From: Peter Zijlstra <peterz@infradead.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
"Paul E. McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Joel Fernandes <joel@joelfernandes.org>,
John Ogness <john.ogness@linutronix.de>,
Josh Triplett <josh@joshtriplett.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Waiman Long <longman@redhat.com>, Will Deacon <will@kernel.org>,
Zqiang <qiang.zhang1211@gmail.com>
Subject: Re: [RFC PATCH] srcu: Use try-lock lockdep annotation for NMI-safe access.
Date: Thu, 28 Sep 2023 10:05:56 +0200 [thread overview]
Message-ID: <20230928080556.GE9829@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <ZRUX0YUrXfepRGKE@Boquns-Mac-mini.home>
On Wed, Sep 27, 2023 at 11:06:09PM -0700, Boqun Feng wrote:
> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index e85b5ad3e206..1af8d44e5eb4 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -5727,8 +5727,9 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
> return;
>
> if (unlikely(!lockdep_enabled())) {
> + /* Only do NMI context checking if it's a check lock */
> /* XXX allow trylock from NMI ?!? */
> - if (lockdep_nmi() && !trylock) {
> + if (check && lockdep_nmi() && !trylock) {
> struct held_lock hlock;
>
> hlock.acquire_ip = ip;
>
> Peter, thoughts?
>
I think I prefer the trylock one. Fundamentally trylock conveys the 'we
wont block' thing. Making 'lock' sometimes work for NMI is just
confusing.
next prev parent reply other threads:[~2023-09-28 8:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-27 16:02 [RFC PATCH] srcu: Use try-lock lockdep annotation for NMI-safe access Sebastian Andrzej Siewior
2023-09-28 6:06 ` Boqun Feng
2023-09-28 6:33 ` Sebastian Andrzej Siewior
2023-09-28 8:05 ` Peter Zijlstra [this message]
2023-09-28 8:09 ` Peter Zijlstra
2023-09-28 14:54 ` Boqun Feng
2023-09-28 15:29 ` Peter Zijlstra
2023-09-28 17:09 ` Boqun Feng
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=20230928080556.GE9829@noisy.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=bigeasy@linutronix.de \
--cc=boqun.feng@gmail.com \
--cc=frederic@kernel.org \
--cc=jiangshanlai@gmail.com \
--cc=joel@joelfernandes.org \
--cc=john.ogness@linutronix.de \
--cc=josh@joshtriplett.org \
--cc=linux-kernel@vger.kernel.org \
--cc=longman@redhat.com \
--cc=mathieu.desnoyers@efficios.com \
--cc=mingo@redhat.com \
--cc=paulmck@kernel.org \
--cc=qiang.zhang1211@gmail.com \
--cc=quic_neeraju@quicinc.com \
--cc=rcu@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
/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