sched: Fix sched_domain iterations vs. RCU
Vladis Kletnieks reported a new RCU debug warning in the scheduler.
Since commit dce840a087
("sched: Dynamically allocate sched_domain/
sched_group data-structures") the sched_domain trees are protected by
RCU instead of RCU-sched.
This means that we need to include rcu_read_lock() protection when we
iterate them since disabling preemption doesn't suffice anymore.
Reported-by: Valdis.Kletnieks@vt.edu
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1302882741.2388.241.camel@twins
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
parent
2f36825b17
commit
057f3fadb3
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@ -1208,11 +1208,17 @@ int get_nohz_timer_target(void)
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int i;
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int i;
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struct sched_domain *sd;
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struct sched_domain *sd;
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rcu_read_lock();
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for_each_domain(cpu, sd) {
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for_each_domain(cpu, sd) {
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for_each_cpu(i, sched_domain_span(sd))
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for_each_cpu(i, sched_domain_span(sd)) {
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if (!idle_cpu(i))
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if (!idle_cpu(i)) {
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return i;
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cpu = i;
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goto unlock;
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}
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}
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}
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}
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unlock:
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rcu_read_unlock();
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return cpu;
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return cpu;
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}
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}
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/*
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/*
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@ -2415,12 +2421,14 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
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struct sched_domain *sd;
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struct sched_domain *sd;
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schedstat_inc(p, se.statistics.nr_wakeups_remote);
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schedstat_inc(p, se.statistics.nr_wakeups_remote);
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rcu_read_lock();
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for_each_domain(this_cpu, sd) {
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for_each_domain(this_cpu, sd) {
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if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
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if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
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schedstat_inc(sd, ttwu_wake_remote);
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schedstat_inc(sd, ttwu_wake_remote);
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break;
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break;
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}
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}
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}
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}
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rcu_read_unlock();
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}
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}
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#endif /* CONFIG_SMP */
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#endif /* CONFIG_SMP */
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