Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751685AbZG3O5b (ORCPT ); Thu, 30 Jul 2009 10:57:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751522AbZG3O5a (ORCPT ); Thu, 30 Jul 2009 10:57:30 -0400 Received: from victor.provo.novell.com ([137.65.250.26]:51983 "EHLO victor.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751439AbZG3O52 (ORCPT ); Thu, 30 Jul 2009 10:57:28 -0400 From: Gregory Haskins Subject: [PATCH 1/2] [RESEND] sched: Fully integrate cpus_active_map and root-domain code To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, rostedt@goodmis.org, rusty@rustcorp.com.au, maxk@qualcomm.com, mingo@elte.hu Date: Thu, 30 Jul 2009 10:57:23 -0400 Message-ID: <20090730145723.25226.24493.stgit@dev.haskins.net> In-Reply-To: <20090730145623.25226.29033.stgit@dev.haskins.net> References: <20090730145623.25226.29033.stgit@dev.haskins.net> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4132 Lines: 116 (Applies to 2.6.31-rc4) [ This patch was originaly sent about a year ago, but got dropped presumably by accident. Here is the original thread. http://lkml.org/lkml/2008/7/22/281 At that time, Peter and Max acked it. It has now been forward ported to the new cpumask interface. I will be so bold as to carry their acks forward since the basic logic is the same. However, a new acknowledgement, if they have the time to review, would be ideal. I have tested this patch on a 4-way system using Max's recommended "echo 0|1 > cpu1/online" technique and it appears to work properly ] What: Reflect "active" cpus in the rq->rd->online field, instead of the online_map. Motivation: Things that use the root-domain code (such as cpupri) only care about cpus classified as "active" anyway. By synchronizing the root-domain state with the active map, we allow several optimizations. For instance, we can remove an extra cpumask_and from the scheduler hotpath by utilizing rq->rd->online (since it is now a cached version of cpu_active_map & rq->rd->span). Signed-off-by: Gregory Haskins Acked-by: Peter Zijlstra Acked-by: Max Krasnyansky --- kernel/sched.c | 2 +- kernel/sched_fair.c | 10 +++++++--- kernel/sched_rt.c | 7 ------- 3 files changed, 8 insertions(+), 11 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 1a104e6..38a1526 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7874,7 +7874,7 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd) rq->rd = rd; cpumask_set_cpu(rq->cpu, rd->span); - if (cpumask_test_cpu(rq->cpu, cpu_online_mask)) + if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) set_rq_online(rq); spin_unlock_irqrestore(&rq->lock, flags); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 9ffb2b2..2b9cae6 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1040,17 +1040,21 @@ static void yield_task_fair(struct rq *rq) * search starts with cpus closest then further out as needed, * so we always favor a closer, idle cpu. * Domains may include CPUs that are not usable for migration, - * hence we need to mask them out (cpu_active_mask) + * hence we need to mask them out (rq->rd->online) * * Returns the CPU we should wake onto. */ #if defined(ARCH_HAS_SCHED_WAKE_IDLE) + +#define cpu_rd_active(cpu, rq) cpumask_test_cpu(cpu, rq->rd->online) + static int wake_idle(int cpu, struct task_struct *p) { struct sched_domain *sd; int i; unsigned int chosen_wakeup_cpu; int this_cpu; + struct rq *task_rq = task_rq(p); /* * At POWERSAVINGS_BALANCE_WAKEUP level, if both this_cpu and prev_cpu @@ -1083,10 +1087,10 @@ static int wake_idle(int cpu, struct task_struct *p) for_each_domain(cpu, sd) { if ((sd->flags & SD_WAKE_IDLE) || ((sd->flags & SD_WAKE_IDLE_FAR) - && !task_hot(p, task_rq(p)->clock, sd))) { + && !task_hot(p, task_rq->clock, sd))) { for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) { - if (cpu_active(i) && idle_cpu(i)) { + if (cpu_rd_active(i, task_rq) && idle_cpu(i)) { if (i != task_cpu(p)) { schedstat_inc(p, se.nr_wakeups_idle); diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index a8f89bc..13f728e 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -1173,13 +1173,6 @@ static int find_lowest_rq(struct task_struct *task) return -1; /* No targets found */ /* - * Only consider CPUs that are usable for migration. - * I guess we might want to change cpupri_find() to ignore those - * in the first place. - */ - cpumask_and(lowest_mask, lowest_mask, cpu_active_mask); - - /* * At this point we have built a mask of cpus representing the * lowest priority tasks in the system. Now we want to elect * the best one based on our affinity and topology. -- 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/