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Subject[RFC][PATCH 1/7] cpufreq / sched: Make schedutil access utilization data directly
Date
From: Peter Zijlstra <peterz@infradead.org>

Since the schedutil governor is part of the scheduler proper, it can
access scheduler data directly.

This allows us to remove the util and max arguments of
cpufreq_update_util(), since only the schedutil governor will use
those, which leads to some text reduction:

43595 1226 24 44845 af2d defconfig-build/kernel/sched/fair.o.pre
42907 1226 24 44157 ac7d defconfig-build/kernel/sched/fair.o.post

Of course, we get more text in schedutil in return, but we can
benefit from not being tied to those two parameters by doing a very
coarse deadline reservation.

[ rjw: Subject/changelog + rebase, minor updates ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/cpufreq/cpufreq_governor.c | 3 --
drivers/cpufreq/intel_pstate.c | 3 --
include/linux/sched.h | 6 +----
kernel/sched/core.c | 4 +--
kernel/sched/cpufreq.c | 3 --
kernel/sched/cpufreq_schedutil.c | 40 +++++++++++++++++++++++++++++++++----
kernel/sched/fair.c | 11 +++-------
kernel/sched/sched.h | 17 +++++++--------
8 files changed, 55 insertions(+), 32 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq_governor.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_governor.c
+++ linux-pm/drivers/cpufreq/cpufreq_governor.c
@@ -259,8 +259,7 @@ static void dbs_irq_work(struct irq_work
schedule_work_on(smp_processor_id(), &policy_dbs->work);
}

-static void dbs_update_util_handler(struct update_util_data *data, u64 time,
- unsigned long util, unsigned long max)
+static void dbs_update_util_handler(struct update_util_data *data, u64 time)
{
struct cpu_dbs_info *cdbs = container_of(data, struct cpu_dbs_info, update_util);
struct policy_dbs_info *policy_dbs = cdbs->policy_dbs;
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -1328,8 +1328,7 @@ static inline void intel_pstate_adjust_b
get_avg_frequency(cpu));
}

-static void intel_pstate_update_util(struct update_util_data *data, u64 time,
- unsigned long util, unsigned long max)
+static void intel_pstate_update_util(struct update_util_data *data, u64 time)
{
struct cpudata *cpu = container_of(data, struct cpudata, update_util);
u64 delta_ns = time - cpu->sample.time;
Index: linux-pm/include/linux/sched.h
===================================================================
--- linux-pm.orig/include/linux/sched.h
+++ linux-pm/include/linux/sched.h
@@ -3377,13 +3377,11 @@ static inline unsigned long rlimit_max(u

#ifdef CONFIG_CPU_FREQ
struct update_util_data {
- void (*func)(struct update_util_data *data,
- u64 time, unsigned long util, unsigned long max);
+ void (*func)(struct update_util_data *data, u64 time);
};

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 (*func)(struct update_util_data *data, u64 time));
void cpufreq_remove_update_util_hook(int cpu);
#endif /* CONFIG_CPU_FREQ */

Index: linux-pm/kernel/sched/cpufreq.c
===================================================================
--- linux-pm.orig/kernel/sched/cpufreq.c
+++ linux-pm/kernel/sched/cpufreq.c
@@ -32,8 +32,7 @@ DEFINE_PER_CPU(struct update_util_data *
* called or it will WARN() and return with no effect.
*/
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 (*func)(struct update_util_data *data, u64 time))
{
if (WARN_ON(!data || !func))
return;
Index: linux-pm/kernel/sched/cpufreq_schedutil.c
===================================================================
--- linux-pm.orig/kernel/sched/cpufreq_schedutil.c
+++ linux-pm/kernel/sched/cpufreq_schedutil.c
@@ -144,17 +144,47 @@ static unsigned int get_next_freq(struct
return cpufreq_driver_resolve_freq(policy, freq);
}

-static void sugov_update_single(struct update_util_data *hook, u64 time,
- unsigned long util, unsigned long max)
+static void sugov_get_util(unsigned long *util, unsigned long *max)
+{
+ unsigned long dl_util, dl_max;
+ unsigned long cfs_util, cfs_max;
+ int cpu = smp_processor_id();
+ struct dl_bw *dl_bw = dl_bw_of(cpu);
+ struct rq *rq = this_rq();
+
+ if (rt_prio(current->prio)) {
+ *util = ULONG_MAX;
+ return;
+ }
+
+ dl_max = dl_bw_cpus(cpu) << 20;
+ dl_util = dl_bw->total_bw;
+
+ cfs_max = rq->cpu_capacity_orig;
+ cfs_util = min(rq->cfs.avg.util_avg, cfs_max);
+
+ if (cfs_util * dl_max > dl_util * cfs_max) {
+ *util = cfs_util;
+ *max = cfs_max;
+ } else {
+ *util = dl_util;
+ *max = dl_max;
+ }
+}
+
+static void sugov_update_single(struct update_util_data *hook, u64 time)
{
struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
struct cpufreq_policy *policy = sg_policy->policy;
+ unsigned long util, max;
unsigned int next_f;

if (!sugov_should_update_freq(sg_policy, time))
return;

+ sugov_get_util(&util, &max);
+
next_f = util == ULONG_MAX ? policy->cpuinfo.max_freq :
get_next_freq(sg_cpu, util, max);
sugov_update_commit(sg_policy, time, next_f);
@@ -206,13 +236,15 @@ static unsigned int sugov_next_freq_shar
return get_next_freq(sg_cpu, util, max);
}

-static void sugov_update_shared(struct update_util_data *hook, u64 time,
- unsigned long util, unsigned long max)
+static void sugov_update_shared(struct update_util_data *hook, u64 time)
{
struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
+ unsigned long util, max;
unsigned int next_f;

+ sugov_get_util(&util, &max);
+
raw_spin_lock(&sg_policy->update_lock);

sg_cpu->util = util;
Index: linux-pm/kernel/sched/fair.c
===================================================================
--- linux-pm.orig/kernel/sched/fair.c
+++ linux-pm/kernel/sched/fair.c
@@ -2870,11 +2870,8 @@ static inline u64 cfs_rq_clock_task(stru

static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
{
- struct rq *rq = rq_of(cfs_rq);
- int cpu = cpu_of(rq);
-
- if (cpu == smp_processor_id() && &rq->cfs == cfs_rq) {
- unsigned long max = rq->cpu_capacity_orig;
+ if (&this_rq()->cfs == cfs_rq) {
+ struct rq *rq = rq_of(cfs_rq);

/*
* There are a few boundary cases this might miss but it should
@@ -2892,8 +2889,8 @@ static inline void cfs_rq_util_change(st
*
* See cpu_util().
*/
- cpufreq_update_util(rq_clock(rq),
- min(cfs_rq->avg.util_avg, max), max);
+ if (cpu_of(rq) == smp_processor_id())
+ cpufreq_update_util(rq_clock(rq));
}
}

Index: linux-pm/kernel/sched/sched.h
===================================================================
--- linux-pm.orig/kernel/sched/sched.h
+++ linux-pm/kernel/sched/sched.h
@@ -190,6 +190,7 @@ static inline int dl_bandwidth_enabled(v
}

extern struct dl_bw *dl_bw_of(int i);
+extern int dl_bw_cpus(int i);

struct dl_bw {
raw_spinlock_t lock;
@@ -1760,21 +1761,19 @@ DECLARE_PER_CPU(struct 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.
*/
-static inline void cpufreq_update_util(u64 time, unsigned long util, unsigned long max)
+static inline void cpufreq_update_util(u64 time)
{
- struct update_util_data *data;
+ struct update_util_data *data;

- data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data));
- if (data)
- data->func(data, time, util, max);
+ data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data));
+ if (data)
+ data->func(data, time);
}

/**
@@ -1795,10 +1794,10 @@ static inline void cpufreq_update_util(u
*/
static inline void cpufreq_trigger_update(u64 time)
{
- cpufreq_update_util(time, ULONG_MAX, 0);
+ cpufreq_update_util(time);
}
#else
-static inline void cpufreq_update_util(u64 time, unsigned long util, unsigned long max) {}
+static inline void cpufreq_update_util(u64 time) {}
static inline void cpufreq_trigger_update(u64 time) {}
#endif /* CONFIG_CPU_FREQ */

Index: linux-pm/kernel/sched/core.c
===================================================================
--- linux-pm.orig/kernel/sched/core.c
+++ linux-pm/kernel/sched/core.c
@@ -2438,7 +2438,7 @@ inline struct dl_bw *dl_bw_of(int i)
return &cpu_rq(i)->rd->dl_bw;
}

-static inline int dl_bw_cpus(int i)
+int dl_bw_cpus(int i)
{
struct root_domain *rd = cpu_rq(i)->rd;
int cpus = 0;
@@ -2456,7 +2456,7 @@ inline struct dl_bw *dl_bw_of(int i)
return &cpu_rq(i)->dl.dl_bw;
}

-static inline int dl_bw_cpus(int i)
+int dl_bw_cpus(int i)
{
return 1;
}
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