On Wed, 12 Oct 2016, Michael Kerrisk (man-pages) wrote:

quoted

+arguments must specify the empty set. If the "local node" is low
+on free memory the kernel will try to allocate memory from other
+nodes. The kernel will allocate memory from the "local node"
+whenever memory for this node is available. If the "local node"
+is not allowed by the process's current cpuset context the kernel
+will try to allocate memory from other nodes. The kernel will
+allocate memory from the "local node" whenever it becomes allowed
+by the process's current cpuset context. In contrast
+.B MPOL_DEFAULT
+reverts to the policy of the process which may have been set with
+.BR set_mempolicy (2).
+It may not be the "local allocation".

What is the sense of "may not be" here? (And repeated below).
Is the meaning "this could be something other than"?
Presumably the answer is yes, in which case I'll clarify
the wording there. Let me know.

Someone may have set for example a round robin policy with numactl
--interleave before starting the process? Then allocations will go through
all nodes.