[CC += linux-...@vger.kernel.org]

Since this is a kernel-user-space API change, please CC linux-api@. The kernel source file Documentation/SubmitChecklist notes that all Linux kernel patches that change userspace interfaces should be CCed to linux-...@vger.kernel.org, so that the various parties who are interested in API changes are informed. For further information, see https://www.kernel.org/doc/man-pages/linux-api-ml.html

I think man page should document the change? Also I noticed that MPOL_NUMA itself is missing in the man page...

On 09/18/2016 01:29 PM, 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).

Hmm not sure I understand. How does change in mpol_new() affect mpol_rebind_preferred()?


Isolated tests done.

Signed-off-by: Piotr Kwapulinski <kwapulinski.pi...@gmail.com>
 mm/mempolicy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 2da72a5..27b07d1 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))

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