diff mbox series

[4/5] srcu: No need to advance/accelerate if no callback enqueued

Message ID 20231003232903.7109-5-frederic@kernel.org
State New
Headers
Series srcu fixes |

Commit Message

Frederic Weisbecker Oct. 3, 2023, 11:29 p.m. UTC 
  While in grace period start, there is nothing to accelerate and
therefore no need to advance the callbacks either if no callback is
to be enqueued.

Spare these needless operations in this case.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/rcu/srcutree.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index e9356a103626..2bfc8ed1eed2 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -1261,9 +1261,11 @@  static unsigned long srcu_gp_start_if_needed(struct srcu_struct *ssp,
 	 *     period (gp_num = X + 8). So acceleration fails.
 	 */
 	s = rcu_seq_snap(&ssp->srcu_sup->srcu_gp_seq);
-	rcu_segcblist_advance(&sdp->srcu_cblist,
-			      rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
-	WARN_ON_ONCE(!rcu_segcblist_accelerate(&sdp->srcu_cblist, s) && rhp);
+	if (rhp) {
+		rcu_segcblist_advance(&sdp->srcu_cblist,
+				      rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
+		WARN_ON_ONCE(!rcu_segcblist_accelerate(&sdp->srcu_cblist, s));
+	}
 	if (ULONG_CMP_LT(sdp->srcu_gp_seq_needed, s)) {
 		sdp->srcu_gp_seq_needed = s;
 		needgp = true;