From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751276AbdEBOoP (ORCPT ); Tue, 2 May 2017 10:44:15 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:55137 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750723AbdEBOoN (ORCPT ); Tue, 2 May 2017 10:44:13 -0400 Date: Tue, 2 May 2017 16:43:56 +0200 From: Peter Zijlstra To: mingo@kernel.org, lvenanci@redhat.com Cc: lwang@redhat.com, riel@redhat.com, efault@gmx.de, tglx@linutronix.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH 00/14] sched/topology fixes Message-ID: <20170502144356.GB3377@worktop.programming.kicks-ass.net> References: <20170428131958.893188882@infradead.org> <20170428135339.diwcabxhcpu4b5fw@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170428135339.diwcabxhcpu4b5fw@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 28, 2017 at 03:53:39PM +0200, Peter Zijlstra wrote: > Also, the following occurred to me: > > sg_span & sg_mask == sg_mask > > Therefore, we don't need to do the whole "sg_span &" business. > > Hmm? > @@ -856,7 +857,7 @@ build_sched_groups(struct sched_domain * > continue; > > group = get_group(i, sdd, &sg); > - cpumask_setall(sched_group_mask(sg)); > + cpumask_copy(sched_group_mask(sg), sched_group_cpus(sg)); > > for_each_cpu(j, span) { > if (get_group(j, sdd, NULL) != group) OK, so this explodes mightily. That code also hurt my brain bad, so I had to fix that a little. The below seems to boot. --- --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7996,7 +7996,7 @@ static int active_load_balance_cpu_stop( static int should_we_balance(struct lb_env *env) { struct sched_group *sg = env->sd->groups; - struct cpumask *sg_cpus, *sg_mask; + struct cpumask *sg_mask; int cpu, balance_cpu = -1; /* @@ -8006,11 +8006,10 @@ static int should_we_balance(struct lb_e if (env->idle == CPU_NEWLY_IDLE) return 1; - sg_cpus = sched_group_cpus(sg); sg_mask = sched_group_mask(sg); /* Try to find first idle cpu */ - for_each_cpu_and(cpu, sg_cpus, env->cpus) { - if (!cpumask_test_cpu(cpu, sg_mask) || !idle_cpu(cpu)) + for_each_cpu_and(cpu, sg_mask, env->cpus) { + if (!idle_cpu(cpu)) continue; balance_cpu = cpu; --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -85,7 +85,8 @@ static int sched_domain_debug_one(struct group->sgc->id, cpumask_pr_args(sched_group_cpus(group))); - if ((sd->flags & SD_OVERLAP) && !cpumask_full(sched_group_mask(group))) { + if ((sd->flags & SD_OVERLAP) && + !cpumask_equal(sched_group_mask(group), sched_group_cpus(group))) { printk(KERN_CONT " mask=%*pbl", cpumask_pr_args(sched_group_mask(group))); } @@ -505,7 +506,7 @@ enum s_alloc { */ int group_balance_cpu(struct sched_group *sg) { - return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); + return cpumask_first(sched_group_mask(sg)); } @@ -833,23 +834,34 @@ build_overlap_sched_groups(struct sched_ * [*] in other words, the first group of each domain is its child domain. */ -static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) +static struct sched_group *get_group(int cpu, struct sd_data *sdd) { struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); struct sched_domain *child = sd->child; + struct sched_group *sg; if (child) cpu = cpumask_first(sched_domain_span(child)); - if (sg) { - *sg = *per_cpu_ptr(sdd->sg, cpu); - (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu); + sg = *per_cpu_ptr(sdd->sg, cpu); + sg->sgc = *per_cpu_ptr(sdd->sgc, cpu); - /* For claim_allocations: */ - atomic_set(&(*sg)->sgc->ref, 1); + /* For claim_allocations: */ + atomic_inc(&sg->ref); + atomic_inc(&sg->sgc->ref); + + if (child) { + cpumask_copy(sched_group_cpus(sg), sched_domain_span(child)); + cpumask_copy(sched_group_mask(sg), sched_group_cpus(sg)); + } else { + cpumask_set_cpu(cpu, sched_group_cpus(sg)); + cpumask_set_cpu(cpu, sched_group_cpus(sg)); } - return cpu; + sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_cpus(sg)); + sg->sgc->min_capacity = SCHED_CAPACITY_SCALE; + + return sg; } /* @@ -868,34 +880,20 @@ build_sched_groups(struct sched_domain * struct cpumask *covered; int i; - get_group(cpu, sdd, &sd->groups); - atomic_inc(&sd->groups->ref); - - if (cpu != cpumask_first(span)) - return 0; - lockdep_assert_held(&sched_domains_mutex); covered = sched_domains_tmpmask; cpumask_clear(covered); - for_each_cpu(i, span) { + for_each_cpu_wrap(i, span, cpu) { struct sched_group *sg; - int group, j; if (cpumask_test_cpu(i, covered)) continue; - group = get_group(i, sdd, &sg); - cpumask_setall(sched_group_mask(sg)); + sg = get_group(i, sdd); - for_each_cpu(j, span) { - if (get_group(j, sdd, NULL) != group) - continue; - - cpumask_set_cpu(j, covered); - cpumask_set_cpu(j, sched_group_cpus(sg)); - } + cpumask_or(covered, covered, sched_group_cpus(sg)); if (!first) first = sg; @@ -904,6 +902,7 @@ build_sched_groups(struct sched_domain * last = sg; } last->next = first; + sd->groups = first; return 0; }