mm/mempolicy: cleanup nodemask intersection check for oom

Patch series "mm/mempolicy: some fix and semantics cleanup", v4.

Current memory policy code has some confusing and ambiguous part about
MPOL_LOCAL policy, as it is handled as a faked MPOL_PREFERRED one, and
there are many places having to distinguish them.  Also the nodemask
intersection check needs cleanup to be more explicit for OOM use, and
handle MPOL_INTERLEAVE correctly.  This patchset cleans up these and
unifies the parameter sanity check for mbind() and set_mempolicy().

This patch (of 3):

mempolicy_nodemask_intersects seem to be a general purpose mempolicy
function.  In fact it is partially tailored for the OOM purpose
instead.  The oom proper is the only existing user so rename the
function to make that purpose explicit.

While at it drop the MPOL_INTERLEAVE as those allocations never has a
nodemask defined (see alloc_page_interleave) so this is a dead code and
a confusing one because MPOL_INTERLEAVE is a hint rather than a hard
requirement so it shouldn't be considered during the OOM.

The final code can be reduced to a check for MPOL_BIND which is the
only memory policy that is a hard requirement and thus relevant to a
constrained OOM logic.

[[email protected]: changelog edits]

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Feng Tang <[email protected]>
Suggested-by: Michal Hocko <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Ben Widawsky <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions