[PATCH 07/11] rcu/nocb: Remove halfway (de-)offloading handling from rcu_core()'s QS reporting

From: Frederic Weisbecker
Date: Thu May 30 2024 - 09:48:29 EST


RCU core can't be running anymore while in the middle of (de-)offloading
since this sort of transition now only applies to offline CPUs.

The locked callback acceleration handling during the transition can
therefore be removed.

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
---
kernel/rcu/tree.c | 13 -------------
1 file changed, 13 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index e904c187c281..c502a38dc5f3 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2381,7 +2381,6 @@ rcu_report_qs_rdp(struct rcu_data *rdp)
{
unsigned long flags;
unsigned long mask;
- bool needacc = false;
struct rcu_node *rnp;

WARN_ON_ONCE(rdp->cpu != smp_processor_id());
@@ -2418,23 +2417,11 @@ rcu_report_qs_rdp(struct rcu_data *rdp)
* to return true. So complain, but don't awaken.
*/
WARN_ON_ONCE(rcu_accelerate_cbs(rnp, rdp));
- } else if (!rcu_segcblist_completely_offloaded(&rdp->cblist)) {
- /*
- * ...but NOCB kthreads may miss or delay callbacks acceleration
- * if in the middle of a (de-)offloading process.
- */
- needacc = true;
}

rcu_disable_urgency_upon_qs(rdp);
rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
/* ^^^ Released rnp->lock */
-
- if (needacc) {
- rcu_nocb_lock_irqsave(rdp, flags);
- rcu_accelerate_cbs_unlocked(rnp, rdp);
- rcu_nocb_unlock_irqrestore(rdp, flags);
- }
}
}

--
2.45.1