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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 63CBEC43469 for ; Mon, 21 Sep 2020 13:32:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D01D206A2 for ; Mon, 21 Sep 2020 13:32:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600695163; bh=QNhlBi6lTl9xfjIdbg7JvRCpeE5h4ZjLWJuKLQlH/GE=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=QzqldUyj+5qIRZsuzpIIgH6mOQ0Ksaupr7+yCNm1atdfQ5mftUv71vzxw61wj5rSU 2RZDj4Yh+SZPwl/Eg2lsZZlpcplZwqF6pjMTjQXumkSSdwxxr840/k/hJFu2d95SMD kNzl6a1+BWae43I5omh7XM1gWWD3YcuLe/Nr5t4A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726690AbgIUNcm (ORCPT ); Mon, 21 Sep 2020 09:32:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:52140 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726496AbgIUNcm (ORCPT ); Mon, 21 Sep 2020 09:32:42 -0400 Received: from paulmck-ThinkPad-P72.home (unknown [50.45.173.55]) (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 C8F62207C3; Mon, 21 Sep 2020 13:32:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600695161; bh=QNhlBi6lTl9xfjIdbg7JvRCpeE5h4ZjLWJuKLQlH/GE=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=wicSCh3ti1lEJiKfhwM/KyC5vBSp+hnNEp/ZdjauWZqEC7xSJNMmoh5Ug1DmBtXsJ 2org7picp45q5FxUzyuWOlJNbFoC5mocge2bzQv4X8Uy7fVl6wEnBnNbz3rMtruWUr OgzHmLO5//z0YiCwV6YWfuybB+qbXGSZwZ4mESw4= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 8B60E35227BD; Mon, 21 Sep 2020 06:32:41 -0700 (PDT) Date: Mon, 21 Sep 2020 06:32:41 -0700 From: "Paul E. McKenney" To: Borislav Petkov Cc: Sven Joachim , Peter Zijlstra , rjw@rjwysocki.net, x86@kernel.org, tony.luck@intel.com, lenb@kernel.org, daniel.lezcano@linaro.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, ulf.hansson@linaro.org, tglx@linutronix.de, naresh.kamboju@linaro.org, Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , rcu@vger.kernel.org Subject: Re: [PATCH] rcu/tree: Export rcu_idle_{enter,exit} to module Message-ID: <20200921133241.GB29330@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200915103157.345404192@infradead.org> <20200915103806.479637218@infradead.org> <87wo0npk72.fsf@turtle.gmx.de> <20200921103741.GC5901@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200921103741.GC5901@zn.tnic> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Mon, Sep 21, 2020 at 12:37:41PM +0200, Borislav Petkov wrote: > Lemme add whatever get_maintainer spits, to Cc. > > On Mon, Sep 21, 2020 at 11:12:33AM +0200, Sven Joachim wrote: > > On 2020-09-15 12:32 +0200, Peter Zijlstra wrote: > > > > > The C3 BusMaster idle code takes lock in a number of places, some deep > > > inside the ACPI code. Instead of wrapping it all in RCU_NONIDLE, have > > > the driver take over RCU-idle duty and avoid flipping RCU state back > > > and forth a lot. > > > > > > ( by marking 'C3 && bm_check' as RCU_IDLE, we _must_ call enter_bm() for > > > that combination, otherwise we'll loose RCU-idle, this requires > > > shuffling some code around ) > > > > > > Signed-off-by: Peter Zijlstra (Intel) > > > > I got modpost errors in 5.9-rc6 after this patch: > > > > ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined! > > ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined! > > > > Reverting commit 1fecfdbb7acc made them go away. Notably my > > configuration had CONFIG_ACPI_PROCESSOR=m, changing that > > to CONFIG_ACPI_PROCESSOR=y let the build succeed as well. > > I guess this. Running randconfigs on it for a while, to see what else > breaks. > > --- > From: Borislav Petkov > Date: Mon, 21 Sep 2020 12:31:36 +0200 > > Fix this link error: > > ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined! > ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined! > > when CONFIG_ACPI_PROCESSOR is built as module. PeterZ says that in light > of ARM needing those soon too, they should simply be exported. > > Fixes: 1fecfdbb7acc ("ACPI: processor: Take over RCU-idle for C3-BM idle") > Reported-by: Sven Joachim > Suggested-by: Peter Zijlstra > Signed-off-by: Borislav Petkov Reviewed-by: Paul E. McKenney > --- > kernel/rcu/tree.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index 8ce77d9ac716..f78ee759af9c 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -673,6 +673,7 @@ void rcu_idle_enter(void) > lockdep_assert_irqs_disabled(); > rcu_eqs_enter(false); > } > +EXPORT_SYMBOL_GPL(rcu_idle_enter); > > #ifdef CONFIG_NO_HZ_FULL > /** > @@ -886,6 +887,7 @@ void rcu_idle_exit(void) > rcu_eqs_exit(false); > local_irq_restore(flags); > } > +EXPORT_SYMBOL_GPL(rcu_idle_exit); > > #ifdef CONFIG_NO_HZ_FULL > /** > -- > 2.21.0 > > -- > Regards/Gruss, > Boris. > > https://people.kernel.org/tglx/notes-about-netiquette