Re: [PATCH] mm/autonuma: don't use set_pte_at when updating protnone ptes

[Mel Gorman]

On Mon, Feb 06, 2017 at 10:36:16PM +0530, Aneesh Kumar K.V wrote:
> Architectures like ppc64, use privilege access bit to mark pte non accessible.
> This implies that kernel can do a copy_to_user to an address marked for numa fault.
> This also implies that there can be a parallel hardware update for the pte.
> set_pte_at cannot be used in such scenarios. Hence switch the pte
> update to use ptep_get_and_clear and set_pte_at combination.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>

Yeah, ok. The main thing is that it still avoids doing an unnecessary TLB
flush so

Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>

-- 
Mel Gorman
SUSE Labs