From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
linux-kernel@vger.kernel.org,
Michael Jeanson <mjeanson@efficios.com>,
Alexei Starovoitov <ast@kernel.org>, Yonghong Song <yhs@fb.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
bpf@vger.kernel.org, Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH v4 1/5] tracing: Introduce faultable tracepoints
Date: Tue, 21 Nov 2023 17:03:00 +0100 [thread overview]
Message-ID: <20231121160300.GK8262@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <2a41f6cd-971d-4360-aeeb-a9cbf665bb72@paulmck-laptop>
On Tue, Nov 21, 2023 at 07:58:40AM -0800, Paul E. McKenney wrote:
> Tasks Trace RCU allows general blocking in its readers, not just the
> subject-to-priority-boosting blocking permitted within preemptible RCU
> readers. Restrictions on the use of Tasks Trace RCU are in place to allow
> getting away with this general blocking. Even systems generously endowed
> with memory are not going to do well when the RCU grace period is blocked
> on I/O, especially if that I/O is across a network to a slow file server.
>
> Which means a separate RCU instance is needed. Which is Tasks Trace RCU.
Separate instance not a problem, nor really the question.
What is the basic mechanism of task-tracing? Is it really the existing
tasks-rcu extended with read-side critical sections and call_rcu ?
If so, then why not have it be tasks-rcu?
Or is it a variant of the preemptible/SRCU class of RCUs that are
counter-array based? I suspect not.
So once again, what exactly is tasks-tracing ?
next prev parent reply other threads:[~2023-11-21 16:03 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-20 20:54 [PATCH v4 0/5] Faultable Tracepoints Mathieu Desnoyers
2023-11-20 20:54 ` [PATCH v4 1/5] tracing: Introduce faultable tracepoints Mathieu Desnoyers
2023-11-20 21:47 ` Peter Zijlstra
2023-11-20 22:18 ` Paul E. McKenney
2023-11-20 22:23 ` Peter Zijlstra
2023-11-20 23:56 ` Paul E. McKenney
2023-11-21 8:47 ` Peter Zijlstra
2023-11-21 14:06 ` Mathieu Desnoyers
2023-11-21 14:36 ` Peter Zijlstra
2023-11-21 14:40 ` Mathieu Desnoyers
2023-11-21 14:46 ` Peter Zijlstra
2023-11-21 14:56 ` Mathieu Desnoyers
2023-11-21 15:51 ` Paul E. McKenney
2023-11-21 15:52 ` Peter Zijlstra
2023-11-21 16:00 ` Mathieu Desnoyers
2023-11-21 16:07 ` Steven Rostedt
2023-11-21 16:11 ` Mathieu Desnoyers
2023-11-21 16:43 ` Paul E. McKenney
2023-11-21 16:50 ` Peter Zijlstra
2023-11-21 17:31 ` Peter Zijlstra
2023-11-21 16:41 ` Paul E. McKenney
2023-11-21 14:44 ` Steven Rostedt
2023-11-21 16:45 ` Paul E. McKenney
2023-11-21 15:58 ` Paul E. McKenney
2023-11-21 16:03 ` Peter Zijlstra [this message]
2023-11-21 16:46 ` Paul E. McKenney
2023-11-20 22:20 ` Steven Rostedt
2024-06-20 15:38 ` Mathieu Desnoyers
2023-11-20 20:54 ` [PATCH v4 2/5] tracing/ftrace: Add support for " Mathieu Desnoyers
2023-11-20 22:15 ` Peter Zijlstra
2024-06-20 15:04 ` Mathieu Desnoyers
2023-11-20 20:54 ` [PATCH v4 3/5] tracing/bpf-trace: add " Mathieu Desnoyers
2023-11-20 20:54 ` [PATCH v4 4/5] tracing/perf: " Mathieu Desnoyers
2023-11-20 20:54 ` [PATCH v4 5/5] tracing: convert sys_enter/exit to " Mathieu Desnoyers
2023-11-20 21:46 ` Peter Zijlstra
2024-06-20 15:05 ` Mathieu Desnoyers
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