Re: [PATCH] PM / Hibernate: Fix memory corruption related to swap

[Hugh Dickins]

On Thu, 2 Dec 2010, Andrew Morton wrote:
> On Fri, 3 Dec 2010 00:40:36 +0100
> "Rafael J. Wysocki" <rjw@xxxxxxx> wrote:
> > 
> > This patch is a fix for a regression and nasty memory corruption, so I'd like
> > to push it to Linus for 2.6.37 if there are no objections.

(It will need backport to 2.6.35-stable and 2.6.36-stable:
IIRC it doesn't quite apply cleanly to those, so we'll need
to send a separate version.)

> 
> It looks OK to me for 2.6.37 but for 2.6.38 please let's make
> everything here a 100% no-op for CONFIG_PM_SLEEP=n builds. 
> Specifically the slight overhead in __alloc_pages_nodemask.

I expect you're right that the CONFIG_PM would better be CONFIG__PM_SLEEP;
but I think you misunderstand gfp_allowed_mask in __alloc_pages_nodemask:
it came from slab & slub, to fix some early bootup issues, and predates
Rafael's recent use of it in suspend and hibernation.

> 
> Because given the global nature of saved_gfp_mask and the unlocked way
> in which it is accessed, this facility won't be at all useful for
> anything other than suspend.

... and bootup.

Hugh
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