Commit a7c072ef authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

scftorture: Block scftorture_invoker() kthreads for offline CPUs 



Currently, CPU-hotplug operations might result in all but two
of (say) 100 CPUs being offline, which in turn might result in
false-positive diagnostics due to overload.  This commit therefore
causes scftorture_invoker() kthreads for offline CPUs to loop blocking
for 200 milliseconds at a time, thus continuously adjusting the number
of threads to match the number of online CPUs.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent de77d4da

kernel/scftorture.c

+12 −1
Original line number Diff line number Diff line
@@ -381,11 +381,14 @@ static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_ra 
// smp_call_function() family of functions.

static int scftorture_invoker(void *arg)

{

	int cpu;

	DEFINE_TORTURE_RANDOM(rand);

	struct scf_statistics *scfp = (struct scf_statistics *)arg;

	bool was_offline = false;



	VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu);

	set_cpus_allowed_ptr(current, cpumask_of(scfp->cpu % nr_cpu_ids));

	cpu = scfp->cpu % nr_cpu_ids;

	set_cpus_allowed_ptr(current, cpumask_of(cpu));

	set_user_nice(current, MAX_NICE);

	if (holdoff)

		schedule_timeout_interruptible(holdoff * HZ);
@@ -408,6 +411,14 @@ static int scftorture_invoker(void *arg) 


	do {

		scftorture_invoke_one(scfp, &rand);

		while (cpu_is_offline(cpu) && !torture_must_stop()) {

			schedule_timeout_interruptible(HZ / 5);

			was_offline = true;

		}

		if (was_offline) {

			set_cpus_allowed_ptr(current, cpumask_of(cpu));

			was_offline = false;

		}

	} while (!torture_must_stop());



	VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);

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