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>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <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
Date: Mon, 5 May 2025 11:59:28 -0400 [thread overview]
Message-ID: <20250505115928.2fb446b6@gandalf.local.home> (raw)
In-Reply-To: <CAD=FV=UEnL7ztSfqAHS1Y=VwwYSyT=rfE7ZiUPLnDnMQNTcPjw@mail.gmail.com>
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
next prev parent reply other threads:[~2025-05-05 15:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-02 20:51 [PATCH 00/12] tracing: Remove most uses of "disabled" field Steven Rostedt
2025-05-02 20:51 ` [PATCH 01/12] tracing/mmiotrace: Remove reference to unused per CPU data pointer Steven Rostedt
2025-05-02 20:51 ` [PATCH 02/12] tracing: Do not bother setting "disabled" field for ftrace_dump_one() Steven Rostedt
2025-05-02 20:51 ` [PATCH 03/12] ftrace: Do not bother checking per CPU "disabled" flag Steven Rostedt
2025-05-02 20:51 ` [PATCH 04/12] tracing: Just use this_cpu_read() to access ignore_pid Steven Rostedt
2025-05-02 20:51 ` [PATCH 05/12] tracing: kdb: Use tracer_tracing_on/off() instead of setting per CPU disabled Steven Rostedt
2025-05-05 5:05 ` kernel test robot
2025-05-05 15:42 ` Doug Anderson
2025-05-05 15:59 ` Steven Rostedt [this message]
2025-05-02 20:51 ` [PATCH 06/12] ftrace: Do not disabled function graph based on "disabled" field Steven Rostedt
2025-05-02 20:51 ` [PATCH 07/12] tracing: Do not use per CPU array_buffer.data->disabled for cpumask Steven Rostedt
2025-05-02 20:51 ` [PATCH 08/12] ring-buffer: Add ring_buffer_record_is_on_cpu() Steven Rostedt
2025-05-02 20:51 ` [PATCH 09/12] tracing: branch: Use trace_tracing_is_on_cpu() instead of "disabled" field Steven Rostedt
2025-05-03 10:10 ` kernel test robot
2025-05-05 12:11 ` kernel test robot
2025-05-02 20:51 ` [PATCH 10/12] tracing: Convert the per CPU "disabled" counter to local from atomic Steven Rostedt
2025-05-02 20:51 ` [PATCH 11/12] tracing: Use atomic_inc_return() for updating "disabled" counter in irqsoff tracer Steven Rostedt
2025-05-02 20:51 ` [PATCH 12/12] tracing: Remove unused buffer_page field from trace_array_cpu structure Steven Rostedt
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