From: "Paul E. McKenney" <paulmck@kernel.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Boqun Feng <boqun.feng@gmail.com>,
linux-rt-devel@lists.linux.dev, rcu@vger.kernel.org,
linux-trace-kernel@vger.kernel.org,
Frederic Weisbecker <frederic@kernel.org>,
Joel Fernandes <joelagnelf@nvidia.com>,
Josh Triplett <josh@joshtriplett.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Uladzislau Rezki <urezki@gmail.com>,
Zqiang <qiang.zhang@linux.dev>
Subject: Re: [RFC PATCH 1/2] rcu: Add rcu_read_lock_notrace()
Date: Mon, 14 Jul 2025 09:34:16 -0700 [thread overview]
Message-ID: <ebad20d8-7b04-4c32-97a9-8ae058bdaedc@paulmck-laptop> (raw)
In-Reply-To: <16dd7f3c-1c0f-4dfd-bfee-4c07ec844b72@paulmck-laptop>
On Fri, Jul 11, 2025 at 10:05:26AM -0700, Paul E. McKenney wrote:
> On Fri, Jul 11, 2025 at 09:46:25AM -0400, Mathieu Desnoyers wrote:
[ . . . ]
> > AFAIU the goal here is to turn the guard(preempt_notrace)() into a
> > guard(rcu_notrace)() because the preempt-off critical sections don't
> > agree with BPF.
>
> OK, got it, thank you!
>
> The combination of BPF and CONFIG_PREEMPT_RT certainly has provided at
> least its share of entertainment, that is for sure. ;-)
Is there a similar issue with CONFIG_PREEMPT_LAZY, given that in that
case rcu_read_unlock() maps to preempt_enable(), which also can invoke
the scheduler?
Thanx, Paul
next prev parent reply other threads:[~2025-07-14 16:34 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-13 15:22 [RFC PATCH 0/2] Switch tracing from sched-RCU to preempt-RCU Sebastian Andrzej Siewior
2025-06-13 15:22 ` [RFC PATCH 1/2] rcu: Add rcu_read_lock_notrace() Sebastian Andrzej Siewior
2025-06-18 17:21 ` Boqun Feng
2025-06-20 8:43 ` Sebastian Andrzej Siewior
2025-06-20 11:23 ` Paul E. McKenney
2025-06-23 10:49 ` Sebastian Andrzej Siewior
2025-06-23 18:13 ` Paul E. McKenney
2025-07-07 21:56 ` Paul E. McKenney
2025-07-08 19:40 ` Mathieu Desnoyers
2025-07-08 20:49 ` Paul E. McKenney
2025-07-09 14:31 ` Mathieu Desnoyers
2025-07-09 18:33 ` Paul E. McKenney
2025-07-11 13:46 ` Mathieu Desnoyers
2025-07-11 17:05 ` Paul E. McKenney
2025-07-14 16:34 ` Paul E. McKenney [this message]
2025-07-15 19:56 ` Mathieu Desnoyers
2025-07-15 23:23 ` Paul E. McKenney
2025-07-15 19:54 ` Mathieu Desnoyers
2025-07-15 23:18 ` Paul E. McKenney
2025-07-16 0:42 ` Paul E. McKenney
2025-07-16 4:41 ` Paul E. McKenney
2025-07-16 15:09 ` Steven Rostedt
2025-07-16 20:35 ` Paul E. McKenney
2025-07-16 22:54 ` Paul E. McKenney
2025-07-17 13:14 ` Mathieu Desnoyers
2025-07-17 14:46 ` Mathieu Desnoyers
2025-07-17 15:18 ` Paul E. McKenney
2025-07-17 19:36 ` Mathieu Desnoyers
2025-07-17 21:27 ` Paul E. McKenney
2026-01-07 1:26 ` Joel Fernandes
2026-01-06 15:08 ` Mathieu Desnoyers
2026-01-06 18:30 ` Paul E. McKenney
2026-01-06 18:43 ` Mathieu Desnoyers
2025-07-17 14:57 ` Alexei Starovoitov
2025-07-17 15:12 ` Steven Rostedt
2025-07-17 15:27 ` Alexei Starovoitov
2025-07-17 15:40 ` Steven Rostedt
2025-07-17 15:55 ` Steven Rostedt
2025-07-17 16:02 ` Alexei Starovoitov
2025-07-17 16:19 ` Steven Rostedt
2025-07-17 17:38 ` Mathieu Desnoyers
2025-07-17 16:04 ` Paul E. McKenney
2025-07-17 15:44 ` Paul E. McKenney
2025-07-17 15:30 ` Paul E. McKenney
2025-07-17 15:07 ` Paul E. McKenney
2025-07-17 19:04 ` [PATCH RFC 6/4] srcu: Add guards for SRCU-fast readers Paul E. McKenney
2025-07-17 19:19 ` Steven Rostedt
2025-07-17 19:51 ` Paul E. McKenney
2025-07-17 19:56 ` Steven Rostedt
2025-07-17 20:38 ` Paul E. McKenney
2025-07-19 0:28 ` [RFC PATCH 1/2] rcu: Add rcu_read_lock_notrace() Paul E. McKenney
2025-06-13 15:22 ` [RFC PATCH 2/2] trace: Use rcu_read_lock() instead preempt_disable() Sebastian Andrzej Siewior
2025-06-13 15:38 ` [RFC PATCH 0/2] Switch tracing from sched-RCU to preempt-RCU Mathieu Desnoyers
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