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From: Frederic Weisbecker <frederic@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	Neeraj Upadhyay <neeraj.upadhyay@amd.com>,
	Uladzislau Rezki <urezki@gmail.com>,
	Zqiang <qiang.zhang1211@gmail.com>, rcu <rcu@vger.kernel.org>
Subject: [PATCH 1/4] rcu/nocb: Fix segcblist state machine comments about bypass
Date: Thu, 25 Apr 2024 16:18:32 +0200	[thread overview]
Message-ID: <20240425141835.19776-2-frederic@kernel.org> (raw)
In-Reply-To: <20240425141835.19776-1-frederic@kernel.org>

The parts explaining the bypass lifecycle in (de-)offloading are out
of date and/or wrong. Bypass is simply enabled whenever SEGCBLIST_RCU_CORE
flag is off.

Fix the comments accordingly.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 include/linux/rcu_segcblist.h | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/linux/rcu_segcblist.h b/include/linux/rcu_segcblist.h
index 659d13a7ddaa..1e5b4ef167ca 100644
--- a/include/linux/rcu_segcblist.h
+++ b/include/linux/rcu_segcblist.h
@@ -141,7 +141,7 @@ struct rcu_cblist {
  *  |                           SEGCBLIST_KTHREAD_GP                           |
  *  |                                                                          |
  *  |   CB/GP kthreads handle callbacks holding nocb_lock, local rcu_core()    |
- *  |   handles callbacks concurrently. Bypass enqueue is enabled.             |
+ *  |   handles callbacks concurrently. Bypass enqueue is disabled.            |
  *  |   Invoke RCU core so we make sure not to preempt it in the middle with   |
  *  |   leaving some urgent work unattended within a jiffy.                    |
  *  ----------------------------------------------------------------------------
@@ -154,8 +154,7 @@ struct rcu_cblist {
  *  |                           SEGCBLIST_KTHREAD_GP                           |
  *  |                                                                          |
  *  |   CB/GP kthreads and local rcu_core() handle callbacks concurrently      |
- *  |   holding nocb_lock. Wake up CB and GP kthreads if necessary. Disable    |
- *  |   bypass enqueue.                                                        |
+ *  |   holding nocb_lock. Wake up CB and GP kthreads if necessary.            |
  *  ----------------------------------------------------------------------------
  *                                      |
  *                                      v
@@ -185,7 +184,7 @@ struct rcu_cblist {
  *  |                                                                          |
  *  | Callbacks processed by rcu_core() from softirqs or local                 |
  *  | rcuc kthread, while holding nocb_lock. Forbid nocb_timer to be armed.    |
- *  | Flush pending nocb_timer. Flush nocb bypass callbacks.                   |
+ *  | Flush pending nocb_timer.                                                |
  *  ----------------------------------------------------------------------------
  *                                      |
  *                                      v
-- 
2.44.0


  reply	other threads:[~2024-04-25 14:18 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-25 14:18 [PATCH 0/4] rcu/nocb cleanups Frederic Weisbecker
2024-04-25 14:18 ` Frederic Weisbecker [this message]
2024-04-25 14:18 ` [PATCH 2/4] rcu/nocb: Fix segcblist state machine stale comments about timers Frederic Weisbecker
2024-04-25 14:18 ` [PATCH 3/4] rcu/nocb: Use kthread parking instead of ad-hoc implementation Frederic Weisbecker
2024-04-25 14:18 ` [PATCH 4/4] rcu/nocb: Remove buggy bypass lock contention mitigation Frederic Weisbecker
2024-04-29 21:02 ` [PATCH 0/4] rcu/nocb cleanups Paul E. McKenney

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