Re: [PATCH] [2/16] POISON: Add page flag for poisoned pages

Andrew Morton
2009-04-08T07:03:59Z

On Wed, 8 Apr 2009 08:24:41 +0200 Andi Kleen <andi@firstfloor.org> wrote:

> On Tue, Apr 07, 2009 at 10:14:21PM -0700, Andrew Morton wrote:
> > On Tue, 7 Apr 2009 17:09:58 +0200 (CEST) Andi Kleen <andi@firstfloor.org> wrote:
> >
> > > Poisoned pages need special handling in the VM and shouldn't be touched
> > > again. This requires a new page flag. Define it here.
> >
> > I wish this patchset didn't change/abuse the well-understood meaning of
> > the word "poison".
>
> Sorry, that's the terminology on the hardware side.
>
> If there's much confusion I could rename it HwPoison or somesuch?

I understand that'd be a PITA but I suspect it would be best,
long-term. Having this conflict in core MM is really pretty bad.

> > > The page flags wars seem to be over, so it shouldn't be a problem
> > > to get a new one. I hope.
> >
> > They are? How did it all get addressed?
>
> Allowing 64bit to use more and using [V]SPARSEMAP to limit flags
> use for zones. I think.

Nobody ever seems to be able to work out how many we actually have
left.