linux-kernel - [PATCH v3 05/57] sched: Simplify get_nohz_timer

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Message-ID: <20230612093537.762718530@infradead.org>
Date:   Mon, 12 Jun 2023 11:07:18 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     torvalds@...ux-foundation.org, keescook@...omium.org,
        gregkh@...uxfoundation.org, pbonzini@...hat.com
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Subject: [PATCH v3 05/57] sched: Simplify get_nohz_timer_target()

Use guards to reduce gotos and simplify control flow.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/sched/core.c |   15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

--- 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;
 }
 
 /*