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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 3603AC34056 for ; Wed, 19 Feb 2020 17:40:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 101922465D for ; Wed, 19 Feb 2020 17:40:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582134028; bh=i92S40+jzCfAaut1HbIbCYpH99Q9SSIALtCHn4Qn0eY=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=CdD0VRIwE3NLKPUMBrL0cdmmLQmku8X1hOUUbDQsiKSYC/AwH4jltmps7nNYPVcJq Vmq1DK3/0aei33CRFfujMQWwCDL3zeyPRnnyd0iCoYOjOQDkJlb/UszFSDx/lmJxUm 1+6g34oDR8CzlwedVIYNdDlpMHzSzSkkepV+bFo8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726776AbgBSRk1 (ORCPT ); Wed, 19 Feb 2020 12:40:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:48024 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726638AbgBSRk0 (ORCPT ); Wed, 19 Feb 2020 12:40:26 -0500 Received: from paulmck-ThinkPad-P72.home (50-39-105-78.bvtn.or.frontiernet.net [50.39.105.78]) (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 27FA220801; Wed, 19 Feb 2020 17:40:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582134026; bh=i92S40+jzCfAaut1HbIbCYpH99Q9SSIALtCHn4Qn0eY=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=gu/5ow6Hv34c40kPs1ZHrz3VzubkdmEsjjyh3Nr7n/t6WHgyI3H/5XLTnyR4Bpysq pPA6ygMa0irWXaC2FQzYFCWIi6hY3zOY9VsIvFj1x+2Tf49aKmGLEqPMo13u6YAr6r R/2JNcN/qnS/qXTxavVI0kSOVz9LLv8QbSY7gRrQ= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id E215A35209B0; Wed, 19 Feb 2020 09:40:25 -0800 (PST) Date: Wed, 19 Feb 2020 09:40:25 -0800 From: "Paul E. McKenney" To: Steven Rostedt 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, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, frederic@kernel.org, dan.carpenter@oracle.com, mhiramat@kernel.org Subject: Re: [PATCH v3 13/22] tracing: Remove regular RCU context for _rcuidle tracepoints (again) Message-ID: <20200219174025.GJ2935@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200219144724.800607165@infradead.org> <20200219150745.125119627@infradead.org> <20200219164356.GB2935@paulmck-ThinkPad-P72> <20200219164736.GL18400@hirez.programming.kicks-ass.net> <20200219170507.GH14946@hirez.programming.kicks-ass.net> <20200219122116.7aeaf230@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200219122116.7aeaf230@gandalf.local.home> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 19, 2020 at 12:21:16PM -0500, Steven Rostedt wrote: > On Wed, 19 Feb 2020 18:05:07 +0100 > Peter Zijlstra wrote: > > > On Wed, Feb 19, 2020 at 05:47:36PM +0100, Peter Zijlstra wrote: > > > On Wed, Feb 19, 2020 at 08:43:56AM -0800, Paul E. McKenney wrote: > > > > On Wed, Feb 19, 2020 at 03:47:37PM +0100, Peter Zijlstra wrote: > > > > > Effectively revert commit 865e63b04e9b2 ("tracing: Add back in > > > > > rcu_irq_enter/exit_irqson() for rcuidle tracepoints") now that we've > > > > > taught perf how to deal with not having an RCU context provided. > > > > > > > > > > Signed-off-by: Peter Zijlstra (Intel) > > > > > --- > > > > > include/linux/tracepoint.h | 8 ++------ > > > > > 1 file changed, 2 insertions(+), 6 deletions(-) > > > > > > > > > > --- a/include/linux/tracepoint.h > > > > > +++ b/include/linux/tracepoint.h > > > > > @@ -179,10 +179,8 @@ static inline struct tracepoint *tracepo > > > > > > > > Shouldn't we also get rid of this line above? > > > > > > > > int __maybe_unused __idx = 0; \ > > > > > > > > > > Probably makes a lot of sense, lemme fix that! > > > > Oh wait, no! SRCU is the one that remains ! > > Correct, and if rcuidle is not set, and this is a macro, the SRCU > portion is compiled out. Sigh! Apologies for the noise! If we are using SRCU, we don't care whether or not RCU is watching. OK, maybe finally catching up -- the whole point was use of RCU in other tracing code, wasn't it? Thanx, Paul