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Commit 09c7b890 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Paul E. McKenney
Browse files

rcu: Add event tracing for no-CBs CPUs' grace periods 



Signed-off-by: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 21e7a608

include/trace/events/rcu.h

+55 −0
Original line number Diff line number Diff line
@@ -71,6 +71,58 @@ TRACE_EVENT(rcu_grace_period, 
		  __entry->rcuname, __entry->gpnum, __entry->gpevent)

);



/*

 * Tracepoint for no-callbacks grace-period events.  The caller should

 * pull the data from the rcu_node structure, other than rcuname, which

 * comes from the rcu_state structure, and event, which is one of the

 * following:

 *

 * "Startleaf": Request a nocb grace period based on leaf-node data.

 * "Startedleaf": Leaf-node start proved sufficient.

 * "Startedleafroot": Leaf-node start proved sufficient after checking root.

 * "Startedroot": Requested a nocb grace period based on root-node data.

 * "StartWait": Start waiting for the requested grace period.

 * "ResumeWait": Resume waiting after signal.

 * "EndWait": Complete wait.

 * "Cleanup": Clean up rcu_node structure after previous GP.

 * "CleanupMore": Clean up, and another no-CB GP is needed.

 */

TRACE_EVENT(rcu_nocb_grace_period,



	TP_PROTO(char *rcuname, unsigned long gpnum, unsigned long completed,

		 unsigned long c, u8 level, int grplo, int grphi,

		 char *gpevent),



	TP_ARGS(rcuname, gpnum, completed, c, level, grplo, grphi, gpevent),



	TP_STRUCT__entry(

		__field(char *, rcuname)

		__field(unsigned long, gpnum)

		__field(unsigned long, completed)

		__field(unsigned long, c)

		__field(u8, level)

		__field(int, grplo)

		__field(int, grphi)

		__field(char *, gpevent)

	),



	TP_fast_assign(

		__entry->rcuname = rcuname;

		__entry->gpnum = gpnum;

		__entry->completed = completed;

		__entry->c = c;

		__entry->level = level;

		__entry->grplo = grplo;

		__entry->grphi = grphi;

		__entry->gpevent = gpevent;

	),



	TP_printk("%s %lu %lu %lu %u %d %d %s",

		  __entry->rcuname, __entry->gpnum, __entry->completed,

		  __entry->c, __entry->level, __entry->grplo, __entry->grphi,

		  __entry->gpevent)

);



/*

 * Tracepoint for grace-period-initialization events.  These are

 * distinguished by the type of RCU, the new grace-period number, the
@@ -601,6 +653,9 @@ TRACE_EVENT(rcu_barrier, 
#define trace_rcu_grace_period(rcuname, gpnum, gpevent) do { } while (0)

#define trace_rcu_grace_period_init(rcuname, gpnum, level, grplo, grphi, \

				    qsmask) do { } while (0)

#define trace_rcu_nocb_grace_period(rcuname, gpnum, completed, c, \

				    level, grplo, grphi, event) \

				    do { } while (0)

#define trace_rcu_preempt_task(rcuname, pid, gpnum) do { } while (0)

#define trace_rcu_unlock_preempted_task(rcuname, gpnum, pid) do { } while (0)

#define trace_rcu_quiescent_state_report(rcuname, gpnum, mask, qsmask, level, \

kernel/rcutree_plugin.h

+30 −0
Original line number Diff line number Diff line
@@ -2201,6 +2201,9 @@ static int rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp) 
	wake_up_all(&rnp->nocb_gp_wq[c & 0x1]);

	rnp->n_nocb_gp_requests[c & 0x1] = 0;

	needmore = rnp->n_nocb_gp_requests[(c + 1) & 0x1];

	trace_rcu_nocb_grace_period(rsp->name, rnp->gpnum, rnp->completed,

				    c, rnp->level, rnp->grplo, rnp->grphi,

				    needmore ? "CleanupMore" : "Cleanup");

	return needmore;

}
@@ -2347,6 +2350,9 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) 


	/* Count our request for a grace period. */

	rnp->n_nocb_gp_requests[c & 0x1]++;

	trace_rcu_nocb_grace_period(rdp->rsp->name, rnp->gpnum, rnp->completed,

				    c, rnp->level, rnp->grplo, rnp->grphi,

				    "Startleaf");



	if (rnp->gpnum != rnp->completed) {
@@ -2355,6 +2361,10 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) 
		 * is in progress, so we are done.  When this grace

		 * period ends, our request will be acted upon.

		 */

		trace_rcu_nocb_grace_period(rdp->rsp->name,

					    rnp->gpnum, rnp->completed, c,

					    rnp->level, rnp->grplo, rnp->grphi,

					    "Startedleaf");

		raw_spin_unlock_irqrestore(&rnp->lock, flags);



	} else {
@@ -2366,6 +2376,11 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) 
		if (rnp != rnp_root)

			raw_spin_lock(&rnp_root->lock); /* irqs disabled. */

		if (rnp_root->gpnum != rnp_root->completed) {

			trace_rcu_nocb_grace_period(rdp->rsp->name,

						    rnp->gpnum, rnp->completed,

						    c, rnp->level,

						    rnp->grplo, rnp->grphi,

						    "Startedleafroot");

			raw_spin_unlock(&rnp_root->lock); /* irqs disabled. */

		} else {
@@ -2381,6 +2396,11 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) 
			c = rnp_root->completed + 1;

			rnp->n_nocb_gp_requests[c & 0x1]++;

			rnp_root->n_nocb_gp_requests[c & 0x1]++;

			trace_rcu_nocb_grace_period(rdp->rsp->name,

						    rnp->gpnum, rnp->completed,

						    c, rnp->level,

						    rnp->grplo, rnp->grphi,

						    "Startedroot");

			local_save_flags(flags1);

			rcu_start_gp(rdp->rsp, flags1); /* Rlses ->lock. */

		}
@@ -2396,6 +2416,9 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) 
	 * Wait for the grace period.  Do so interruptibly to avoid messing

	 * up the load average.

	 */

	trace_rcu_nocb_grace_period(rdp->rsp->name, rnp->gpnum, rnp->completed,

				    c, rnp->level, rnp->grplo, rnp->grphi,

				    "StartWait");

	for (;;) {

		wait_event_interruptible(

			rnp->nocb_gp_wq[c & 0x1],
@@ -2403,7 +2426,14 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) 
		if (likely(d))

			break;

		flush_signals(current);

	}

		trace_rcu_nocb_grace_period(rdp->rsp->name,

					    rnp->gpnum, rnp->completed, c,

					    rnp->level, rnp->grplo, rnp->grphi,

					    "ResumeWait");

	}

	trace_rcu_nocb_grace_period(rdp->rsp->name, rnp->gpnum, rnp->completed,

				    c, rnp->level, rnp->grplo, rnp->grphi,

				    "EndWait");

	smp_mb(); /* Ensure that CB invocation happens after GP end. */

}