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Commit adaf9fcd authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

cpufreq: Move scheduler-related code to the sched directory 



Create cpufreq.c under kernel/sched/ and move the cpufreq code
related to the scheduler to that file and to sched.h.

Redefine cpufreq_update_util() as a static inline function to avoid
function calls at its call sites in the scheduler code (as suggested
by Peter Zijlstra).

Also move the definition of struct update_util_data and declaration
of cpufreq_set_update_util_data() from include/linux/cpufreq.h to
include/linux/sched.h.

Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
parent 08f511fd

drivers/cpufreq/cpufreq.c

+0 −53
Original line number Diff line number Diff line
@@ -103,59 +103,6 @@ static struct cpufreq_driver *cpufreq_driver; 
static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);

static DEFINE_RWLOCK(cpufreq_driver_lock);



static DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);



/**

 * cpufreq_set_update_util_data - Populate the CPU's update_util_data pointer.

 * @cpu: The CPU to set the pointer for.

 * @data: New pointer value.

 *

 * 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.

 *

 * 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_set_update_util_data(int cpu, struct update_util_data *data)

{

	if (WARN_ON(data && !data->func))

		return;



	rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data);

}

EXPORT_SYMBOL_GPL(cpufreq_set_update_util_data);



/**

 * cpufreq_update_util - Take a note about CPU utilization changes.

 * @time: Current time.

 * @util: Current utilization.

 * @max: Utilization ceiling.

 *

 * This function is called by the scheduler on every invocation of

 * update_load_avg() on the CPU whose utilization is being updated.

 *

 * It can only be called from RCU-sched read-side critical sections.

 */

void cpufreq_update_util(u64 time, unsigned long util, unsigned long max)

{

	struct update_util_data *data;



#ifdef CONFIG_LOCKDEP

	WARN_ON(debug_locks && !rcu_read_lock_sched_held());

#endif



	data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data));

	/*

	 * If this isn't inside of an RCU-sched read-side critical section, data

	 * may become NULL after the check below.

	 */

	if (data)

		data->func(data, time, util, max);

}



/* Flag to suspend/resume CPUFreq governors */

static bool cpufreq_suspended;

drivers/cpufreq/cpufreq_governor.c

+1 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 


#include <linux/export.h>

#include <linux/kernel_stat.h>

#include <linux/sched.h>

#include <linux/slab.h>



#include "cpufreq_governor.h"

include/linux/cpufreq.h

+0 −34
Original line number Diff line number Diff line
@@ -146,36 +146,6 @@ static inline bool policy_is_shared(struct cpufreq_policy *policy) 
extern struct kobject *cpufreq_global_kobject;



#ifdef CONFIG_CPU_FREQ

void cpufreq_update_util(u64 time, unsigned long util, unsigned long max);



/**

 * cpufreq_trigger_update - Trigger CPU performance state evaluation if needed.

 * @time: Current time.

 *

 * The way cpufreq is currently arranged requires it to evaluate the CPU

 * performance state (frequency/voltage) on a regular basis to prevent it from

 * being stuck in a completely inadequate performance level for too long.

 * That is not guaranteed to happen if the updates are only triggered from CFS,

 * though, because they may not be coming in if RT or deadline tasks are active

 * all the time (or there are RT and DL tasks only).

 *

 * As a workaround for that issue, this function is called by the RT and DL

 * sched classes to trigger extra cpufreq updates to prevent it from stalling,

 * but that really is a band-aid.  Going forward it should be replaced with

 * solutions targeted more specifically at RT and DL tasks.

 */

static inline void cpufreq_trigger_update(u64 time)

{

	cpufreq_update_util(time, ULONG_MAX, 0);

}



struct update_util_data {

	void (*func)(struct update_util_data *data,

		     u64 time, unsigned long util, unsigned long max);

};



void cpufreq_set_update_util_data(int cpu, struct update_util_data *data);



unsigned int cpufreq_get(unsigned int cpu);

unsigned int cpufreq_quick_get(unsigned int cpu);

unsigned int cpufreq_quick_get_max(unsigned int cpu);
@@ -187,10 +157,6 @@ int cpufreq_update_policy(unsigned int cpu); 
bool have_governor_per_policy(void);

struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);

#else

static inline void cpufreq_update_util(u64 time, unsigned long util,

				       unsigned long max) {}

static inline void cpufreq_trigger_update(u64 time) {}



static inline unsigned int cpufreq_get(unsigned int cpu)

{

	return 0;

include/linux/sched.h

+9 −0
Original line number Diff line number Diff line
@@ -3207,4 +3207,13 @@ static inline unsigned long rlimit_max(unsigned int limit) 
	return task_rlimit_max(current, limit);

}



#ifdef CONFIG_CPU_FREQ

struct update_util_data {

	void (*func)(struct update_util_data *data,

		     u64 time, unsigned long util, unsigned long max);

};



void cpufreq_set_update_util_data(int cpu, struct update_util_data *data);

#endif /* CONFIG_CPU_FREQ */



#endif

kernel/sched/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -19,3 +19,4 @@ obj-$(CONFIG_SCHED_AUTOGROUP) += auto_group.o 
obj-$(CONFIG_SCHEDSTATS) += stats.o

obj-$(CONFIG_SCHED_DEBUG) += debug.o

obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o

obj-$(CONFIG_CPU_FREQ) += cpufreq.o