From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: [PATCH V5 14/14] cpufreq: Restart governor as soon as possible Date: Mon, 18 May 2015 10:43:37 +0530 Message-ID: <13d7278bf92d9c7b4c9a27264d1dd5cc2e350b05.1431924457.git.viresh.kumar@linaro.org> References: Return-path: Received: from mail-pa0-f48.google.com ([209.85.220.48]:35491 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751183AbbERFOo (ORCPT ); Mon, 18 May 2015 01:14:44 -0400 Received: by pacwv17 with SMTP id wv17so136037512pac.2 for ; Sun, 17 May 2015 22:14:44 -0700 (PDT) In-Reply-To: In-Reply-To: References: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Rafael Wysocki Cc: linaro-kernel@lists.linaro.org, linux-pm@vger.kernel.org, sboyd@codeaurora.org, prarit@redhat.com, skannan@codeaurora.org, Srivatsa Bhat , Viresh Kumar On cpu hot-unplug, we don't need to wait for POST_DEAD notification to restart the governor if the policy has atleast one online cpu left. We can restart the governor right from the DOWN_PREPARE notification instead. [ Something similar attempted by Saravana earlier ] Signed-off-by: Viresh Kumar --- drivers/cpufreq/cpufreq.c | 58 ++++++++++++++++++++--------------------------- 1 file changed, 24 insertions(+), 34 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index b030432cbfad..8d64b5e74ab2 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1398,8 +1398,8 @@ static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif) static int __cpufreq_remove_dev_prepare(struct device *dev, struct subsys_interface *sif) { - unsigned int cpu = dev->id, cpus; - int ret; + unsigned int cpu = dev->id; + int ret = 0; struct cpufreq_policy *policy; pr_debug("%s: unregistering CPU %u\n", __func__, cpu); @@ -1419,26 +1419,33 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, } down_write(&policy->rwsem); - cpus = cpumask_weight(policy->cpus); + cpumask_clear_cpu(cpu, policy->cpus); - if (has_target() && cpus == 1) - strncpy(policy->last_governor, policy->governor->name, - CPUFREQ_NAME_LEN); + if (policy_is_inactive(policy)) { + if (has_target()) + strncpy(policy->last_governor, policy->governor->name, + CPUFREQ_NAME_LEN); + } else if (cpu == policy->cpu) { + /* Nominate new CPU */ + policy->cpu = cpumask_any(policy->cpus); + } up_write(&policy->rwsem); - if (cpu != policy->cpu) - return 0; + /* Start governor again for active policy */ + if (!policy_is_inactive(policy)) { + if (has_target()) { + ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); + if (!ret) + ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); - if (cpus > 1) { - /* Nominate new CPU */ - down_write(&policy->rwsem); - policy->cpu = cpumask_any_but(policy->cpus, cpu); - up_write(&policy->rwsem); + if (ret) + pr_err("%s: Failed to start governor\n", __func__); + } } else if (cpufreq_driver->stop_cpu) { cpufreq_driver->stop_cpu(policy); } - return 0; + return ret; } static int __cpufreq_remove_dev_finish(struct device *dev, @@ -1446,33 +1453,16 @@ static int __cpufreq_remove_dev_finish(struct device *dev, { unsigned int cpu = dev->id; int ret; - struct cpufreq_policy *policy = cpufreq_cpu_get_raw(cpu); + struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu); if (!policy) { pr_debug("%s: No cpu_data found\n", __func__); return -EINVAL; } - down_write(&policy->rwsem); - cpumask_clear_cpu(cpu, policy->cpus); - up_write(&policy->rwsem); - - /* Not the last cpu of policy, start governor again ? */ - if (!policy_is_inactive(policy)) { - if (!has_target()) - return 0; - - ret = __cpufreq_governor(policy, CPUFREQ_GOV_START); - if (!ret) - ret = __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS); - - if (ret) { - pr_err("%s: Failed to start governor\n", __func__); - return ret; - } - + /* Only proceed for inactive policies */ + if (!policy_is_inactive(policy)) return 0; - } /* If cpu is last user of policy, free policy */ if (has_target()) { -- 2.4.0