rcu: Add more tracing of expedited grace periods (9a414201) · Commits · 戴 / test

include/trace/events/rcu.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -179,6 +179,9 @@ TRACE_EVENT(rcu_grace_period_init,
		*
		* "snap": Captured snapshot of expedited grace period sequence number.
		* "start": Started a real expedited grace period.
		* "reset": Started resetting the tree
		* "select": Started selecting the CPUs to wait on.
		* "startwait": Started waiting on selected CPUs.
		* "end": Ended a real expedited grace period.
		* "endwake": Woke piggybackers up.
		* "done": Someone else did the expedited grace period for us.

+7 −1

Original line number	Diff line number	Diff line
		@@ -77,12 +77,18 @@ static inline void rcu_seq_start(unsigned long *sp)
		WARN_ON_ONCE(rcu_seq_state(*sp) != 1);
		}

		/* Compute the end-of-grace-period value for the specified sequence number. */
		static inline unsigned long rcu_seq_endval(unsigned long *sp)
		{
		return (*sp \| RCU_SEQ_STATE_MASK) + 1;
		}

		/* Adjust sequence number for end of update-side operation. */
		static inline void rcu_seq_end(unsigned long *sp)
		{
		smp_mb(); /* Ensure update-side operation before counter increment. */
		WARN_ON_ONCE(!rcu_seq_state(*sp));
		WRITE_ONCE(sp, (sp \| RCU_SEQ_STATE_MASK) + 1);
		WRITE_ONCE(*sp, rcu_seq_endval(sp));
		}

		/* Take a snapshot of the update side's sequence number. */

+12 −0

Original line number	Diff line number	Diff line
		@@ -28,6 +28,15 @@ static void rcu_exp_gp_seq_start(struct rcu_state *rsp)
		rcu_seq_start(&rsp->expedited_sequence);
		}

		/*
		* Return then value that expedited-grace-period counter will have
		* at the end of the current grace period.
		*/
		static unsigned long rcu_exp_gp_seq_endval(struct rcu_state *rsp)
		{
		return rcu_seq_endval(&rsp->expedited_sequence);
		}

		/*
		* Record the end of an expedited grace period.
		*/
		@@ -366,7 +375,9 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
		int ret;
		struct rcu_node *rnp;

		trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("reset"));
		sync_exp_reset_tree(rsp);
		trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("select"));
		rcu_for_each_leaf_node(rsp, rnp) {
		raw_spin_lock_irqsave_rcu_node(rnp, flags);

		@@ -443,6 +454,7 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
		struct rcu_node *rnp_root = rcu_get_root(rsp);
		int ret;

		trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("startwait"));
		jiffies_stall = rcu_jiffies_till_stall_check();
		jiffies_start = jiffies;