From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932478AbaDKRYM (ORCPT ); Fri, 11 Apr 2014 13:24:12 -0400 Received: from shelob.surriel.com ([74.92.59.67]:48401 "EHLO shelob.surriel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754451AbaDKRYK (ORCPT ); Fri, 11 Apr 2014 13:24:10 -0400 X-Greylist: delayed 1400 seconds by postgrey-1.27 at vger.kernel.org; Fri, 11 Apr 2014 13:24:10 EDT From: riel@redhat.com To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, peterz@infradead.org, chegu_vinod@hp.com, mgorman@suse.de Subject: [PATCH 2/3] sched,numa: retry placement more frequently when misplaced Date: Fri, 11 Apr 2014 13:00:28 -0400 Message-Id: <1397235629-16328-3-git-send-email-riel@redhat.com> X-Mailer: git-send-email 1.8.5.3 In-Reply-To: <1397235629-16328-1-git-send-email-riel@redhat.com> References: <1397235629-16328-1-git-send-email-riel@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rik van Riel When tasks have not converged on their preferred nodes yet, we want to retry fairly often, to make sure we do not migrate a task's memory to an undesirable location, only to have to move it again later. This patch reduces the interval at which migration is retried, when the task's numa_scan_period is small. Signed-off-by: Rik van Riel Tested-by: Vinod Chegu --- kernel/sched/fair.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 12de50a..babd316 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1326,12 +1326,15 @@ static int task_numa_migrate(struct task_struct *p) /* Attempt to migrate a task to a CPU on the preferred node. */ static void numa_migrate_preferred(struct task_struct *p) { + unsigned long interval = HZ; + /* This task has no NUMA fault statistics yet */ if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults_memory)) return; /* Periodically retry migrating the task to the preferred node */ - p->numa_migrate_retry = jiffies + HZ; + interval = min(interval, msecs_to_jiffies(p->numa_scan_period) / 16); + p->numa_migrate_retry = jiffies + interval; /* Success if task is already running on preferred CPU */ if (task_node(p) == p->numa_preferred_nid) -- 1.8.5.3