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Date: Mon, 5 May 2025 11:59:28 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Doug Anderson <dianders@chromium.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Masami
 Hiramatsu <mhiramat@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
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 <akpm@linux-foundation.org>, Jason Wessel <jason.wessel@windriver.com>,
 Daniel Thompson <danielt@kernel.org>
Subject: Re: [PATCH 05/12] tracing: kdb: Use tracer_tracing_on/off() instead
 of setting per CPU disabled
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On Mon, 5 May 2025 08:42:52 -0700
Doug Anderson <dianders@chromium.org> wrote:

> This new change seems less safe than the old one. Previously you'd

Well, it matters what you your definition of "safe" is ;-)

The new change prevents the ring buffer from having anything written to it,
where as the old change didn't disable everything.

> always increment by one at the start of the function and decrement by
> one at the end. Now at the start of the function you'll set
> "buffer_disabled" to 1 and at the end you'll set it to 0. If
> "buffer_disabled" was already 1 at the start of the function your new
> sequence will end up having the side effect of changing it to 0.

Good point. How about I add a tracer_tracing_disable() and
tracer_tracing_enable() that is not an on off switch and uses:
ring_buffer_disable/enable() that decrements/increments disabling of the
ring buffer?

That way it keeps the same semantics.

-- STeve