4.12-stable review patch. If anyone has any objections, please let me know.
------------------ From: Rik van Riel <[email protected]> commit 739294fb03f590401bbd7faa6d31a507e3ffada5 upstream. Several tests in the NAS benchmark seem to run a lot slower with NUMA balancing enabled, than with NUMA balancing disabled. The slower run time corresponds with increased idle time. Overriding the final test of migrate_degrades_locality (but still doing the other NUMA tests first) seems to improve performance of those benchmarks. Reported-by: Jirka Hladky <[email protected]> Signed-off-by: Rik van Riel <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Mel Gorman <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- kernel/sched/fair.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6661,6 +6661,10 @@ static int migrate_degrades_locality(str if (dst_nid == p->numa_preferred_nid) return 0; + /* Leaving a core idle is often worse than degrading locality. */ + if (env->idle != CPU_NOT_IDLE) + return -1; + if (numa_group) { src_faults = group_faults(p, src_nid); dst_faults = group_faults(p, dst_nid);
