Re: [PATCH 09/18] mm: numa: Clear numa hinting information on mprotect

From: Rik van Riel
Date: Mon Dec 09 2013 - 10:58:00 EST


On 12/09/2013 02:09 AM, Mel Gorman wrote:
> On a protection change it is no longer clear if the page should be still
> accessible. This patch clears the NUMA hinting fault bits on a protection
> change.

I had to think about this one, because my first thought was
"wait, aren't NUMA ptes inaccessible already?".

Then I thought about doing things like adding read or write
permission in the mprotect, eg. changing from PROT_NONE to
PROT_READ ... and it became unclear what to do with the NUMA
bit in that case...

This patch clears up some confusing situations :)

> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>

Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>

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