Re: [patch 4/8] x86 PAT: hooks in generic vm code to help archs to track pfnmap regions

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 16 Dec 2008 12:07:56 -0800
"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com> wrote:

>  
> 
> >-----Original Message-----
> >From: Andrew Morton [mailto:akpm@linux-foundation.org] 
> >Sent: Tuesday, December 16, 2008 11:57 AM
> >To: Pallipadi, Venkatesh
> >Cc: mingo@elte.hu; tglx@linutronix.de; hpa@zytor.com; 
> >npiggin@suse.de; hugh@veritas.com; rdreier@cisco.com; 
> >jbarnes@virtuousgeek.org; jeremy@goop.org; 
> >arjan@infradead.org; linux-kernel@vger.kernel.org; Pallipadi, 
> >Venkatesh; Siddha, Suresh B
> >Subject: Re: [patch 4/8] x86 PAT: hooks in generic vm code to 
> >help archs to track pfnmap regions

Your emails are getting mucked up.

> >On Wed, 12 Nov 2008 13:26:51 -0800
> >Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> wrote:
> >
> >> --- tip.orig/mm/memory.c	2008-11-11 10:10:11.000000000 -0800
> >> +++ tip/mm/memory.c	2008-11-11 12:10:18.000000000 -0800
> >> @@ -99,6 +99,28 @@ int randomize_va_space __read_mostly =
> >>  					2;
> >>  #endif
> >>  
> >> +#ifndef track_pfn_vma_new
> >> +int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
> >> +			unsigned long pfn, unsigned long size)
> >> +{
> >> +	return 0;
> >> +}
> >> +#endif
> >> +
> >> +#ifndef track_pfn_vma_copy
> >> +int track_pfn_vma_copy(struct vm_area_struct *vma)
> >> +{
> >> +	return 0;
> >> +}
> >> +#endif
> >> +
> >> +#ifndef untrack_pfn_vma
> >> +void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
> >> +			unsigned long size)
> >> +{
> >> +}
> >> +#endif
> >
> >Using __weak would provide a somewhat neater result here.
> >
> 
> Thought about that. But, then remembered the issues with gcc versions and __weak, as in here
> http://lkml.org/lkml/2008/5/1/368
> 
> and decided to take the safer approach.
> 

Yes, it is a concern.