linux-kernel - [PATCH 13/14] sched,fair: flatten update

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Message-Id: <20190722173348.9241-14-riel@surriel.com>
Date:   Mon, 22 Jul 2019 13:33:47 -0400
From:   Rik van Riel <riel@...riel.com>
To:     linux-kernel@...r.kernel.org
Cc:     kernel-team@...com, pjt@...gle.com, dietmar.eggemann@....com,
        peterz@...radead.org, mingo@...hat.com, morten.rasmussen@....com,
        tglx@...utronix.de, mgorman@...hsingularity.net,
        vincent.guittot@...aro.org, Rik van Riel <riel@...riel.com>
Subject: [PATCH 13/14] sched,fair: flatten update_curr functionality

Make it clear that update_curr only works on tasks any more.

There is no need for task_tick_fair to call it on every sched entity up
the hierarchy, so move the call out of entity_tick.

Signed-off-by: Rik van Riel <riel@...riel.com>`

Header from folded patch 'fix-attach-detach_enticy_cfs_rq.patch':

Subject: sched,fair: fix attach/detach_entity_cfs_rq

While attach_entity_cfs_rq and detach_entity_cfs_rq should iterate over
the hierarchy, they do not need to so that twice.

Passing flags into propagate_entity_cfs_rq allows us to reuse that same
loop from other functions.

Signed-off-by: Rik van Riel <riel@...riel.com>
---
 kernel/sched/fair.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 224cd9b20887..4c7e1818efba 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -872,10 +872,11 @@ static void update_tg_load_avg(struct cfs_rq *cfs_rq, int force)
 static void update_curr(struct cfs_rq *cfs_rq)
 {
 	struct sched_entity *curr = cfs_rq->curr;
+	struct task_struct *curtask;
 	u64 now = rq_clock_task(rq_of(cfs_rq));
 	u64 delta_exec;
 
-	if (unlikely(!curr))
+	if (unlikely(!curr) || !entity_is_task(curr))
 		return;
 
 	delta_exec = now - curr->exec_start;
@@ -893,13 +894,10 @@ static void update_curr(struct cfs_rq *cfs_rq)
 	curr->vruntime += calc_delta_fair(delta_exec, curr);
 	update_min_vruntime(cfs_rq);
 
-	if (entity_is_task(curr)) {
-		struct task_struct *curtask = task_of(curr);
-
-		trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
-		cgroup_account_cputime(curtask, delta_exec);
-		account_group_exec_runtime(curtask, delta_exec);
-	}
+	curtask = task_of(curr);
+	trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime);
+	cgroup_account_cputime(curtask, delta_exec);
+	account_group_exec_runtime(curtask, delta_exec);
 
 	account_cfs_rq_runtime(cfs_rq, delta_exec);
 }
@@ -4192,11 +4190,6 @@ static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev)
 static void
 entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
 {
-	/*
-	 * Update run-time statistics of the 'current'.
-	 */
-	update_curr(cfs_rq);
-
 	/*
 	 * Ensure that runnable average is periodically updated.
 	 */
@@ -10025,6 +10018,11 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
 	struct cfs_rq *cfs_rq;
 	struct sched_entity *se = &curr->se;
 
+	/*
+	 * Update run-time statistics of the 'current'.
+	 */
+	update_curr(&rq->cfs);
+
 	for_each_sched_entity(se) {
 		cfs_rq = group_cfs_rq_of_parent(se);
 		entity_tick(cfs_rq, se, queued);
-- 
2.20.1