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Commit 8ef0f37e authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Open-code the rcu_cblist_empty() function 



Because the rcu_cblist_empty() just samples the ->head pointer, and
because the rcu_cblist structure is quite straightforward, it makes
sense to open-code rcu_cblist_empty(p) as !p->head, cutting out a
level of indirection.  This commit makes this change.

Reported-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
parent 98059b98

kernel/rcu/rcu_segcblist.h

+1 −7
Original line number Diff line number Diff line
@@ -22,12 +22,6 @@ 


#include <linux/rcu_segcblist.h>



/* Is simple callback list empty? */

static inline bool rcu_cblist_empty(struct rcu_cblist *rclp)

{

	return !rclp->head;

}



/* Return number of callbacks in simple callback list. */

static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)

{
@@ -66,7 +60,7 @@ static inline struct rcu_head *rcu_cblist_head(struct rcu_cblist *rclp) 
 */

static inline struct rcu_head **rcu_cblist_tail(struct rcu_cblist *rclp)

{

	WARN_ON_ONCE(rcu_cblist_empty(rclp));

	WARN_ON_ONCE(!rclp->head);

	return rclp->tail;

}

kernel/rcu/tree.c

+4 −5
Original line number Diff line number Diff line
@@ -2647,9 +2647,9 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) 


	/* First adopt the ready-to-invoke callbacks, then the done ones. */

	rcu_segcblist_insert_done_cbs(&rdp->cblist, &rsp->orphan_done);

	WARN_ON_ONCE(!rcu_cblist_empty(&rsp->orphan_done));

	WARN_ON_ONCE(rsp->orphan_done.head);

	rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rsp->orphan_pend);

	WARN_ON_ONCE(!rcu_cblist_empty(&rsp->orphan_pend));

	WARN_ON_ONCE(rsp->orphan_pend.head);

	WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) !=

		     !rcu_segcblist_n_cbs(&rdp->cblist));

}
@@ -2800,9 +2800,8 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) 


	local_irq_save(flags);

	count = -rcu_cblist_n_cbs(&rcl);

	trace_rcu_batch_end(rsp->name, count, !rcu_cblist_empty(&rcl),

			    need_resched(), is_idle_task(current),

			    rcu_is_callbacks_kthread());

	trace_rcu_batch_end(rsp->name, count, !!rcl.head, need_resched(),

			    is_idle_task(current), rcu_is_callbacks_kthread());



	/* Update counts and requeue any remaining callbacks. */

	rcu_segcblist_insert_done_cbs(&rdp->cblist, &rcl);

kernel/rcu/tree_plugin.h

+2 −2
Original line number Diff line number Diff line
@@ -1942,12 +1942,12 @@ static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, 
		return false;



	/* First, enqueue the donelist, if any.  This preserves CB ordering. */

	if (!rcu_cblist_empty(&rsp->orphan_done)) {

	if (rsp->orphan_done.head) {

		__call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_done),

					rcu_cblist_tail(&rsp->orphan_done),

					ql, qll, flags);

	}

	if (!rcu_cblist_empty(&rsp->orphan_pend)) {

	if (rsp->orphan_pend.head) {

		__call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_pend),

					rcu_cblist_tail(&rsp->orphan_pend),

					ql, qll, flags);