Commit a59ee765 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

torture: Forgive -EBUSY from boottime CPU-hotplug operations 



During boot, CPU hotplug is often disabled, for example by PCI probing.
On large systems that take substantial time to boot, this can result
in spurious RCU_HOTPLUG errors.  This commit therefore forgives any
boottime -EBUSY CPU-hotplug failures by adjusting counters to pretend
that the corresponding attempt never happened.  A non-splat record
of the failed attempt is emitted to the console with the added string
"(-EBUSY forgiven during boot)".

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 43550809

kernel/torture.c

+18 −4
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes, 
{

	unsigned long delta;

	int ret;

	char *s;

	unsigned long starttime;



	if (!cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
@@ -99,10 +100,16 @@ bool torture_offline(int cpu, long *n_offl_attempts, long *n_offl_successes, 
	(*n_offl_attempts)++;

	ret = cpu_down(cpu);

	if (ret) {

		s = "";

		if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {

			// PCI probe frequently disables hotplug during boot.

			(*n_offl_attempts)--;

			s = " (-EBUSY forgiven during boot)";

		}

		if (verbose)

			pr_alert("%s" TORTURE_FLAG

				 "torture_onoff task: offline %d failed: errno %d\n",

				 torture_type, cpu, ret);

				 "torture_onoff task: offline %d failed%s: errno %d\n",

				 torture_type, cpu, s, ret);

	} else {

		if (verbose > 1)

			pr_alert("%s" TORTURE_FLAG
@@ -137,6 +144,7 @@ bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes, 
{

	unsigned long delta;

	int ret;

	char *s;

	unsigned long starttime;



	if (cpu_online(cpu) || !cpu_is_hotpluggable(cpu))
@@ -150,10 +158,16 @@ bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes, 
	(*n_onl_attempts)++;

	ret = cpu_up(cpu);

	if (ret) {

		s = "";

		if (!rcu_inkernel_boot_has_ended() && ret == -EBUSY) {

			// PCI probe frequently disables hotplug during boot.

			(*n_onl_attempts)--;

			s = " (-EBUSY forgiven during boot)";

		}

		if (verbose)

			pr_alert("%s" TORTURE_FLAG

				 "torture_onoff task: online %d failed: errno %d\n",

				 torture_type, cpu, ret);

				 "torture_onoff task: online %d failed%s: errno %d\n",

				 torture_type, cpu, s, ret);

	} else {

		if (verbose > 1)

			pr_alert("%s" TORTURE_FLAG