Re: [RFC][patch 0/2] mm: remove PageReserved

Hi Nick et al.

On Tue, 2005-08-09 at 14:59, Nick Piggin wrote:

Nigel Cunningham wrote:

quoted

Hi.

On Tue, 2005-08-09 at 07:09, Daniel Phillips wrote:

quoted

quoted

It doesn't look like they'll be able to easily free up a page
flag for 2 reasons. First, PageReserved will probably be kept
around for at least one release. Second, swsusp and some arch
code (ioremap) wants to know about struct pages that don't point
to valid RAM - currently they use PageReserved, but we'll probably
just introduce a PageValidRAM or something when PageReserved goes.

Changing the e820 code so it sets PageNosave instead of PageReserved,
along with a couple of modifications in swsusp itself should get rid of
the swsusp dependency.

That would work for swsusp, but there are other users that want to
know if a struct page is valid ram (eg. ioremap), so in that case
swsusp would not be able to mess with the flag.

Um. Mess with which flag? I guess you mean Reserved. I was saying that
imaging Reserved going away, so for the short term I'd be meaning making
the e820 set both Nosave and Reserved for those pages (which is what the
Suspend2 patches do so as to play nicely with swsusp - I don't use
Reserved at all).

I do think swsusp should (and can, quite easily though I may have
missed something) consolidate PG_nosave and PG_nosave_free, however
that's out of the scope of this patch.

I won't comment here. I don't start at swsusp code that much :>

Nigel
-- 
Evolution.
Enumerate the requirements.
Consider the interdependencies.
Calculate the probabilities.

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