[RFC PATCH v1 7/8] sched/sched.h: move arch_scale_{freq,cpu}_capacity outside CONFIG_SMP

Juri Lelli
2017-07-05T09:00:51Z

Currently, frequency and cpu capacity scaling is only performed on
CONFIG_SMP systems (as CFS PELT signals are only present for such
systems). However, other scheduling classes want to do freq/cpu scaling,
and for !CONFIG_SMP configurations as well.

arch_scale_freq_capacity is useful to implement frequency scaling even
on !CONFIG_SMP platforms, so we simply move it outside CONFIG_SMP
ifdeffery.

Even if arch_scale_cpu_capacity is not useful on !CONFIG_SMP platforms,
we make a default implementation available for such configurations anyway
to simplify scheduler code doing CPU scale invariance.

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched/topology.h | 12 ++++++------
kernel/sched/sched.h | 13 ++++++++++---
2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 7d065abc7a47..953cf4f889ec 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -6,6 +6,12 @@
#include <linux/sched/idle.h>

/*
+ * Increase resolution of cpu_capacity calculations
+ */
+#define SCHED_CAPACITY_SHIFT SCHED_FIXEDPOINT_SHIFT
+#define SCHED_CAPACITY_SCALE (1L << SCHED_CAPACITY_SHIFT)
+
+/*
* sched-domains (multiprocessor balancing) declarations:
*/
#ifdef CONFIG_SMP
@@ -26,12 +32,6 @@
#define SD_OVERLAP 0x2000 /* sched_domains of this level overlap */
#define SD_NUMA 0x4000 /* cross-node balancing */

-/*
- * Increase resolution of cpu_capacity calculations
- */
-#define SCHED_CAPACITY_SHIFT SCHED_FIXEDPOINT_SHIFT
-#define SCHED_CAPACITY_SCALE (1L << SCHED_CAPACITY_SHIFT)
-
#ifdef CONFIG_SCHED_SMT
static inline int cpu_smt_flags(void)
{
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index ec5769288927..178f4a5df2fa 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1668,9 +1668,6 @@ static inline int hrtick_enabled(struct rq *rq)

#endif /* CONFIG_SCHED_HRTICK */

-#ifdef CONFIG_SMP
-extern void sched_avg_update(struct rq *rq);
-
#ifndef arch_scale_freq_capacity
static __always_inline
unsigned long arch_scale_freq_capacity(int cpu)
@@ -1679,6 +1676,9 @@ unsigned long arch_scale_freq_capacity(int cpu)
}
#endif

+#ifdef CONFIG_SMP
+extern void sched_avg_update(struct rq *rq);
+
#ifndef arch_scale_cpu_capacity
static __always_inline
unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
@@ -1696,6 +1696,13 @@ static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
sched_avg_update(rq);
}
#else
+#ifndef arch_scale_cpu_capacity
+static __always_inline
+unsigned long arch_scale_cpu_capacity(void __always_unused *sd, int cpu)
+{
+ return SCHED_CAPACITY_SCALE;
+}
+#endif
static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { }
static inline void sched_avg_update(struct rq *rq) { }
#endif
--
2.11.0