diff options
author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-04-01 23:08:43 (GMT) |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-04-01 23:08:43 (GMT) |
commit | 0bed612be638e41456cd8cb270a2b411a5b43d63 (patch) | |
tree | 02b294dcea4c15378525c456314af36334a87f4a /kernel/sched | |
parent | 9fa64d6424adabf0e3a546ae24d01a62a927b342 (diff) | |
download | linux-0bed612be638e41456cd8cb270a2b411a5b43d63.tar.xz |
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 <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r-- | kernel/sched/cpufreq.c | 48 |
1 files changed, 37 insertions, 11 deletions
diff --git a/kernel/sched/cpufreq.c b/kernel/sched/cpufreq.c index 928c4ba..1141954 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); |