sched/topology: Consolidate and clean up access to a CPU's max compute capacity

Remove the rq::cpu_capacity_orig field and use arch_scale_cpu_capacity()
instead.

The scheduler uses 3 methods to get access to a CPU's max compute capacity:

 - arch_scale_cpu_capacity(cpu) which is the default way to get a CPU's capacity.

 - cpu_capacity_orig field which is periodically updated with
   arch_scale_cpu_capacity().

 - capacity_orig_of(cpu) which encapsulates rq->cpu_capacity_orig.

There is no real need to save the value returned by arch_scale_cpu_capacity()
in struct rq. arch_scale_cpu_capacity() returns:

 - either a per_cpu variable.

 - or a const value for systems which have only one capacity.

Remove rq::cpu_capacity_orig and use arch_scale_cpu_capacity() everywhere.

No functional changes.

Some performance tests on Arm64:

  - small SMP device (hikey): no noticeable changes
  - HMP device (RB5):         hackbench shows minor improvement (1-2%)
  - large smp (thx2):         hackbench and tbench shows minor improvement (1%)

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20231009103621.374412-2-vincent.guittot@linaro.org

1 files changed, 0 insertions, 6 deletions

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 515eb4cffd5e..7e7fedcfc580 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1033,7 +1033,6 @@ struct rq {
 	struct sched_domain __rcu	*sd;
 
 	unsigned long		cpu_capacity;
-	unsigned long		cpu_capacity_orig;
 
 	struct balance_callback *balance_callback;
 
@@ -2967,11 +2966,6 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
 #endif
 
 #ifdef CONFIG_SMP
-static inline unsigned long capacity_orig_of(int cpu)
-{
-	return cpu_rq(cpu)->cpu_capacity_orig;
-}
-
 /**
  * enum cpu_util_type - CPU utilization type
  * @FREQUENCY_UTIL:	Utilization used to select frequency