[PATCH v3 05/57] sched: Simplify get_nohz_timer_target()

From: Peter Zijlstra
Date: Mon Jun 12 2023 - 05:56:34 EST


Use guards to reduce gotos and simplify control flow.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
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;
}

/*