From: Steven Rostedt <rostedt@goodmis.org>
To: Waiman Long <longman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Boqun Feng <boqun.feng@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] locking: Provide a low overhead do_arch_spin_lock() API
Date: Wed, 21 Sep 2022 18:06:40 -0400 [thread overview]
Message-ID: <20220921180640.032d16fd@gandalf.local.home> (raw)
In-Reply-To: <20220921132152.1622616-2-longman@redhat.com>
On Wed, 21 Sep 2022 09:21:51 -0400
Waiman Long <longman@redhat.com> wrote:
> There are some code paths in the kernel like tracing or rcu where they
> want to use a spinlock without the lock debugging overhead (lockdep,
> etc). Provide a do_arch_spin_lock() API with proper preemption disabling
> and enabling without any debugging or tracing overhead.
>
> Signed-off-by: Waiman Long <longman@redhat.com>
Please don't do this. arch_spin_lock() is very special, and if tracing did
it wrong, then it needs to be fixed in the tracing code.
Let's not add handlers to make it easier to use arch_spin_lock(). Tracing
is special and arch_spin_lock() helps keep it from tracing itself.
-- Steve
next prev parent reply other threads:[~2022-09-21 22:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 13:21 [PATCH 0/2] locking, tracing: Fix incorrect use of arch_spin_lock() Waiman Long
2022-09-21 13:21 ` [PATCH 1/2] locking: Provide a low overhead do_arch_spin_lock() API Waiman Long
2022-09-21 22:06 ` Steven Rostedt [this message]
2022-09-22 0:51 ` Waiman Long
2022-09-21 13:21 ` [PATCH 2/2] tracing: Use proper " Waiman Long
2022-09-21 22:17 ` Steven Rostedt
2022-09-22 0:50 ` Waiman Long
[not found] ` <3789bf4d-d699-63d4-c97b-c8d9524cbc2f@redhat.com>
2022-09-22 2:08 ` Steven Rostedt
2022-09-22 7:55 ` Peter Zijlstra
2022-09-22 12:25 ` Waiman Long
2022-09-22 12:40 ` Steven Rostedt
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