[RFC][PATCH 0/3] swsusp: Do not use page flags (was: Re: Remove page flags for software suspend)

Rafael J. Wysocki
2007-03-04T13:50:01Z

On Thursday, 1 March 2007 16:33, Rafael J. Wysocki wrote:
> On Thursday, 1 March 2007 16:18, Nick Piggin wrote:
> > Rafael J. Wysocki wrote:
> > > On Wednesday, 28 February 2007 16:25, Christoph Lameter wrote:
> > >
> > >>On Wed, 28 Feb 2007, Pavel Machek wrote:
> > >>
> > >>
> > >>>I... actually do not like that patch. It adds code... at little or no
> > >>>benefit.
> > >>
> > >>We are looking into saving page flags since we are running out. The two
> > >>page flags used by software suspend are rarely needed and should be taken
> > >>out of the flags. If you can do it a different way then please do.
> > >
> > >
> > > As I have already said for a couple of times, I think we can and I'm going to
> > > do it, but right now I'm a bit busy with other things that I consider as more
> > > urgent.
> >
> > I need one bit for lockless pagecache ;)
> >
> > Anyway, I guess if you want something done you have to do it yourself.
> >
> > This patch still needs work (and I don't know if it even works, because
> > I can't make swsusp resume even on a vanilla kernel). But this is my
> > WIP for removing swsusp page flags.
> >
> > This patch adds a simple extent based nosave region tracker, and
> > rearranges some of the snapshot code to be a bit simpler and more
> > amenable to having dynamically allocated flags (they aren't actually
> > dynamically allocated in this patch, however).
>
> Thanks for the patch.
>
> Probably I'd like to do some things in a different way, I'll think about that
> later today.
>
> I hope I'll have a working patch that removes the "offending" page flags after
> the weekend.

Okay, the next three messages contain patches that should do the trick.

They have been tested on x86_64, but not very thoroughly.

Greetings,
Rafael