Re: [PATCH] mm/mempolicy.c: forbid static or relative flags for local NUMA mode

From: David Rientjes
Date: Mon Sep 19 2016 - 20:57:36 EST

On Sun, 18 Sep 2016, Piotr Kwapulinski wrote:

> The MPOL_F_STATIC_NODES and MPOL_F_RELATIVE_NODES flags are irrelevant
> when setting them for MPOL_LOCAL NUMA memory policy via set_mempolicy.
> Return the "invalid argument" from set_mempolicy whenever
> any of these flags is passed along with MPOL_LOCAL.
> It is consistent with MPOL_PREFERRED passed with empty nodemask.
> It also slightly shortens the execution time in paths where these flags
> are used e.g. when trying to rebind the NUMA nodes for changes in
> cgroups cpuset mems (mpol_rebind_preferred()) or when just printing
> the mempolicy structure (/proc/PID/numa_maps).
> Isolated tests done.
> Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@xxxxxxxxx>

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>

There wasn't an MPOL_LOCAL when I introduced either of these flags, it's
an oversight to allow them to be passed.

Want to try to update set_mempolicy(2) with the procedure outlined in as well?