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

From: "Rafael J. Wysocki" <[email-masked]>
Date: Fri, 3 Apr 2009 22:38:53 +0200

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.

Thanks,
Rafael