attach_entity_load_avg() is called (indirectly) from:
- switched_to_fair(): switch between classes to fair
- task_move_group_fair(): move between task groups
- enqueue_entity_load_avg(): enqueue entity
Only in switched_to_fair() is it possible that the task's last_update_time
is not 0 and therefore the task needs sched avgs update, so move the task
sched avgs update to switched_to_fair() only. In addition, the code is
refactored and code comments are updated.
No functionality change.
Signed-off-by: Yuyang Du <yuyang...@intel.com>
---
kernel/sched/fair.c | 43 ++++++++++++++++++++-----------------------
1 file changed, 20 insertions(+), 23 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c6dd8ba..34e658b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2935,24 +2935,6 @@ static inline void update_load_avg(struct sched_entity
*se, int update_tg)
static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity
*se)
{
- if (!sched_feat(ATTACH_AGE_LOAD))
- goto skip_aging;
-
- /*
- * If we got migrated (either between CPUs or between cgroups) we'll
- * have aged the average right before clearing @last_update_time.
- */
- if (se->avg.last_update_time) {
- __update_load_avg(cfs_rq->avg.last_update_time,
cpu_of(rq_of(cfs_rq)),
- &se->avg, 0, 0, NULL);
-
- /*
- * XXX: we could have just aged the entire load away if we've
been
- * absent from the fair class for too long.
- */
- }
-
-skip_aging:
se->avg.last_update_time = cfs_rq->avg.last_update_time;
cfs_rq->avg.load_avg += se->avg.load_avg;
cfs_rq->avg.load_sum += se->avg.load_sum;
@@ -2962,6 +2944,19 @@ skip_aging:
cfs_rq_util_change(cfs_rq);
}
+static inline void attach_age_load_task(struct rq *rq, struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+
+ if (!sched_feat(ATTACH_AGE_LOAD))
+ return;
+
+ if (se->avg.last_update_time) {
+ __update_load_avg(cfs_rq_of(se)->avg.last_update_time,
cpu_of(rq),
+ &se->avg, 0, 0, NULL);
+ }
+}
+
static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity
*se)
{
__update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)),
@@ -3091,6 +3086,7 @@ static inline void
attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
static inline void
detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+static inline void attach_age_load_task(struct rq *rq, struct task_struct *p)
{}
static inline int idle_balance(struct rq *rq)
{
@@ -8390,6 +8386,12 @@ static void switched_from_fair(struct rq *rq, struct
task_struct *p)
static void switched_to_fair(struct rq *rq, struct task_struct *p)
{
+ /*
+ * If we change between classes, age the averages before attaching them.
+ * XXX: we could have just aged the entire load away if we've been
+ * absent from the fair class for too long.
+ */
+ attach_age_load_task(rq, p);
attach_task_cfs_rq(p);
if (task_on_rq_queued(p)) {
@@ -8441,11 +8443,6 @@ static void task_move_group_fair(struct task_struct *p)
{
detach_task_cfs_rq(p);
set_task_rq(p, task_cpu(p));
-
-#ifdef CONFIG_SMP
- /* Tell se's cfs_rq has been changed -- migrated */
- p->se.avg.last_update_time = 0;
-#endif
attach_task_cfs_rq(p);
}
--
1.7.9.5
