From mboxrd@z Thu Jan 1 00:00:00 1970 From: skannan@codeaurora.org (Saravana Kannan) Date: Thu, 24 Jul 2014 18:07:24 -0700 Subject: [PATCH v4 1/5] cpufreq: Don't wait for CPU to going offline to restart governor In-Reply-To: <1406250448-470-1-git-send-email-skannan@codeaurora.org> References: <1406250448-470-1-git-send-email-skannan@codeaurora.org> Message-ID: <1406250448-470-2-git-send-email-skannan@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org There's no need to wait for the CPU going down to fully go offline to restart the governor. We can stop the governor, change policy->cpus and immediately restart the governor. This should reduce the time without any CPUfreq monitoring and also help future patches with simplifying the code. Signed-off-by: Saravana Kannan --- drivers/cpufreq/cpufreq.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 62259d2..ee0eb7b 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1390,6 +1390,21 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, cpufreq_driver->stop_cpu(policy); } + down_write(&policy->rwsem); + cpumask_clear_cpu(cpu, policy->cpus); + up_write(&policy->rwsem); + + if (cpus > 1 && has_target()) { + 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; + } + } + return 0; } @@ -1410,15 +1425,12 @@ static int __cpufreq_remove_dev_finish(struct device *dev, return -EINVAL; } - down_write(&policy->rwsem); + down_read(&policy->rwsem); cpus = cpumask_weight(policy->cpus); - - if (cpus > 1) - cpumask_clear_cpu(cpu, policy->cpus); - up_write(&policy->rwsem); + up_read(&policy->rwsem); /* If cpu is last user of policy, free policy */ - if (cpus == 1) { + if (cpus == 0) { if (has_target()) { ret = __cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT); @@ -1447,15 +1459,6 @@ static int __cpufreq_remove_dev_finish(struct device *dev, if (!cpufreq_suspended) cpufreq_policy_free(policy); - } else if (has_target()) { - 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; - } } per_cpu(cpufreq_cpu_data, cpu) = NULL; -- 1.8.2.1 The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation