linux-kernel - [PATCH v5 12/19] sched: Unnest ttwu_runnable in prep for proxy-execution

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Message-ID: <20230819060915.3001568-13-jstultz@google.com>
Date:   Sat, 19 Aug 2023 06:08:46 +0000
From:   John Stultz <jstultz@...gle.com>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     John Stultz <jstultz@...gle.com>,
        Joel Fernandes <joelaf@...gle.com>,
        Qais Yousef <qyousef@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Valentin Schneider <vschneid@...hat.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>,
        Zimuzo Ezeozue <zezeozue@...gle.com>,
        Youssef Esmat <youssefesmat@...gle.com>,
        Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Will Deacon <will@...nel.org>,
        Waiman Long <longman@...hat.com>,
        Boqun Feng <boqun.feng@...il.com>,
        "Paul E . McKenney" <paulmck@...nel.org>, kernel-team@...roid.com
Subject: [PATCH v5 12/19] sched: Unnest ttwu_runnable in prep for proxy-execution

Slightly rework ttwu_runnable to minimize the nesting to help
make the proxy-execution changes easier to read.

Should be no logical change here.

Cc: Joel Fernandes <joelaf@...gle.com>
Cc: Qais Yousef <qyousef@...gle.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Juri Lelli <juri.lelli@...hat.com>
Cc: Vincent Guittot <vincent.guittot@...aro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@....com>
Cc: Valentin Schneider <vschneid@...hat.com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Ben Segall <bsegall@...gle.com>
Cc: Zimuzo Ezeozue <zezeozue@...gle.com>
Cc: Youssef Esmat <youssefesmat@...gle.com>
Cc: Mel Gorman <mgorman@...e.de>
Cc: Daniel Bristot de Oliveira <bristot@...hat.com>
Cc: Will Deacon <will@...nel.org>
Cc: Waiman Long <longman@...hat.com>
Cc: Boqun Feng <boqun.feng@...il.com>
Cc: "Paul E . McKenney" <paulmck@...nel.org>
Cc: kernel-team@...roid.com
Signed-off-by: John Stultz <jstultz@...gle.com>
---
 kernel/sched/core.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ea0a7fb144fd..2d957a14104a 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3840,18 +3840,20 @@ static int ttwu_runnable(struct task_struct *p, int wake_flags)
 	int ret = 0;
 
 	rq = __task_rq_lock(p, &rf);
-	if (task_on_rq_queued(p)) {
-		if (!task_on_cpu(rq, p)) {
-			/*
-			 * When on_rq && !on_cpu the task is preempted, see if
-			 * it should preempt the task that is current now.
-			 */
-			update_rq_clock(rq);
-			check_preempt_curr(rq, p, wake_flags);
-		}
-		ttwu_do_wakeup(p);
-		ret = 1;
+	if (!task_on_rq_queued(p))
+		goto out_unlock;
+
+	if (!task_on_cpu(rq, p)) {
+		/*
+		 * When on_rq && !on_cpu the task is preempted, see if
+		 * it should preempt the task that is current now.
+		 */
+		update_rq_clock(rq);
+		check_preempt_curr(rq, p, wake_flags);
 	}
+	ttwu_do_wakeup(p);
+	ret = 1;
+out_unlock:
 	__task_rq_unlock(rq, &rf);
 
 	return ret;
-- 
2.42.0.rc1.204.g551eb34607-goog