Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758890Ab2KVWwf (ORCPT ); Thu, 22 Nov 2012 17:52:35 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:42291 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758859Ab2KVWvy (ORCPT ); Thu, 22 Nov 2012 17:51:54 -0500 From: Ingo Molnar To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Peter Zijlstra , Paul Turner , Lee Schermerhorn , Christoph Lameter , Rik van Riel , Mel Gorman , Andrew Morton , Andrea Arcangeli , Linus Torvalds , Thomas Gleixner , Johannes Weiner , Hugh Dickins Subject: [PATCH 32/33] sched: Add hysteresis to p->numa_shared Date: Thu, 22 Nov 2012 23:49:53 +0100 Message-Id: <1353624594-1118-33-git-send-email-mingo@kernel.org> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1353624594-1118-1-git-send-email-mingo@kernel.org> References: <1353624594-1118-1-git-send-email-mingo@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1779 Lines: 52 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 Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Cc: Andrea Arcangeli Cc: Rik van Riel Cc: Mel Gorman Cc: Hugh Dickins Signed-off-by: Ingo Molnar --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/