[tip: sched/core] sched,stats: Further simplify sched_info

From: tip-bot2 for Peter Zijlstra
Date: Wed May 19 2021 - 04:09:25 EST


The following commit has been merged into the sched/core branch of tip:

Commit-ID: 90a0ff4ec9c65cae3085d23301933172cea3f38a
Gitweb: https://git.kernel.org/tip/90a0ff4ec9c65cae3085d23301933172cea3f38a
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 12 May 2021 13:32:37 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 18 May 2021 12:53:53 +02:00

sched,stats: Further simplify sched_info

There's no point doing delta==0 updates.

Suggested-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
kernel/sched/stats.h | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 33ffd41..111072e 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -160,10 +160,11 @@ static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t)
{
unsigned long long delta = 0;

- if (t->sched_info.last_queued) {
- delta = rq_clock(rq) - t->sched_info.last_queued;
- t->sched_info.last_queued = 0;
- }
+ if (!t->sched_info.last_queued)
+ return;
+
+ delta = rq_clock(rq) - t->sched_info.last_queued;
+ t->sched_info.last_queued = 0;
t->sched_info.run_delay += delta;

rq_sched_info_dequeue(rq, delta);
@@ -176,12 +177,14 @@ static inline void sched_info_dequeue(struct rq *rq, struct task_struct *t)
*/
static void sched_info_arrive(struct rq *rq, struct task_struct *t)
{
- unsigned long long now = rq_clock(rq), delta = 0;
+ unsigned long long now, delta = 0;

- if (t->sched_info.last_queued) {
- delta = now - t->sched_info.last_queued;
- t->sched_info.last_queued = 0;
- }
+ if (!t->sched_info.last_queued)
+ return;
+
+ now = rq_clock(rq);
+ delta = now - t->sched_info.last_queued;
+ t->sched_info.last_queued = 0;
t->sched_info.run_delay += delta;
t->sched_info.last_arrival = now;
t->sched_info.pcount++;