From patchwork Mon Dec 3 09:56:22 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Quentin Perret X-Patchwork-Id: 10709035 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 73FE614E2 for ; Mon, 3 Dec 2018 09:57:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 63DF72A94F for ; Mon, 3 Dec 2018 09:57:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 57C4D2AEBE; Mon, 3 Dec 2018 09:57:59 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D89292AEB8 for ; Mon, 3 Dec 2018 09:57:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726250AbeLCJ5i (ORCPT ); Mon, 3 Dec 2018 04:57:38 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:32792 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725888AbeLCJ5h (ORCPT ); Mon, 3 Dec 2018 04:57:37 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B5ADF169E; Mon, 3 Dec 2018 01:57:17 -0800 (PST) Received: from queper01-lin.cambridge.arm.com (queper01-lin.cambridge.arm.com [10.1.195.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 992C33F59C; Mon, 3 Dec 2018 01:57:13 -0800 (PST) From: Quentin Perret To: peterz@infradead.org, rjw@rjwysocki.net, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: gregkh@linuxfoundation.org, mingo@redhat.com, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, chris.redpath@arm.com, patrick.bellasi@arm.com, valentin.schneider@arm.com, vincent.guittot@linaro.org, thara.gopinath@linaro.org, viresh.kumar@linaro.org, tkjos@google.com, joel@joelfernandes.org, smuckle@google.com, adharmap@codeaurora.org, skannan@codeaurora.org, pkondeti@codeaurora.org, juri.lelli@redhat.com, edubezval@gmail.com, srinivas.pandruvada@linux.intel.com, currojerez@riseup.net, javi.merino@kernel.org, quentin.perret@arm.com Subject: [PATCH v10 09/15] sched: Introduce sched_energy_present static key Date: Mon, 3 Dec 2018 09:56:22 +0000 Message-Id: <20181203095628.11858-10-quentin.perret@arm.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181203095628.11858-1-quentin.perret@arm.com> References: <20181203095628.11858-1-quentin.perret@arm.com> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In order to make sure Energy Aware Scheduling (EAS) will not impact systems where no Energy Model is available, introduce a static key guarding the access to EAS code. Since EAS is enabled on a per-root-domain basis, the static key is enabled when at least one root domain meets all conditions for EAS. Cc: Ingo Molnar Cc: Peter Zijlstra Signed-off-by: Quentin Perret --- kernel/sched/sched.h | 4 ++++ kernel/sched/topology.c | 28 ++++++++++++++++++++++++---- 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 6236081d68bf..8decb3bc0e3f 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2298,3 +2298,7 @@ unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned #else #define perf_domain_span(pd) NULL #endif + +#ifdef CONFIG_SMP +extern struct static_key_false sched_energy_present; +#endif diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 70492d4bfed6..24d211ca384d 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -201,6 +201,7 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) return 1; } +DEFINE_STATIC_KEY_FALSE(sched_energy_present); #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) DEFINE_MUTEX(sched_energy_mutex); bool sched_energy_update; @@ -273,6 +274,19 @@ static void destroy_perf_domain_rcu(struct rcu_head *rp) free_pd(pd); } +static void sched_energy_set(bool has_eas) +{ + if (!has_eas && static_branch_unlikely(&sched_energy_present)) { + if (sched_debug()) + pr_info("%s: stopping EAS\n", __func__); + static_branch_disable_cpuslocked(&sched_energy_present); + } else if (has_eas && !static_branch_unlikely(&sched_energy_present)) { + if (sched_debug()) + pr_info("%s: starting EAS\n", __func__); + static_branch_enable_cpuslocked(&sched_energy_present); + } +} + /* * EAS can be used on a root domain if it meets all the following conditions: * 1. an Energy Model (EM) is available; @@ -299,7 +313,7 @@ static void destroy_perf_domain_rcu(struct rcu_head *rp) #define EM_MAX_COMPLEXITY 2048 extern struct cpufreq_governor schedutil_gov; -static void build_perf_domains(const struct cpumask *cpu_map) +static bool build_perf_domains(const struct cpumask *cpu_map) { int i, nr_pd = 0, nr_cs = 0, nr_cpus = cpumask_weight(cpu_map); struct perf_domain *pd = NULL, *tmp; @@ -365,7 +379,7 @@ static void build_perf_domains(const struct cpumask *cpu_map) if (tmp) call_rcu(&tmp->rcu, destroy_perf_domain_rcu); - return; + return !!pd; free: free_pd(pd); @@ -373,6 +387,8 @@ static void build_perf_domains(const struct cpumask *cpu_map) rcu_assign_pointer(rd->pd, NULL); if (tmp) call_rcu(&tmp->rcu, destroy_perf_domain_rcu); + + return false; } #else static void free_pd(struct perf_domain *pd) { } @@ -2116,6 +2132,7 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], struct sched_domain_attr *dattr_new) { + bool __maybe_unused has_eas = false; int i, j, n; int new_topology; @@ -2179,14 +2196,17 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], for (i = 0; i < ndoms_new; i++) { for (j = 0; j < n && !sched_energy_update; j++) { if (cpumask_equal(doms_new[i], doms_cur[j]) && - cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) + cpu_rq(cpumask_first(doms_cur[j]))->rd->pd) { + has_eas = true; goto match3; + } } /* No match - add perf. domains for a new rd */ - build_perf_domains(doms_new[i]); + has_eas |= build_perf_domains(doms_new[i]); match3: ; } + sched_energy_set(has_eas); #endif /* Remember the new sched domains: */