[PATCH 32/33] sched: Add hysteresis to p->numa_shared
From: Ingo Molnar <mingo@kernel.org>
Date: 2012-11-22 22:52:35
Also in:
lkml
Subsystem:
scheduler, the rest · Maintainers:
Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
Make p->numa_shared flip/flop less around unstable equilibriums, instead require a significant move in either direction to trigger 'dominantly shared accesses' versus 'dominantly private accesses' NUMA status. Suggested-by: Rik van Riel <redacted> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <redacted> Cc: Andrea Arcangeli <redacted> Cc: Rik van Riel <redacted> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/fair.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8aa4b36..ab4a7130 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c@@ -1111,7 +1111,20 @@ static void task_numa_placement(struct task_struct *p) * we might want to consider a different equation below to reduce * the impact of a little private memory accesses. */ - shared = (total[0] >= total[1] / 2); + shared = p->numa_shared; + + if (shared < 0) { + shared = (total[0] >= total[1]); + } else if (shared == 0) { + /* If it was private before, make it harder to become shared: */ + if (total[0] >= total[1]*2) + shared = 1; + } else if (shared == 1 ) { + /* If it was shared before, make it harder to become private: */ + if (total[0]*2 <= total[1]) + shared = 0; + } + if (shared) p->ideal_cpu = sched_update_ideal_cpu_shared(p); else
--
1.7.11.7
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