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| author | Dmitry Adamushko <dmitry.adamushko@gmail.com> | 2008-05-12 21:21:15 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-06-06 15:19:30 +0200 |
| commit | d07355f5def74d060333563b36ab51b89fd44cdd (patch) | |
| tree | e39af1fccaaa98b7ae4cc80628e8a8b69f73ebc1 /kernel/sched.c | |
| parent | 6d299f1b53b84e2665f402d9bcc494800aba6386 (diff) | |
| download | lwn-d07355f5def74d060333563b36ab51b89fd44cdd.tar.gz lwn-d07355f5def74d060333563b36ab51b89fd44cdd.zip | |
sched: check for SD_SERIALIZE atomically in rebalance_domains()
Nothing really serious here, mainly just a matter of nit-picking :-/
From: Dmitry Adamushko <dmitry.adamushko@gmail.com>
For CONFIG_SCHED_DEBUG && CONFIG_SYSCT configs, sd->flags can be altered
while being manipulated in rebalance_domains(). Let's do an atomic check.
We rely here on the atomicity of read/write accesses for aligned words.
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 8a1257b65560..90329f1f8941 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3668,6 +3668,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) /* Earliest time when we have to do rebalance again */ unsigned long next_balance = jiffies + 60*HZ; int update_next_balance = 0; + int need_serialize; cpumask_t tmp; for_each_domain(cpu, sd) { @@ -3685,8 +3686,9 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) if (interval > HZ*NR_CPUS/10) interval = HZ*NR_CPUS/10; + need_serialize = sd->flags & SD_SERIALIZE; - if (sd->flags & SD_SERIALIZE) { + if (need_serialize) { if (!spin_trylock(&balancing)) goto out; } @@ -3702,7 +3704,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) } sd->last_balance = jiffies; } - if (sd->flags & SD_SERIALIZE) + if (need_serialize) spin_unlock(&balancing); out: if (time_after(next_balance, sd->last_balance + interval)) { |