From 0bed612be638e41456cd8cb270a2b411a5b43d63 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Sat, 2 Apr 2016 01:08:43 +0200 Subject: [PATCH] cpufreq: sched: Helpers to add and remove update_util hooks Replace the single helper for adding and removing cpufreq utilization update hooks, cpufreq_set_update_util_data(), with a pair of helpers, cpufreq_add_update_util_hook() and cpufreq_remove_update_util_hook(), and modify the users of cpufreq_set_update_util_data() accordingly. With the new helpers, the code using them doesn't need to worry about the internals of struct update_util_data and in particular it doesn't need to worry about populating the func field in it properly upfront. Signed-off-by: Rafael J. Wysocki Acked-by: Viresh Kumar Acked-by: Peter Zijlstra (Intel) --- drivers/cpufreq/cpufreq_governor.c | 76 +++++++++++++++--------------- drivers/cpufreq/intel_pstate.c | 7 ++- include/linux/sched.h | 5 +- kernel/sched/cpufreq.c | 48 ++++++++++++++----- 4 files changed, 82 insertions(+), 54 deletions(-) diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 10a5cfeae8c5..3a0312f46027 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -258,43 +258,6 @@ unsigned int dbs_update(struct cpufreq_policy *policy) } EXPORT_SYMBOL_GPL(dbs_update); -static void gov_set_update_util(struct policy_dbs_info *policy_dbs, - unsigned int delay_us) -{ - struct cpufreq_policy *policy = policy_dbs->policy; - int cpu; - - gov_update_sample_delay(policy_dbs, delay_us); - policy_dbs->last_sample_time = 0; - - for_each_cpu(cpu, policy->cpus) { - struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu); - - cpufreq_set_update_util_data(cpu, &cdbs->update_util); - } -} - -static inline void gov_clear_update_util(struct cpufreq_policy *policy) -{ - int i; - - for_each_cpu(i, policy->cpus) - cpufreq_set_update_util_data(i, NULL); - - synchronize_sched(); -} - -static void gov_cancel_work(struct cpufreq_policy *policy) -{ - struct policy_dbs_info *policy_dbs = policy->governor_data; - - gov_clear_update_util(policy_dbs->policy); - irq_work_sync(&policy_dbs->irq_work); - cancel_work_sync(&policy_dbs->work); - atomic_set(&policy_dbs->work_count, 0); - policy_dbs->work_in_progress = false; -} - static void dbs_work_handler(struct work_struct *work) { struct policy_dbs_info *policy_dbs; @@ -382,6 +345,44 @@ static void dbs_update_util_handler(struct update_util_data *data, u64 time, irq_work_queue(&policy_dbs->irq_work); } +static void gov_set_update_util(struct policy_dbs_info *policy_dbs, + unsigned int delay_us) +{ + struct cpufreq_policy *policy = policy_dbs->policy; + int cpu; + + gov_update_sample_delay(policy_dbs, delay_us); + policy_dbs->last_sample_time = 0; + + for_each_cpu(cpu, policy->cpus) { + struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu); + + cpufreq_add_update_util_hook(cpu, &cdbs->update_util, + dbs_update_util_handler); + } +} + +static inline void gov_clear_update_util(struct cpufreq_policy *policy) +{ + int i; + + for_each_cpu(i, policy->cpus) + cpufreq_remove_update_util_hook(i); + + synchronize_sched(); +} + +static void gov_cancel_work(struct cpufreq_policy *policy) +{ + struct policy_dbs_info *policy_dbs = policy->governor_data; + + gov_clear_update_util(policy_dbs->policy); + irq_work_sync(&policy_dbs->irq_work); + cancel_work_sync(&policy_dbs->work); + atomic_set(&policy_dbs->work_count, 0); + policy_dbs->work_in_progress = false; +} + static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *policy, struct dbs_governor *gov) { @@ -404,7 +405,6 @@ static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *poli struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); j_cdbs->policy_dbs = policy_dbs; - j_cdbs->update_util.func = dbs_update_util_handler; } return policy_dbs; } diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 9ae159631f52..a38219527637 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1107,8 +1107,6 @@ static int intel_pstate_init_cpu(unsigned int cpunum) intel_pstate_busy_pid_reset(cpu); - cpu->update_util.func = intel_pstate_update_util; - pr_debug("intel_pstate: controlling: cpu %d\n", cpunum); return 0; @@ -1132,12 +1130,13 @@ static void intel_pstate_set_update_util_hook(unsigned int cpu_num) /* Prevent intel_pstate_update_util() from using stale data. */ cpu->sample.time = 0; - cpufreq_set_update_util_data(cpu_num, &cpu->update_util); + cpufreq_add_update_util_hook(cpu_num, &cpu->update_util, + intel_pstate_update_util); } static void intel_pstate_clear_update_util_hook(unsigned int cpu) { - cpufreq_set_update_util_data(cpu, NULL); + cpufreq_remove_update_util_hook(cpu); synchronize_sched(); } diff --git a/include/linux/sched.h b/include/linux/sched.h index 60bba7e032dc..1b8825922597 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -3240,7 +3240,10 @@ struct update_util_data { u64 time, unsigned long util, unsigned long max); }; -void cpufreq_set_update_util_data(int cpu, struct update_util_data *data); +void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data, + void (*func)(struct update_util_data *data, u64 time, + unsigned long util, unsigned long max)); +void cpufreq_remove_update_util_hook(int cpu); #endif /* CONFIG_CPU_FREQ */ #endif diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c index 928c4ba32f68..1141954e73b4 100644 --- a/kernel/sched/cpufreq.c +++ b/kernel/sched/cpufreq.c @@ -14,24 +14,50 @@ DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); /** - * cpufreq_set_update_util_data - Populate the CPU's update_util_data pointer. + * cpufreq_add_update_util_hook - Populate the CPU's update_util_data pointer. * @cpu: The CPU to set the pointer for. * @data: New pointer value. + * @func: Callback function to set for the CPU. * - * Set and publish the update_util_data pointer for the given CPU. That pointer - * points to a struct update_util_data object containing a callback function - * to call from cpufreq_update_util(). That function will be called from an RCU - * read-side critical section, so it must not sleep. + * Set and publish the update_util_data pointer for the given CPU. * - * Callers must use RCU-sched callbacks to free any memory that might be - * accessed via the old update_util_data pointer or invoke synchronize_sched() - * right after this function to avoid use-after-free. + * The update_util_data pointer of @cpu is set to @data and the callback + * function pointer in the target struct update_util_data is set to @func. + * That function will be called by cpufreq_update_util() from RCU-sched + * read-side critical sections, so it must not sleep. @data will always be + * passed to it as the first argument which allows the function to get to the + * target update_util_data structure and its container. + * + * The update_util_data pointer of @cpu must be NULL when this function is + * called or it will WARN() and return with no effect. */ -void cpufreq_set_update_util_data(int cpu, struct update_util_data *data) +void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data, + void (*func)(struct update_util_data *data, u64 time, + unsigned long util, unsigned long max)) { - if (WARN_ON(data && !data->func)) + if (WARN_ON(!data || !func)) return; + if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu))) + return; + + data->func = func; rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data); } -EXPORT_SYMBOL_GPL(cpufreq_set_update_util_data); +EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook); + +/** + * cpufreq_remove_update_util_hook - Clear the CPU's update_util_data pointer. + * @cpu: The CPU to clear the pointer for. + * + * Clear the update_util_data pointer for the given CPU. + * + * Callers must use RCU-sched callbacks to free any memory that might be + * accessed via the old update_util_data pointer or invoke synchronize_sched() + * right after this function to avoid use-after-free. + */ +void cpufreq_remove_update_util_hook(int cpu) +{ + rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), NULL); +} +EXPORT_SYMBOL_GPL(cpufreq_remove_update_util_hook); -- 2.20.1