Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753143Ab2KSCRY (ORCPT ); Sun, 18 Nov 2012 21:17:24 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:43210 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753044Ab2KSCQJ (ORCPT ); Sun, 18 Nov 2012 21:16:09 -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 23/27] sched: Implement NUMA scanning backoff Date: Mon, 19 Nov 2012 03:14:40 +0100 Message-Id: <1353291284-2998-24-git-send-email-mingo@kernel.org> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1353291284-2998-1-git-send-email-mingo@kernel.org> References: <1353291284-2998-1-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: 2258 Lines: 73 Back off slowly from scanning, up to sysctl_sched_numa_scan_period_max (1.6 seconds). Scan faster again if we were forced to switch to another node. This makes sure that workload in equilibrium don't get scanned as often as workloads that are still converging. Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Cc: Andrea Arcangeli Cc: Rik van Riel Cc: Mel Gorman Cc: Hugh Dickins Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 6 ++++++ kernel/sched/fair.c | 8 +++++++- 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index af0602f..ec3cc74 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6024,6 +6024,12 @@ void sched_setnuma(struct task_struct *p, int node, int shared) if (on_rq) enqueue_task(rq, p, 0); task_rq_unlock(rq, p, &flags); + + /* + * Reset the scanning period. If the task converges + * on this node then we'll back off again: + */ + p->numa_scan_period = sysctl_sched_numa_scan_period_min; } #endif /* CONFIG_NUMA_BALANCING */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8f0e6ba..59fea2e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -865,8 +865,10 @@ static void task_numa_placement(struct task_struct *p) } } - if (max_node != p->numa_max_node) + if (max_node != p->numa_max_node) { sched_setnuma(p, max_node, task_numa_shared(p)); + goto out_backoff; + } p->numa_migrate_seq++; if (sched_feat(NUMA_SETTLE) && @@ -882,7 +884,11 @@ static void task_numa_placement(struct task_struct *p) if (shared != task_numa_shared(p)) { sched_setnuma(p, p->numa_max_node, shared); p->numa_migrate_seq = 0; + goto out_backoff; } + return; +out_backoff: + p->numa_scan_period = min(p->numa_scan_period * 2, sysctl_sched_numa_scan_period_max); } /* -- 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/