Re: [PATCH 1/2] locking: Provide a low overhead do_arch_spin_lock() API

[Steven Rostedt]

On Wed, 21 Sep 2022 09:21:51 -0400
Waiman Long <longman@xxxxxxxxxx> 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@xxxxxxxxxx>

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