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Date: Sat, 18 Oct 2014 16:49:28 +0200
From: Dominik Dingel <dingel@linux.vnet.ibm.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
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Subject: Re: [PATCH 2/4] mm: introduce new VM_NOZEROPAGE flag
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On Fri, 17 Oct 2014 15:04:21 -0700
Dave Hansen <dave.hansen@intel.com> wrote:
 
> Is there ever a time where the VMAs under an mm have mixed VM_NOZEROPAGE
> status?  Reading the patches, it _looks_ like it might be an all or
> nothing thing.

Currently it is an all or nothing thing, but for a future change we might want to just
tag the guest memory instead of the complete user address space.

> Full disclosure: I've got an x86-specific feature I want to steal a flag
> for.  Maybe we should just define another VM_ARCH bit.
> 

So you think of something like:

#if defined(CONFIG_S390)
# define VM_NOZEROPAGE	VM_ARCH_1
#endif

#ifndef VM_NOZEROPAGE
# define VM_NOZEROPAGE	VM_NONE
#endif

right?