[RFC PATCH 1/6] sched/fair: Create util_fits_capacity()

Dietmar Eggemann
2018-03-20T09:43:07Z

The functionality that a given utilization fits into a given capacity
is factored out into a separate function.

Currently it is only used in wake_cap() but will be re-used to figure
out if a cpu or a scheduler group is over-utilized.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
---
kernel/sched/fair.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 3582117e1580..bf7b485ddf60 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6374,6 +6374,11 @@ static unsigned long cpu_util_wake(int cpu, struct task_struct *p)
return (util >= capacity) ? capacity : util;
}

+static inline int util_fits_capacity(unsigned long util, unsigned long capacity)
+{
+ return capacity * 1024 > util * capacity_margin;
+}
+
/*
* Disable WAKE_AFFINE in the case where task @p doesn't fit in the
* capacity of either the waking CPU @cpu or the previous CPU @prev_cpu.
@@ -6395,7 +6400,7 @@ static int wake_cap(struct task_struct *p, int cpu, int prev_cpu)
/* Bring task utilization in sync with prev_cpu */
sync_entity_load_avg(&p->se);

- return min_cap * 1024 < task_util(p) * capacity_margin;
+ return !util_fits_capacity(task_util(p), min_cap);
}

/*
--
2.11.0