mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
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


  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260103002343.6599-15-joelagnelf@nvidia.com \
    --to=joelagnelf@nvidia.com \
    --cc=boqun.feng@gmail.com \
    --cc=frederic@kernel.org \
    --cc=jiangshanlai@gmail.com \
    --cc=joel@joelfernandes.org \
    --cc=josh@joshtriplett.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=neeraj.upadhyay@kernel.org \
    --cc=paulmck@kernel.org \
    --cc=qiang.zhang@linux.dev \
    --cc=rcu@vger.kernel.org \
    --cc=rostedt@goodmis.org \
    --cc=urezki@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®