Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751560Ab3IJJc4 (ORCPT ); Tue, 10 Sep 2013 05:32:56 -0400 Received: from cantor2.suse.de ([195.135.220.15]:57120 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750986Ab3IJJcz (ORCPT ); Tue, 10 Sep 2013 05:32:55 -0400 From: Mel Gorman To: Peter Zijlstra , Rik van Riel Cc: Srikar Dronamraju , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML , Mel Gorman Subject: [PATCH 20/50] sched: Select a preferred node with the most numa hinting faults Date: Tue, 10 Sep 2013 10:32:00 +0100 Message-Id: <1378805550-29949-21-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1378805550-29949-1-git-send-email-mgorman@suse.de> References: <1378805550-29949-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2520 Lines: 78 This patch selects a preferred node for a task to run on based on the NUMA hinting faults. This information is later used to migrate tasks towards the node during balancing. Signed-off-by: Mel Gorman --- include/linux/sched.h | 1 + kernel/sched/core.c | 1 + kernel/sched/fair.c | 17 +++++++++++++++-- 3 files changed, 17 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index dfba435..d6ec68a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1336,6 +1336,7 @@ struct task_struct { struct callback_head numa_work; unsigned long *numa_faults; + int numa_preferred_nid; #endif /* CONFIG_NUMA_BALANCING */ struct rcu_head rcu; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dbc2de6..0235ab8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1643,6 +1643,7 @@ static void __sched_fork(struct task_struct *p) p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; p->numa_migrate_seq = p->mm ? p->mm->numa_scan_seq - 1 : 0; p->numa_scan_period = sysctl_numa_balancing_scan_delay; + p->numa_preferred_nid = -1; p->numa_work.next = &p->numa_work; p->numa_faults = NULL; #endif /* CONFIG_NUMA_BALANCING */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ebd24c0..8c60822 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -879,7 +879,8 @@ static unsigned int task_scan_max(struct task_struct *p) static void task_numa_placement(struct task_struct *p) { - int seq; + int seq, nid, max_nid = -1; + unsigned long max_faults = 0; if (!p->mm) /* for example, ksmd faulting in a user's mm */ return; @@ -889,7 +890,19 @@ static void task_numa_placement(struct task_struct *p) p->numa_scan_seq = seq; p->numa_scan_period_max = task_scan_max(p); - /* FIXME: Scheduling placement policy hints go here */ + /* Find the node with the highest number of faults */ + for_each_online_node(nid) { + unsigned long faults = p->numa_faults[nid]; + p->numa_faults[nid] >>= 1; + if (faults > max_faults) { + max_faults = faults; + max_nid = nid; + } + } + + /* Update the tasks preferred node if necessary */ + if (max_faults && max_nid != p->numa_preferred_nid) + p->numa_preferred_nid = max_nid; } /* -- 1.8.1.4 -- 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/