mm: numa: Limit NUMA scanning to migrate-on-fault VMAs
authorMel Gorman <mgorman@suse.de>
Mon, 7 Oct 2013 10:29:09 +0000 (11:29 +0100)
committerIngo Molnar <mingo@kernel.org>
Wed, 9 Oct 2013 10:40:38 +0000 (12:40 +0200)
commitfc3147245d193bd0f57307859c698fa28a20b0fe
treed1c6339ab156fc1f1419fe62164dfd1947cec14d
parent6fe6b2d6dabf392aceb3ad3a5e859b46a04465c6
mm: numa: Limit NUMA scanning to migrate-on-fault VMAs

There is a 90% regression observed with a large Oracle performance test
on a 4 node system. Profiles indicated that the overhead was due to
contention on sp_lock when looking up shared memory policies. These
policies do not have the appropriate flags to allow them to be
automatically balanced so trapping faults on them is pointless. This
patch skips VMAs that do not have MPOL_F_MOF set.

[riel@redhat.com: Initial patch]

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-and-tested-by: Joe Mario <jmario@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-32-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
include/linux/mempolicy.h
kernel/sched/fair.c
mm/mempolicy.c