linux-kernel - Re: [PATCH 0/6] tracing/ring-buffer: Fix wakeup of ring buffer waiters

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Message-ID: <20240310121942.7c0a613b@rorschach.local.home>
Date: Sun, 10 Mar 2024 12:19:42 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org, Masami
 Hiramatsu <mhiramat@...nel.org>, Mark Rutland <mark.rutland@....com>,
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>, Andrew Morton
 <akpm@...ux-foundation.org>, joel@...lfernandes.org, linke li
 <lilinke99@...com>, Rabin Vincent <rabin@....in>
Subject: Re: [PATCH 0/6] tracing/ring-buffer: Fix wakeup of ring buffer
 waiters

On Fri, 8 Mar 2024 13:41:59 -0800
Linus Torvalds <torvalds@...ux-foundation.org> wrote:

> On Fri, 8 Mar 2024 at 13:39, Linus Torvalds
> <torvalds@...ux-foundation.org> wrote:
> >
> > So the above "complexity" is *literally* just changing the
> >
> >                   (new = atomic_read_acquire(&my->seq)) != old
> >
> > condition to
> >
> >                   should_exit ||
> >                   (new = atomic_read_acquire(&my->seq)) != old  
> 
> .. and obviously you'll need to add the exit condition to the actual
> "deal with events" loop too.

I haven't had a chance to rework this part of the patches, but I have
some other fixes to push to you from earlier this week, and I think the
first three patches of this series are also fine. As the loop in
ring_buffer_wait() isn't needed, and patch 2 and 3 are trivial bugs.

I'll send you a pull request for that work and I'll work on this code
later.

-- Steve