2016-10-27 16:31:15

by Piotr Kwapulinski

Subject: [PATCH v3 0/1] mm/mempolicy.c: forbid static or relative flags for local NUMA mode

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
or mbind.
Return the "invalid argument" from set_mempolicy and mbind whenever
any of these flags is passed along with MPOL_LOCAL.
It is consistent with MPOL_PREFERRED passed with empty nodemask.
It 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 <[email protected]>
---
Changes since V2:
Information from Documentation/vm/numa_memory_policy.txt removed.
Please let me know what else I should do to let this patch to be
accepted.
---
mm/mempolicy.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 0b859af..266893e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -276,7 +276,9 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags,
return ERR_PTR(-EINVAL);
}
} else if (mode == MPOL_LOCAL) {
- if (!nodes_empty(*nodes))
+ if (!nodes_empty(*nodes) ||
+ (flags & MPOL_F_STATIC_NODES) ||
+ (flags & MPOL_F_RELATIVE_NODES))
return ERR_PTR(-EINVAL);
mode = MPOL_PREFERRED;
} else if (nodes_empty(*nodes))
--
2.10.0

2016-11-01 00:21:25

by David Rientjes

Subject: Re: [PATCH v3 0/1] mm/mempolicy.c: forbid static or relative flags for local NUMA mode

On Thu, 27 Oct 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
> or mbind.
> Return the "invalid argument" from set_mempolicy and mbind whenever
> any of these flags is passed along with MPOL_LOCAL.
> It is consistent with MPOL_PREFERRED passed with empty nodemask.
> It 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 <[email protected]>

Acked-by: David Rientjes <[email protected]>