[PATCH v3 tip/core/rcu 03/40] srcu: Consolidate batch checking into rcu_all_batches_empty()

From: Paul E. McKenney
Date: Wed Apr 19 2017 - 13:07:54 EST


The srcu_reschedule() function invokes rcu_batch_empty() on each of
the four rcu_batch structures in the srcu_struct in question twice.
Given that this check will also be needed in cleanup_srcu_struct(), this
commit consolidates these four checks into a new rcu_all_batches_empty()
function.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
kernel/rcu/srcu.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c
index ef3bcfb15b39..ba41a5d04b49 100644
--- a/kernel/rcu/srcu.c
+++ b/kernel/rcu/srcu.c
@@ -65,6 +65,17 @@ static inline bool rcu_batch_empty(struct rcu_batch *b)
}

/*
+ * Are all batches empty for the specified srcu_struct?
+ */
+static inline bool rcu_all_batches_empty(struct srcu_struct *sp)
+{
+ return rcu_batch_empty(&sp->batch_done) &&
+ rcu_batch_empty(&sp->batch_check1) &&
+ rcu_batch_empty(&sp->batch_check0) &&
+ rcu_batch_empty(&sp->batch_queue);
+}
+
+/*
* Remove the callback at the head of the specified rcu_batch structure
* and return a pointer to it, or return NULL if the structure is empty.
*/
@@ -619,15 +630,9 @@ static void srcu_reschedule(struct srcu_struct *sp)
{
bool pending = true;

- if (rcu_batch_empty(&sp->batch_done) &&
- rcu_batch_empty(&sp->batch_check1) &&
- rcu_batch_empty(&sp->batch_check0) &&
- rcu_batch_empty(&sp->batch_queue)) {
+ if (rcu_all_batches_empty(sp)) {
spin_lock_irq(&sp->queue_lock);
- if (rcu_batch_empty(&sp->batch_done) &&
- rcu_batch_empty(&sp->batch_check1) &&
- rcu_batch_empty(&sp->batch_check0) &&
- rcu_batch_empty(&sp->batch_queue)) {
+ if (rcu_all_batches_empty(sp)) {
sp->running = false;
pending = false;
}
--
2.5.2