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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 29358C34056 for ; Wed, 19 Feb 2020 19:05:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5F9F24671 for ; Wed, 19 Feb 2020 19:05:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582139124; bh=a8v8o/RLgXbtSPWW2aaagFCiOmMgfZKdTuyS8Lp1V+8=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=jEdXsrNAutzlfUXQH20uxMUNqywaxo6OLRdLDmUj8TZdbTmgDfomFCBKXTTcpI2S9 xtnSq4p8z4e5FbUP68e7cbQreVCadqlsn6MpKEowA83IpkK5bky8WuL7vj0TJ1GJe0 KeMzLRW3U/iua6uyJZhVN5YgCghlWYaR/237DypQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726750AbgBSTFW (ORCPT ); Wed, 19 Feb 2020 14:05:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:41706 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726613AbgBSTFW (ORCPT ); Wed, 19 Feb 2020 14:05:22 -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 025C624654; Wed, 19 Feb 2020 19:05:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582139122; bh=a8v8o/RLgXbtSPWW2aaagFCiOmMgfZKdTuyS8Lp1V+8=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=aoKhVjpyyOdq2W0Mcocjnqb+Ff8EeI0eZ2hOC84yrZTmvSpFNnA6UWbKVu2QtjC48 xcm/bJycVQnY8Yewh/mwYYPiiXBF6eCgEfdgrAepABeWgp8/BosEa+FVsTAorMv/4p 9i8cE787xpfvfTYv29SzApEvz0/xZah1hbKFDT5Y= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id D2D903520BB6; Wed, 19 Feb 2020 11:05:21 -0800 (PST) Date: Wed, 19 Feb 2020 11:05:21 -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: <20200219190521.GO2935@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> <20200219174025.GJ2935@paulmck-ThinkPad-P72> <20200219130012.116670fd@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200219130012.116670fd@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 01:00:12PM -0500, Steven Rostedt wrote: > On Wed, 19 Feb 2020 09:40:25 -0800 > "Paul E. McKenney" wrote: > > > > 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? > > Some callbacks (namely perf) might use RCU, but then the callbacks > need to make sure rcu is watching. Got it, thank you! Thanx, Paul