Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933273AbZIDI45 (ORCPT ); Fri, 4 Sep 2009 04:56:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933031AbZIDI4y (ORCPT ); Fri, 4 Sep 2009 04:56:54 -0400 Received: from hera.kernel.org ([140.211.167.34]:36697 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933024AbZIDI4w (ORCPT ); Fri, 4 Sep 2009 04:56:52 -0400 Date: Fri, 4 Sep 2009 08:56:14 GMT From: tip-bot for Peter Zijlstra Cc: linux-kernel@vger.kernel.org, ego@in.ibm.com, hpa@zytor.com, mingo@redhat.com, andreas.herrmann3@amd.com, a.p.zijlstra@chello.nl, balbir@in.ibm.com, tglx@linutronix.de, mingo@elte.hu Reply-To: balbir@in.ibm.com, mingo@redhat.com, hpa@zytor.com, ego@in.ibm.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, andreas.herrmann3@amd.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <20090901083826.342231003@chello.nl> References: <20090901083826.342231003@chello.nl> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/balancing] sched: Try to deal with low capacity Message-ID: Git-Commit-ID: bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 04 Sep 2009 08:56:15 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3001 Lines: 103 Commit-ID: bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1 Gitweb: http://git.kernel.org/tip/bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1 Author: Peter Zijlstra AuthorDate: Tue, 1 Sep 2009 10:34:38 +0200 Committer: Ingo Molnar CommitDate: Fri, 4 Sep 2009 10:09:55 +0200 sched: Try to deal with low capacity When the capacity drops low, we want to migrate load away. Allow the load-balancer to remove all tasks when we hit rock bottom. Signed-off-by: Peter Zijlstra Tested-by: Andreas Herrmann Acked-by: Andreas Herrmann Acked-by: Gautham R Shenoy Cc: Balbir Singh LKML-Reference: <20090901083826.342231003@chello.nl> Signed-off-by: Ingo Molnar --- kernel/sched.c | 33 ++++++++++++++++++++++++++++----- 1 files changed, 28 insertions(+), 5 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index ab532b5..5f5b359 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3908,8 +3908,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd, if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) sgs->group_imb = 1; - sgs->group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; - + sgs->group_capacity = + DIV_ROUND_CLOSEST(group->__cpu_power, SCHED_LOAD_SCALE); } /** @@ -3959,7 +3959,7 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu, * and move all the excess tasks away. */ if (prefer_sibling) - sgs.group_capacity = 1; + sgs.group_capacity = min(sgs.group_capacity, 1UL); if (local_group) { sds->this_load = sgs.avg_load; @@ -4191,6 +4191,26 @@ ret: return NULL; } +static struct sched_group *group_of(int cpu) +{ + struct sched_domain *sd = rcu_dereference(cpu_rq(cpu)->sd); + + if (!sd) + return NULL; + + return sd->groups; +} + +static unsigned long power_of(int cpu) +{ + struct sched_group *group = group_of(cpu); + + if (!group) + return SCHED_LOAD_SCALE; + + return group->__cpu_power; +} + /* * find_busiest_queue - find the busiest runqueue among the cpus in group. */ @@ -4203,15 +4223,18 @@ find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, int i; for_each_cpu(i, sched_group_cpus(group)) { + unsigned long power = power_of(i); + unsigned long capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE); unsigned long wl; if (!cpumask_test_cpu(i, cpus)) continue; rq = cpu_rq(i); - wl = weighted_cpuload(i); + wl = weighted_cpuload(i) * SCHED_LOAD_SCALE; + wl /= power; - if (rq->nr_running == 1 && wl > imbalance) + if (capacity && rq->nr_running == 1 && wl > imbalance) continue; if (wl > max_load) { -- 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/