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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C311DC433FE for ; Fri, 22 Apr 2022 15:52:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1449578AbiDVPze (ORCPT ); Fri, 22 Apr 2022 11:55:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355262AbiDVPzc (ORCPT ); Fri, 22 Apr 2022 11:55:32 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42D8D18388; Fri, 22 Apr 2022 08:52:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 03CE8B8311D; Fri, 22 Apr 2022 15:52:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A07EBC385A0; Fri, 22 Apr 2022 15:52:35 +0000 (UTC) Date: Fri, 22 Apr 2022 11:52:34 -0400 From: Steven Rostedt To: patrick wang Cc: paulmck@kernel.org, frederic@kernel.org, quic_neeraju@quicinc.com, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, joel@joelfernandes.org, rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] rcu: ftrace: avoid tracing a few functions executed in multi_cpu_stop() Message-ID: <20220422115234.613436e4@gandalf.local.home> In-Reply-To: References: <20220418043735.11441-1-patrick.wang.shcn@gmail.com> <20220418143404.55c8fcab@gandalf.local.home> <20220420114454.69ab108c@gandalf.local.home> <20220420122633.55d4ff6b@gandalf.local.home> <20220421085047.2cb8edf9@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 22 Apr 2022 18:45:46 +0800 patrick wang wrote: > Yes, and not just RISC-V. It's arch-independent. It's the internal change of > stop machine implementation. > > ---------------------------------------------------------------- > Former stop machine wait loop: > do { > cpu_relax(); => macro > ... > } while (curstate != STOPMACHINE_EXIT); > ----------------------------------------------------------------- > Current stop machine wait loop: > do { > stop_machine_yield(cpumask); => function (notraced) > ... > touch_nmi_watchdog(); => function (notraced, inside calls also notraced) > ... > rcu_momentary_dyntick_idle(); => function (notraced, inside calls traced) > } while (curstate != MULTI_STOP_EXIT); > ------------------------------------------------------------------ That makes much more sense. Can you add that to the change log. Reviewed-by: Steven Rostedt (Google) -- Steve