Commit e3771c85 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Paul E. McKenney
Browse files

rcu: Implement rcu_segcblist_is_offloaded() config dependent 



This commit simplifies the use of the rcu_segcblist_is_offloaded() API so
that its callers no longer need to check the RCU_NOCB_CPU Kconfig option.
Note that rcu_segcblist_is_offloaded() is defined in the header file,
which means that the generated code should be just as efficient as before.

Suggested-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 1eafe075

kernel/rcu/rcu_segcblist.h

+1 −1
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp) 
/* Is the specified rcu_segcblist offloaded?  */

static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)

{

	return rsclp->offloaded;

	return IS_ENABLED(CONFIG_RCU_NOCB_CPU) && rsclp->offloaded;

}



/*

kernel/rcu/tree.c

+7 −14
Original line number Diff line number Diff line
@@ -1603,8 +1603,7 @@ static bool __note_gp_changes(struct rcu_node *rnp, struct rcu_data *rdp) 
{

	bool ret = false;

	bool need_qs;

	const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&

			       rcu_segcblist_is_offloaded(&rdp->cblist);

	const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);



	raw_lockdep_assert_held_rcu_node(rnp);
@@ -2048,8 +2047,7 @@ static void rcu_gp_cleanup(void) 
		needgp = true;

	}

	/* Advance CBs to reduce false positives below. */

	offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&

		    rcu_segcblist_is_offloaded(&rdp->cblist);

	offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);

	if ((offloaded || !rcu_accelerate_cbs(rnp, rdp)) && needgp) {

		WRITE_ONCE(rcu_state.gp_flags, RCU_GP_FLAG_INIT);

		WRITE_ONCE(rcu_state.gp_req_activity, jiffies);
@@ -2248,8 +2246,7 @@ rcu_report_qs_rdp(struct rcu_data *rdp) 
	unsigned long flags;

	unsigned long mask;

	bool needwake = false;

	const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&

			       rcu_segcblist_is_offloaded(&rdp->cblist);

	const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);

	struct rcu_node *rnp;



	WARN_ON_ONCE(rdp->cpu != smp_processor_id());
@@ -2417,8 +2414,7 @@ static void rcu_do_batch(struct rcu_data *rdp) 
{

	int div;

	unsigned long flags;

	const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&

			       rcu_segcblist_is_offloaded(&rdp->cblist);

	const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);

	struct rcu_head *rhp;

	struct rcu_cblist rcl = RCU_CBLIST_INITIALIZER(rcl);

	long bl, count;
@@ -2675,8 +2671,7 @@ static __latent_entropy void rcu_core(void) 
	unsigned long flags;

	struct rcu_data *rdp = raw_cpu_ptr(&rcu_data);

	struct rcu_node *rnp = rdp->mynode;

	const bool offloaded = IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&

			       rcu_segcblist_is_offloaded(&rdp->cblist);

	const bool offloaded = rcu_segcblist_is_offloaded(&rdp->cblist);



	if (cpu_is_offline(smp_processor_id()))

		return;
@@ -2978,8 +2973,7 @@ __call_rcu(struct rcu_head *head, rcu_callback_t func) 
				   rcu_segcblist_n_cbs(&rdp->cblist));



	/* Go handle any RCU core processing required. */

	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&

	    unlikely(rcu_segcblist_is_offloaded(&rdp->cblist))) {

	if (unlikely(rcu_segcblist_is_offloaded(&rdp->cblist))) {

		__call_rcu_nocb_wake(rdp, was_alldone, flags); /* unlocks */

	} else {

		__call_rcu_core(rdp, head, flags);
@@ -3712,8 +3706,7 @@ static int rcu_pending(int user) 


	/* Has RCU gone idle with this CPU needing another grace period? */

	if (!gp_in_progress && rcu_segcblist_is_enabled(&rdp->cblist) &&

	    (!IS_ENABLED(CONFIG_RCU_NOCB_CPU) ||

	     !rcu_segcblist_is_offloaded(&rdp->cblist)) &&

	    !rcu_segcblist_is_offloaded(&rdp->cblist) &&

	    !rcu_segcblist_restempty(&rdp->cblist, RCU_NEXT_READY_TAIL))

		return 1;