dect
/
linux-2.6
Archived
13
0
Fork 0
Code Releases Activity

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:
Peter Zijlstra 2011-04-18 11:24:34 +02:00 committed by Ingo Molnar
parent 2f36825b17
commit 057f3fadb3
1 changed files with 11 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
kernel/sched.c
View File

@ -1208,11 +1208,17 @@ int get_nohz_timer_target(void)
int i;
struct sched_domain *sd;
rcu_read_lock();
for_each_domain(cpu, sd) {
for_each_cpu(i, sched_domain_span(sd))
if (!idle_cpu(i))
return i;
for_each_cpu(i, sched_domain_span(sd)) {
if (!idle_cpu(i)) {
cpu = i;
goto unlock;
}
}
}
unlock:
rcu_read_unlock();
return cpu;
}
/*
@ -2415,12 +2421,14 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
struct sched_domain *sd;
schedstat_inc(p, se.statistics.nr_wakeups_remote);
rcu_read_lock();
for_each_domain(this_cpu, sd) {
if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
schedstat_inc(sd, ttwu_wake_remote);
break;
}
}
rcu_read_unlock();
}
#endif /* CONFIG_SMP */