Commit 024c9d2f authored Oct 09, 2017 by Peter Zijlstra Committed by Ingo Molnar Oct 10, 2017

sched/core: Ensure load_balance() respects the active_mask

While load_balance() masks the source CPUs against active_mask, it had
a hole against the destination CPU. Ensure the destination CPU is also
part of the 'domain-mask & active-mask' set.

Reported-by: Levin, Alexander (Sasha Levin) <alexander.levin@verizon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 77d1dfda ("sched/topology, cpuset: Avoid spurious/wrong domain rebuilds")
Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent f2cdd9cc

kernel/sched/fair.c

+7 −0

Original line number	Original line	Diff line number	Diff line
	@@ -8042,6 +8042,13 @@ static int should_we_balance(struct lb_env *env)
	struct sched_group *sg = env->sd->groups;		struct sched_group *sg = env->sd->groups;
	int cpu, balance_cpu = -1;		int cpu, balance_cpu = -1;

			/*
			* Ensure the balancing environment is consistent; can happen
			* when the softirq triggers 'during' hotplug.
			*/
			if (!cpumask_test_cpu(env->dst_cpu, env->cpus))
			return 0;

	/*		/*
	* In the newly idle case, we will allow all the cpu's		* In the newly idle case, we will allow all the cpu's
	* to do the newly idle load balance.		* to do the newly idle load balance.