Subject: Re: [PATCH] build fix for generic debug pagealloc

From: Ingo Molnar <[email-masked]>
Date: Wed, 8 Apr 2009 15:05:10 +0200

* Rafael J. Wysocki <[email-masked]> wrote:

> On Friday 03 April 2009, Ingo Molnar wrote:
> > 
> > * Andrew Morton <[email-masked]> wrote:
> > 
> > > > +config DEBUG_PAGEALLOC
> > > > +	bool "Debug page memory allocations"
> > > > +	depends on DEBUG_KERNEL && ARCH_SUPPORTS_DEBUG_PAGEALLOC
> > > > +	depends on !HIBERNATION || !PPC && !SPARC
> > > > +	---help---
> > > > +	  Unmap pages from the kernel linear mapping after free_pages().
> > > > +	  This results in a large slowdown, but helps to find certain types
> > > > +	  of memory corruptions.
> > > > +
> > > 
> > > I guess this is why it wasn't discovered in my compile testing.  
> > > It's quite regrettable that `make allmodconfig' didn't enable the 
> > > feature. That's what allmodconfig is for.
> > 
> > Hm, i _do_ remember some hibernation magic fix from Rafael, in the 
> > area of debugalloc. Many months ago.
> > 
> > Rafael, is it supposed to work? If yes, i think we should unblock 
> > it.
> 
> Yes, it is, at least on x86.
> 
> ISTR using DEBUG_PAGEALLOC with hibernation quite some time ago 
> already.

Could you please send a patch to Andrew then to remove the above 
dependency?

	Ingo