Re: [PATCH V2 1/2] mm/autonuma: Let architecture override how the write bit should be stashed in a protnone pte.

From: Michael Ellerman
Date: Tue Feb 14 2017 - 06:01:49 EST

"Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> writes:

> On Tuesday 14 February 2017 11:19 AM, Michael Ellerman wrote:
>> "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> writes:
>>> Autonuma preserves the write permission across numa fault to avoid taking
>>> a writefault after a numa fault (Commit: b191f9b106ea " mm: numa: preserve PTE
>>> write permissions across a NUMA hinting fault"). Architecture can implement
>>> protnone in different ways and some may choose to implement that by clearing Read/
>>> Write/Exec bit of pte. Setting the write bit on such pte can result in wrong
>>> behaviour. Fix this up by allowing arch to override how to save the write bit
>>> on a protnone pte.
>> This is pretty obviously a nop on arches that don't implement the new
>> hooks, but it'd still be good to get an ack from someone in mm land
>> before I merge it.
> To get it apply cleanly you may need

Ah OK, I missed those.

In that case these two should probably go via Andrew's tree.