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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-09-10 18:18:47 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-09-15 16:01:06 +0200 |
| commit | 83f54960c11a14942ab00b54c51e91906b9d8235 (patch) | |
| tree | 6c7df778777568bb0c7375b4e7ec84ed532809df | |
| parent | sched: Weaken SD_POWERSAVINGS_BALANCE (diff) | |
| download | linux-83f54960c11a14942ab00b54c51e91906b9d8235.tar.xz linux-83f54960c11a14942ab00b54c51e91906b9d8235.zip | |
sched: for_each_domain() vs RCU
for_each_domain() uses RCU to serialize the sched_domains, except
it doesn't actually use rcu_read_lock() and instead relies on
disabling preemption -> FAIL.
XXX: audit other sched_domain code.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched_fair.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index eaa00014b499..43dc6d1d9e88 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1331,6 +1331,7 @@ static int select_task_rq_fair(struct task_struct *p, int flag, int sync) new_cpu = prev_cpu; } + rcu_read_lock(); for_each_domain(cpu, tmp) { /* * If power savings logic is enabled for a domain, see if we @@ -1369,8 +1370,10 @@ static int select_task_rq_fair(struct task_struct *p, int flag, int sync) if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { - if (wake_affine(tmp, p, sync)) - return cpu; + if (wake_affine(tmp, p, sync)) { + new_cpu = cpu; + goto out; + } want_affine = 0; } @@ -1416,6 +1419,8 @@ static int select_task_rq_fair(struct task_struct *p, int flag, int sync) /* while loop will break here if sd == NULL */ } +out: + rcu_read_unlock(); return new_cpu; } #endif /* CONFIG_SMP */ |