From: Joel Fernandes <joelagnelf@nvidia.com>
To: linux-kernel@vger.kernel.org
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
Joel Fernandes <joelagnelf@nvidia.com>,
Josh Triplett <josh@joshtriplett.org>,
Boqun Feng <boqun.feng@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang@linux.dev>,
Uladzislau Rezki <urezki@gmail.com>,
joel@joelfernandes.org, rcu@vger.kernel.org
Subject: [PATCH RFC 14/14] rcu: Remove checking of per-cpu blocked list against the node list
Date: Fri, 2 Jan 2026 19:23:43 -0500 [thread overview]
Message-ID: <20260103002343.6599-15-joelagnelf@nvidia.com> (raw)
In-Reply-To: <20260103002343.6599-1-joelagnelf@nvidia.com>
Now that the verification check consistently is verified, remove it. It
is still kept in the patch series for illustration/testing purposes.
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
kernel/rcu/tree.c | 20 --------------------
1 file changed, 20 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 468388970c98..9d9d7c5ff3fc 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1900,26 +1900,6 @@ static noinline_for_stack bool rcu_gp_init(void)
arch_spin_lock(&rcu_state.ofl_lock);
raw_spin_lock_rcu_node(rnp);
rcu_promote_blocked_tasks(rnp);
-#ifdef CONFIG_RCU_PER_CPU_BLOCKED_LISTS
- /*
- * Verify rdp lists consistent with rnp list. Since the unlock
- * path removes from rdp before rnp, we can have tasks that are
- * on rnp but not on rdp (in the middle of being removed).
- * Therefore rnp_count >= rdp_total is the expected invariant.
- */
- rnp_count = 0;
- rdp_total = 0;
- list_for_each_entry(t_verify, &rnp->blkd_tasks, rcu_node_entry)
- rnp_count++;
- for (cpu_verify = rnp->grplo; cpu_verify <= rnp->grphi; cpu_verify++) {
- rdp_cpu = per_cpu_ptr(&rcu_data, cpu_verify);
- raw_spin_lock(&rdp_cpu->blkd_lock);
- list_for_each_entry(t_rdp, &rdp_cpu->blkd_list, rcu_rdp_entry)
- rdp_total++;
- raw_spin_unlock(&rdp_cpu->blkd_lock);
- }
- WARN_ON_ONCE(rnp_count < rdp_total);
-#endif
if (rnp->qsmaskinit == rnp->qsmaskinitnext &&
!rnp->wait_blkd_tasks) {
/* Nothing to do on this leaf rcu_node structure. */
--
2.34.1
next prev parent reply other threads:[~2026-01-03 0:24 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-03 0:23 [PATCH RFC 00/14] rcu: Reduce rnp->lock contention with per-CPU blocked task lists Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 01/14] rcu: Add WARN_ON_ONCE for blocked flag invariant in exit_rcu() Joel Fernandes
2026-01-05 15:31 ` Steven Rostedt
2026-01-05 15:44 ` Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 02/14] rcu: Add per-CPU blocked task lists for PREEMPT_RCU Joel Fernandes
2026-01-05 15:48 ` Steven Rostedt
2026-01-03 0:23 ` [PATCH RFC 03/14] rcu: Early return during unlock for tasks only on per-CPU blocked list Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 04/14] rcu: Promote blocked tasks from per-CPU to rnp lists Joel Fernandes
2026-01-05 15:59 ` Steven Rostedt
2026-01-09 3:52 ` Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 05/14] rcu: Promote blocked tasks for expedited GPs Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 06/14] rcu: Promote per-CPU blocked tasks before checking for blocked readers Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 07/14] rcu: Promote late-arriving blocked tasks before reporting QS Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 08/14] rcu: Promote blocked tasks before QS report in force_qs_rnp() Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 09/14] rcu: Promote blocked tasks before QS report in rcutree_report_cpu_dead() Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 10/14] rcu: Promote blocked tasks before QS report in rcu_gp_init() Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 11/14] rcu: Add per-CPU blocked list check in exit_rcu() Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 12/14] rcu: Skip per-CPU list addition when GP already started Joel Fernandes
2026-01-03 0:23 ` [PATCH RFC 13/14] rcu: Skip rnp addition when no grace period waiting Joel Fernandes
2026-01-03 0:23 ` Joel Fernandes [this message]
2026-01-05 16:46 ` [PATCH RFC 00/14] rcu: Reduce rnp->lock contention with per-CPU blocked task lists Paul E. McKenney
2026-01-06 0:55 ` Joel Fernandes
2026-01-06 15:08 ` Joel Fernandes
2026-01-06 19:24 ` Paul E. McKenney
2026-01-06 21:24 ` Joel Fernandes
2026-01-09 2:00 ` Paul E. McKenney
2026-01-06 19:17 ` Paul E. McKenney
2026-01-06 20:19 ` Steven Rostedt
2026-01-06 20:35 ` Paul E. McKenney
2026-01-06 20:49 ` Joel Fernandes
2026-01-09 1:55 ` Paul E. McKenney
2026-01-06 20:40 ` Joel Fernandes
2026-01-09 1:52 ` Paul E. McKenney
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