Re: [PATCH mmotm] ksm: antidote to MADV_MERGEABLE HWPOISON

[Andi Kleen]

On Fri, Aug 21, 2009 at 07:30:15PM +0100, Hugh Dickins wrote:
> linux-next is now sporting MADV_HWPOISON at 12, which would have a very
> nasty effect on KSM if you had CONFIG_MEMORY_FAILURE=y with CONFIG_KSM=y.
> Shift MADV_MERGEABLE and MADV_UNMERGEABLE down two - two to reduce the
> confusion if old and new userspace and kernel are mismatched.
> 
> Personally I'd prefer the MADV_HWPOISON testing feature to shift; but
> linux-next comes first in the mmotm lineup, and I can't be sure that
> madvise KSM already has more users than there are HWPOISON testers:
> so unless Andi is happy to shift MADV_HWPOISON, mmotm needs this.

Thanks for catching.

Shifting is fine, but I would prefer then if it was to some
value that is not reused (like 100) so that I can probe for it 
in the test programs.

-Andi
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