Commit e816d56f authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Add callbacks-invoked counters 



This commit adds a count of the callbacks invoked to the per-CPU rcu_data
structure.  This count is printed by the show_rcu_gp_kthreads() that
is invoked by rcutorture and the RCU CPU stall-warning code.  It is also
intended for use by drgn.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent abfce041

kernel/rcu/tree.c

+1 −0
Original line number Diff line number Diff line
@@ -2443,6 +2443,7 @@ static void rcu_do_batch(struct rcu_data *rdp) 
	local_irq_save(flags);

	rcu_nocb_lock(rdp);

	count = -rcl.len;

	rdp->n_cbs_invoked += count;

	trace_rcu_batch_end(rcu_state.name, count, !!rcl.head, need_resched(),

			    is_idle_task(current), rcu_is_callbacks_kthread());

kernel/rcu/tree.h

+1 −0
Original line number Diff line number Diff line
@@ -171,6 +171,7 @@ struct rcu_data { 
					/* different grace periods. */

	long		qlen_last_fqs_check;

					/* qlen at last check for QS forcing */

	unsigned long	n_cbs_invoked;	/* # callbacks invoked since boot. */

	unsigned long	n_force_qs_snap;

					/* did other CPU force QS recently? */

	long		blimit;		/* Upper limit on a processed batch */

kernel/rcu/tree_stall.h

+3 −0
Original line number Diff line number Diff line
@@ -649,6 +649,7 @@ static void check_cpu_stall(struct rcu_data *rdp) 
 */

void show_rcu_gp_kthreads(void)

{

	unsigned long cbs = 0;

	int cpu;

	unsigned long j;

	unsigned long ja;
@@ -690,9 +691,11 @@ void show_rcu_gp_kthreads(void) 
	}

	for_each_possible_cpu(cpu) {

		rdp = per_cpu_ptr(&rcu_data, cpu);

		cbs += data_race(rdp->n_cbs_invoked);

		if (rcu_segcblist_is_offloaded(&rdp->cblist))

			show_rcu_nocb_state(rdp);

	}

	pr_info("RCU callbacks invoked since boot: %lu\n", cbs);

	show_rcu_tasks_gp_kthreads();

}

EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads);

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