From ca6d75e6908efbc350d536e0b496ebdac36b20d2 Mon Sep 17 00:00:00 2001
From: Vincent Guittot <vincent.guittot@linaro.org>
Date: Fri, 27 Feb 2015 16:54:09 +0100
Subject: sched: Add struct rq::cpu_capacity_orig
This new field 'cpu_capacity_orig' reflects the original capacity of a CPU
before being altered by rt tasks and/or IRQ
The cpu_capacity_orig will be used:
- to detect when the capacity of a CPU has been noticeably reduced so we can
trig load balance to look for a CPU with better capacity. As an example, we
can detect when a CPU handles a significant amount of irq
(with CONFIG_IRQ_TIME_ACCOUNTING) but this CPU is seen as an idle CPU by
scheduler whereas CPUs, which are really idle, are available.
- evaluate the available capacity for CFS tasks
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Morten.Rasmussen@arm.com
Cc: dietmar.eggemann@arm.com
Cc: efault@gmx.de
Cc: linaro-kernel@lists.linaro.org
Cc: nicolas.pitre@linaro.org
Cc: preeti@linux.vnet.ibm.com
Cc: riel@redhat.com
Link: http://lkml.kernel.org/r/1425052454-25797-7-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/core.c | 2 +-
kernel/sched/fair.c | 8 +++++++-
kernel/sched/sched.h | 1 +
3 files changed, 9 insertions(+), 2 deletions(-)
(limited to 'kernel')
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index feda520bd034..7022e9084624 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7216,7 +7216,7 @@ void __init sched_init(void)
#ifdef CONFIG_SMP
rq->sd = NULL;
rq->rd = NULL;
- rq->cpu_capacity = SCHED_CAPACITY_SCALE;
+ rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
rq->post_schedule = 0;
rq->active_balance = 0;
rq->next_balance = jiffies;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index dc7c693f044a..10f84c3c6769 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4363,6 +4363,11 @@ static unsigned long capacity_of(int cpu)
return cpu_rq(cpu)->cpu_capacity;
}
+static unsigned long capacity_orig_of(int cpu)
+{
+ return cpu_rq(cpu)->cpu_capacity_orig;
+}
+
static unsigned long cpu_avg_load_per_task(int cpu)
{
struct rq *rq = cpu_rq(cpu);
@@ -6040,6 +6045,7 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu)
capacity >>= SCHED_CAPACITY_SHIFT;
+ cpu_rq(cpu)->cpu_capacity_orig = capacity;
sdg->sgc->capacity_orig = capacity;
capacity *= scale_rt_capacity(cpu);
@@ -6094,7 +6100,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
* Runtime updates will correct capacity_orig.
*/
if (unlikely(!rq->sd)) {
- capacity_orig += capacity_of(cpu);
+ capacity_orig += capacity_orig_of(cpu);
capacity += capacity_of(cpu);
continue;
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 36000029f33b..be56dfd645b2 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -615,6 +615,7 @@ struct rq {
struct sched_domain *sd;
unsigned long cpu_capacity;
+ unsigned long cpu_capacity_orig;
unsigned char idle_balance;
/* For active balancing */
--
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