From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [PATCH v2 9/9] perf,tracing: Allow function tracing when !RCU Date: Fri, 14 Feb 2020 17:48:45 -0500 Message-ID: <20200214174845.715de27b@gandalf.local.home> References: <20200212210139.382424693@infradead.org> <20200212210750.312024711@infradead.org> <121a6b11-2fe1-6d9b-2861-a8ef8b42c452@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mail.kernel.org ([198.145.29.99]:47430 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726164AbgBNWst (ORCPT ); Fri, 14 Feb 2020 17:48:49 -0500 In-Reply-To: <121a6b11-2fe1-6d9b-2861-a8ef8b42c452@amd.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Kim Phillips Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com On Fri, 14 Feb 2020 14:38:14 -0600 Kim Phillips wrote: > On 2/12/20 3:01 PM, Peter Zijlstra wrote: > > Since perf is now able to deal with !rcu_is_watching() contexts, > > remove the restraint. > > > > Signed-off-by: Peter Zijlstra (Intel) > > --- > > kernel/trace/trace_event_perf.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > --- a/kernel/trace/trace_event_perf.c > > +++ b/kernel/trace/trace_event_perf.c > > @@ -477,7 +477,7 @@ static int perf_ftrace_function_register > > { > > struct ftrace_ops *ops = &event->ftrace_ops; > > > > - ops->flags = FTRACE_OPS_FL_RCU; > > + ops->flags = 0; > > ops->func = perf_ftrace_function_call; > > ops->private = (void *)(unsigned long)nr_cpu_ids; > > If this is the last user of the flag, should all remaining > FTRACE_OPS_FL_RCU references be removed, too? Let's wait till Peter's patches goes through a merge cycle or two. I want to make sure there's no other RCU issues that pop up before we remove this infrastructure. -- Steve