Commit 7e0669c3 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu-tasks: Add IPI failure count to statistics 



This commit adds a failure-return count for smp_call_function_single(),
and adds this to the console messages for rcutorture writer stalls and at
the end of rcutorture testing.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 039f3cc9

kernel/rcu/tasks.h

+7 −4
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ typedef void (*postgp_func_t)(struct rcu_tasks *rtp); 
 * @gp_start: Most recent grace-period start in jiffies.

 * @n_gps: Number of grace periods completed since boot.

 * @n_ipis: Number of IPIs sent to encourage grace periods to end.

 * @n_ipis_fails: Number of IPI-send failures.

 * @pregp_func: This flavor's pre-grace-period function (optional).

 * @pertask_func: This flavor's per-task scan function (optional).

 * @postscan_func: This flavor's post-task scan function (optional).
@@ -51,6 +52,7 @@ struct rcu_tasks { 
	unsigned long gp_start;

	unsigned long n_gps;

	unsigned long n_ipis;

	unsigned long n_ipis_fails;

	struct task_struct *kthread_ptr;

	rcu_tasks_gp_func_t gp_func;

	pregp_func_t pregp_func;
@@ -290,12 +292,12 @@ static void __init rcu_tasks_bootup_oddness(void) 
/* Dump out rcutorture-relevant state common to all RCU-tasks flavors. */

static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)

{

	pr_info("%s: %s(%d) since %lu g:%lu i:%lu %c%c %s\n",

	pr_info("%s: %s(%d) since %lu g:%lu i:%lu/%lu %c%c %s\n",

		rtp->kname,

		tasks_gp_state_getname(rtp),

		data_race(rtp->gp_state),

		tasks_gp_state_getname(rtp), data_race(rtp->gp_state),

		jiffies - data_race(rtp->gp_jiffies),

		data_race(rtp->n_gps), data_race(rtp->n_ipis),

		data_race(rtp->n_gps),

		data_race(rtp->n_ipis_fails), data_race(rtp->n_ipis),

		".k"[!!data_race(rtp->kthread_ptr)],

		".C"[!!data_race(rtp->cbs_head)],

		s);
@@ -909,6 +911,7 @@ static void trc_wait_for_one_reader(struct task_struct *t, 
					     trc_read_check_handler, t, 0)) {

			// Just in case there is some other reason for

			// failure than the target CPU being offline.

			rcu_tasks_trace.n_ipis_fails++;

			per_cpu(trc_ipi_to_cpu, cpu) = false;

			t->trc_ipi_to_cpu = cpu;

			if (atomic_dec_and_test(&trc_n_readers_need_end)) {