sched: check for SD_SERIALIZE atomically in rebalance_domains() (d07355f5) · Commits · 戴 / test

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>

kernel/sched.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -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)) {

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