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

On Tue, 14 Feb 2017 21:59:23 +1100 Michael Ellerman [off-list ref] wrote:

"Aneesh Kumar K.V" [off-list ref] writes:

quoted

On Tuesday 14 February 2017 11:19 AM, Michael Ellerman wrote:

quoted

"Aneesh Kumar K.V" [off-list ref] writes:

quoted

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
http://ozlabs.org/~akpm/mmots/broken-out/mm-autonuma-dont-use-set_pte_at-when-updating-protnone-ptes.patch
http://ozlabs.org/~akpm/mmots/broken-out/mm-autonuma-dont-use-set_pte_at-when-updating-protnone-ptes-fix.patch

Ah OK, I missed those.

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

Done.  But
mm-autonuma-dont-use-set_pte_at-when-updating-protnone-ptes.patch is on
hold because Aneesh saw a testing issue, so these two are also on hold.