[RFCv5 PATCH 04/46] sched: Convert arch_scale_cpu_capacity() from weak function to #define

Morten Rasmussen
2015-07-07T18:23:00Z

Bring arch_scale_cpu_capacity() in line with the recent change of its
arch_scale_freq_capacity() sibling in commit dfbca41f3479 ("sched:
Optimize freq invariant accounting") from weak function to #define to
allow inlining of the function.

While at it, remove the ARCH_CAPACITY sched_feature as well. With the
change to #define there isn't a straightforward way to allow runtime
switch between an arch implementation and the default implementation of
arch_scale_cpu_capacity() using sched_feature. The default was to use
the arch-specific implementation, but only the arm architecture provided
one.

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
---
kernel/sched/fair.c | 22 +---------------------
kernel/sched/features.h | 5 -----
kernel/sched/sched.h | 11 +++++++++++
3 files changed, 12 insertions(+), 26 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 376ec75..5b4e8c1 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6238,19 +6238,6 @@ static inline int get_sd_load_idx(struct sched_domain *sd,
return load_idx;
}

-static unsigned long default_scale_cpu_capacity(struct sched_domain *sd, int cpu)
-{
- if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
- return sd->smt_gain / sd->span_weight;
-
- return SCHED_CAPACITY_SCALE;
-}
-
-unsigned long __weak arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
-{
- return default_scale_cpu_capacity(sd, cpu);
-}
-
static unsigned long scale_rt_capacity(int cpu)
{
struct rq *rq = cpu_rq(cpu);
@@ -6280,16 +6267,9 @@ static unsigned long scale_rt_capacity(int cpu)

static void update_cpu_capacity(struct sched_domain *sd, int cpu)
{
- unsigned long capacity = SCHED_CAPACITY_SCALE;
+ unsigned long capacity = arch_scale_cpu_capacity(sd, cpu);
struct sched_group *sdg = sd->groups;

- if (sched_feat(ARCH_CAPACITY))
- capacity *= arch_scale_cpu_capacity(sd, cpu);
- else
- capacity *= default_scale_cpu_capacity(sd, cpu);
-
- capacity >>= SCHED_CAPACITY_SHIFT;
-
cpu_rq(cpu)->cpu_capacity_orig = capacity;

capacity *= scale_rt_capacity(cpu);
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 91e33cd..03d8072 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -36,11 +36,6 @@ SCHED_FEAT(CACHE_HOT_BUDDY, true)
*/
SCHED_FEAT(WAKEUP_PREEMPTION, true)

-/*
- * Use arch dependent cpu capacity functions
- */
-SCHED_FEAT(ARCH_CAPACITY, true)
-
SCHED_FEAT(HRTICK, false)
SCHED_FEAT(DOUBLE_TICK, false)
SCHED_FEAT(LB_BIAS, true)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index d62b288..af08a82 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1399,6 +1399,17 @@ unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
}
#endif

+#ifndef arch_scale_cpu_capacity
+static __always_inline
+unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
+{
+ if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
+ return sd->smt_gain / sd->span_weight;
+
+ return SCHED_CAPACITY_SCALE;
+}
+#endif
+
static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
{
rq->rt_avg += rt_delta * arch_scale_freq_capacity(NULL, cpu_of(rq));
--
1.9.1