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Subject[PATCH 1/3] sched: Introduce sched_asym_cpucap_active()
Date
Create an inline helper for conditional code to be only executed on
asymmetric CPU capacity systems. This makes these (currently ~10 and
future) conditions a lot more readable.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
---
kernel/sched/cpudeadline.c | 2 +-
kernel/sched/deadline.c | 4 ++--
kernel/sched/fair.c | 8 ++++----
kernel/sched/rt.c | 4 ++--
kernel/sched/sched.h | 5 +++++
5 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 02d970a879ed..57c92d751bcd 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -123,7 +123,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
unsigned long cap, max_cap = 0;
int cpu, max_cpu = -1;

- if (!static_branch_unlikely(&sched_asym_cpucapacity))
+ if (!sched_asym_cpucap_active())
return 1;

/* Ensure the capacity of the CPUs fits the task. */
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 5867e186c39a..3f9d90b8a8b6 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -144,7 +144,7 @@ static inline unsigned long __dl_bw_capacity(int i)
*/
static inline unsigned long dl_bw_capacity(int i)
{
- if (!static_branch_unlikely(&sched_asym_cpucapacity) &&
+ if (!sched_asym_cpucap_active() &&
capacity_orig_of(i) == SCHED_CAPACITY_SCALE) {
return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT;
} else {
@@ -1846,7 +1846,7 @@ select_task_rq_dl(struct task_struct *p, int cpu, int flags)
* Take the capacity of the CPU into account to
* ensure it fits the requirement of the task.
*/
- if (static_branch_unlikely(&sched_asym_cpucapacity))
+ if (sched_asym_cpucap_active())
select_rq |= !dl_task_fits_capacity(p, cpu);

if (select_rq) {
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index f80ae86bb404..f32e0866b9c9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4211,7 +4211,7 @@ static inline int task_fits_capacity(struct task_struct *p,

static inline void update_misfit_status(struct task_struct *p, struct rq *rq)
{
- if (!static_branch_unlikely(&sched_asym_cpucapacity))
+ if (!sched_asym_cpucap_active())
return;

if (!p || p->nr_cpus_allowed == 1) {
@@ -6452,7 +6452,7 @@ select_idle_capacity(struct task_struct *p, struct sched_domain *sd, int target)

static inline bool asym_fits_capacity(unsigned long task_util, int cpu)
{
- if (static_branch_unlikely(&sched_asym_cpucapacity))
+ if (sched_asym_cpucap_active())
return fits_capacity(task_util, capacity_of(cpu));

return true;
@@ -6472,7 +6472,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
* On asymmetric system, update task utilization because we will check
* that the task fits with cpu's capacity.
*/
- if (static_branch_unlikely(&sched_asym_cpucapacity)) {
+ if (sched_asym_cpucap_active()) {
sync_entity_load_avg(&p->se);
task_util = uclamp_task_util(p);
}
@@ -6526,7 +6526,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
* For asymmetric CPU capacity systems, our domain of interest is
* sd_asym_cpucapacity rather than sd_llc.
*/
- if (static_branch_unlikely(&sched_asym_cpucapacity)) {
+ if (sched_asym_cpucap_active()) {
sd = rcu_dereference(per_cpu(sd_asym_cpucapacity, target));
/*
* On an asymmetric CPU capacity system where an exclusive
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 8c9ed9664840..f0c297c1bd78 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -509,7 +509,7 @@ static inline bool rt_task_fits_capacity(struct task_struct *p, int cpu)
unsigned int cpu_cap;

/* Only heterogeneous systems can benefit from this check */
- if (!static_branch_unlikely(&sched_asym_cpucapacity))
+ if (!sched_asym_cpucap_active())
return true;

min_cap = uclamp_eff_value(p, UCLAMP_MIN);
@@ -1894,7 +1894,7 @@ static int find_lowest_rq(struct task_struct *task)
* If we're on asym system ensure we consider the different capacities
* of the CPUs when searching for the lowest_mask.
*/
- if (static_branch_unlikely(&sched_asym_cpucapacity)) {
+ if (sched_asym_cpucap_active()) {

ret = cpupri_find_fitness(&task_rq(task)->rd->cpupri,
task, lowest_mask,
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 02c970501295..79f65a6799c6 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1759,6 +1759,11 @@ DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_packing);
DECLARE_PER_CPU(struct sched_domain __rcu *, sd_asym_cpucapacity);
extern struct static_key_false sched_asym_cpucapacity;

+static __always_inline bool sched_asym_cpucap_active(void)
+{
+ return static_branch_unlikely(&sched_asym_cpucapacity);
+}
+
struct sched_group_capacity {
atomic_t ref;
/*
--
2.25.1
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