the implementation? Is there
> something that you'd rather see?

Well, implementation was ugly and idea was unneccesary because we
still had bits left.

We could spare bits for swsusp by defining "PageReserved | PageLocked
=> PageNosave" etc.... simply by choosing some otherwise unused
combinations. swsusp is not performance critical...
Pavel
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