From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7BC3456743 for ; Tue, 21 Nov 2023 14:44:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5174C433C8; Tue, 21 Nov 2023 14:44:29 +0000 (UTC) Date: Tue, 21 Nov 2023 09:44:44 -0500 From: Steven Rostedt To: Peter Zijlstra Cc: Mathieu Desnoyers , "Paul E. McKenney" , Masami Hiramatsu , linux-kernel@vger.kernel.org, Michael Jeanson , Alexei Starovoitov , Yonghong Song , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , bpf@vger.kernel.org, Joel Fernandes Subject: Re: [PATCH v4 1/5] tracing: Introduce faultable tracepoints Message-ID: <20231121094444.04701bdc@gandalf.local.home> In-Reply-To: <20231121143647.GI8262@noisy.programming.kicks-ass.net> References: <20231120205418.334172-1-mathieu.desnoyers@efficios.com> <20231120205418.334172-2-mathieu.desnoyers@efficios.com> <20231120214742.GC8262@noisy.programming.kicks-ass.net> <62c6e37c-88cc-43f7-ac3f-1c14059277cc@paulmck-laptop> <20231120222311.GE8262@noisy.programming.kicks-ass.net> <20231121084706.GF8262@noisy.programming.kicks-ass.net> <20231121143647.GI8262@noisy.programming.kicks-ass.net> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 21 Nov 2023 15:36:47 +0100 Peter Zijlstra wrote: > > Still utterly confused about what task-tracing rcu is and how it is > different from preemptible rcu. Is this similar to synchronize_rcu_tasks()? As I understand that one (grace period continues until all tasks have voluntarily scheduled or gone into user space). But I'm a bit confused by synchronize_rcu_tasks_trace()? Note, that for syncronize_rcu_tasks() the critical sections must not call schedule (although it is OK to be preempted). -- Steve