linux-kernel - [tip: sched/core] sched: Simplify get_nohz_timer

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Date:   Mon, 14 Aug 2023 15:08:07 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        "Joel Fernandes (Google)" <joel@...lfernandes.org>,
        Valentin Schneider <vschneid@...hat.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: sched/core] sched: Simplify get_nohz_timer_target()

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

Commit-ID:     7537b90c0036759e0b1b43dfbc6224dc5e900b13
Gitweb:        https://git.kernel.org/tip/7537b90c0036759e0b1b43dfbc6224dc5e900b13
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Tue, 01 Aug 2023 22:41:22 +02:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Mon, 14 Aug 2023 17:01:24 +02:00

sched: Simplify get_nohz_timer_target()

Use guards to reduce gotos and simplify control flow.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Joel Fernandes (Google) <joel@...lfernandes.org>
Reviewed-by: Valentin Schneider <vschneid@...hat.com>
Link: https://lore.kernel.org/r/20230801211811.828443100@infradead.org
---
 kernel/sched/core.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a97eab3..6cda296 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1097,25 +1097,22 @@ int get_nohz_timer_target(void)
 
 	hk_mask = housekeeping_cpumask(HK_TYPE_TIMER);
 
-	rcu_read_lock();
+	guard(rcu)();
+
 	for_each_domain(cpu, sd) {
 		for_each_cpu_and(i, sched_domain_span(sd), hk_mask) {
 			if (cpu == i)
 				continue;
 
-			if (!idle_cpu(i)) {
-				cpu = i;
-				goto unlock;
-			}
+			if (!idle_cpu(i))
+				return i;
 		}
 	}
 
 	if (default_cpu == -1)
 		default_cpu = housekeeping_any_cpu(HK_TYPE_TIMER);
-	cpu = default_cpu;
-unlock:
-	rcu_read_unlock();
-	return cpu;
+
+	return default_cpu;
 }
 
 /*