alistair23-linux/include/linux/sched/cpufreq.h
Vincent Guittot a4f9a0e51b sched/fair: Remove redundant call to cpufreq_update_util()
With commit

  bef69dd878 ("sched/cpufreq: Move the cfs_rq_util_change() call to cpufreq_update_util()")

update_load_avg() has become the central point for calling cpufreq
(not including the update of blocked load). This change helps to
simplify further the number of calls to cpufreq_update_util() and to
remove last redundant ones. With update_load_avg(), we are now sure
that cpufreq_update_util() will be called after every task attachment
to a cfs_rq and especially after propagating this event down to the
util_avg of the root cfs_rq, which is the level that is used by
cpufreq governors like schedutil to set the frequency of a CPU.

The SCHED_CPUFREQ_MIGRATION flag forces an early call to cpufreq when
the migration happens in a cgroup whereas util_avg of root cfs_rq is
not yet updated and this call is duplicated with the one that happens
immediately after when the migration event reaches the root cfs_rq.
The dedicated flag SCHED_CPUFREQ_MIGRATION is now useless and can be
removed. The interface of attach_entity_load_avg() can also be
simplified accordingly.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/1579083620-24943-1-git-send-email-vincent.guittot@linaro.org
2020-01-17 10:19:22 +01:00

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C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SCHED_CPUFREQ_H
#define _LINUX_SCHED_CPUFREQ_H
#include <linux/types.h>
/*
* Interface between cpufreq drivers and the scheduler:
*/
#define SCHED_CPUFREQ_IOWAIT (1U << 0)
#ifdef CONFIG_CPU_FREQ
struct cpufreq_policy;
struct update_util_data {
void (*func)(struct update_util_data *data, u64 time, unsigned int flags);
};
void cpufreq_add_update_util_hook(int cpu, struct update_util_data *data,
void (*func)(struct update_util_data *data, u64 time,
unsigned int flags));
void cpufreq_remove_update_util_hook(int cpu);
bool cpufreq_this_cpu_can_update(struct cpufreq_policy *policy);
static inline unsigned long map_util_freq(unsigned long util,
unsigned long freq, unsigned long cap)
{
return (freq + (freq >> 2)) * util / cap;
}
#endif /* CONFIG_CPU_FREQ */
#endif /* _LINUX_SCHED_CPUFREQ_H */