From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85383C35242 for ; Fri, 14 Feb 2020 22:48:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5293C222C4 for ; Fri, 14 Feb 2020 22:48:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727799AbgBNWst (ORCPT ); Fri, 14 Feb 2020 17:48:49 -0500 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 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 629A62081E; Fri, 14 Feb 2020 22:48:47 +0000 (UTC) Date: Fri, 14 Feb 2020 17:48:45 -0500 From: Steven Rostedt 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 Subject: Re: [PATCH v2 9/9] perf,tracing: Allow function tracing when !RCU Message-ID: <20200214174845.715de27b@gandalf.local.home> In-Reply-To: <121a6b11-2fe1-6d9b-2861-a8ef8b42c452@amd.com> References: <20200212210139.382424693@infradead.org> <20200212210750.312024711@infradead.org> <121a6b11-2fe1-6d9b-2861-a8ef8b42c452@amd.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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