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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-04-18 11:24:34 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-04-19 10:56:54 +0200 |
| commit | 057f3fadb347e9c51b07e1b277bbdda79f976768 (patch) | |
| tree | 12f637ad30129245ef51836df1d134257d827dd5 /kernel/sched.c | |
| parent | 2f36825b176f67e5c5228aa33d828bc39718811f (diff) | |
| download | linux-057f3fadb347e9c51b07e1b277bbdda79f976768.tar.gz linux-057f3fadb347e9c51b07e1b277bbdda79f976768.tar.bz2 linux-057f3fadb347e9c51b07e1b277bbdda79f976768.zip | |
sched: Fix sched_domain iterations vs. RCU
Vladis Kletnieks reported a new RCU debug warning in the scheduler.
Since commit dce840a08702b ("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>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 0cfe0310ed5d..27d3e73a2af6 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -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 */ |