From ea14b57e8a181ac0561eba7a787e088f8c89f822 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 2 Feb 2018 10:27:00 +0100
Subject: [PATCH] sched/cpufreq: Provide migration hint
It was suggested that a migration hint might be usefull for the
CPU-freq governors.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched/cpufreq.h | 1 +
kernel/sched/fair.c | 31 +++++++++++++++++++------------
2 files changed, 20 insertions(+), 12 deletions(-)
diff --git a/include/linux/sched/cpufreq.h b/include/linux/sched/cpufreq.h
index b48f2fb3b316d..59667444669fc 100644
--- a/include/linux/sched/cpufreq.h
+++ b/include/linux/sched/cpufreq.h
@@ -9,6 +9,7 @@
*/
#define SCHED_CPUFREQ_IOWAIT (1U << 0)
+#define SCHED_CPUFREQ_MIGRATION (1U << 1)
#ifdef CONFIG_CPU_FREQ
struct update_util_data {
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 494d5db9a6cdf..e8f5efe2936c7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -772,7 +772,7 @@ void post_init_entity_util_avg(struct sched_entity *se)
* For !fair tasks do:
*
update_cfs_rq_load_avg(now, cfs_rq);
- attach_entity_load_avg(cfs_rq, se);
+ attach_entity_load_avg(cfs_rq, se, 0);
switched_from_fair(rq, p);
*
* such that the next switched_to_fair() has the
@@ -3009,11 +3009,11 @@ static inline void update_cfs_group(struct sched_entity *se)
}
#endif /* CONFIG_FAIR_GROUP_SCHED */
-static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
+static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags)
{
struct rq *rq = rq_of(cfs_rq);
- if (&rq->cfs == cfs_rq) {
+ if (&rq->cfs == cfs_rq || (flags & SCHED_CPUFREQ_MIGRATION)) {
/*
* There are a few boundary cases this might miss but it should
* get called often enough that that should (hopefully) not be
@@ -3028,7 +3028,7 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
*
* See cpu_util().
*/
- cpufreq_update_util(rq, 0);
+ cpufreq_update_util(rq, flags);
}
}
@@ -3686,7 +3686,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
#endif
if (decayed)
- cfs_rq_util_change(cfs_rq);
+ cfs_rq_util_change(cfs_rq, 0);
return decayed;
}
@@ -3699,7 +3699,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
* Must call update_cfs_rq_load_avg() before this, since we rely on
* cfs_rq->avg.last_update_time being current.
*/
-static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib;
@@ -3735,7 +3735,7 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
add_tg_cfs_propagate(cfs_rq, se->avg.load_sum);
- cfs_rq_util_change(cfs_rq);
+ cfs_rq_util_change(cfs_rq, flags);
}
/**
@@ -3754,7 +3754,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum);
- cfs_rq_util_change(cfs_rq);
+ cfs_rq_util_change(cfs_rq, 0);
}
/*
@@ -3784,7 +3784,14 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
if (!se->avg.last_update_time && (flags & DO_ATTACH)) {
- attach_entity_load_avg(cfs_rq, se);
+ /*
+ * DO_ATTACH means we're here from enqueue_entity().
+ * !last_update_time means we've passed through
+ * migrate_task_rq_fair() indicating we migrated.
+ *
+ * IOW we're enqueueing a task on a new CPU.
+ */
+ attach_entity_load_avg(cfs_rq, se, SCHED_CPUFREQ_MIGRATION);
update_tg_load_avg(cfs_rq, 0);
} else if (decayed && (flags & UPDATE_TG))
@@ -3880,13 +3887,13 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1)
{
- cfs_rq_util_change(cfs_rq);
+ cfs_rq_util_change(cfs_rq, 0);
}
static inline void remove_entity_load_avg(struct sched_entity *se) {}
static inline void
-attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) {}
static inline void
detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
@@ -9726,7 +9733,7 @@ static void attach_entity_cfs_rq(struct sched_entity *se)
/* Synchronize entity with its cfs_rq */
update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD);
- attach_entity_load_avg(cfs_rq, se);
+ attach_entity_load_avg(cfs_rq, se, 0);
update_tg_load_avg(cfs_rq, false);
propagate_entity_cfs_rq(se);
}
--
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