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=-9.8 required=3.0 tests=BAYES_00,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=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 58352C4727C for ; Fri, 25 Sep 2020 15:29:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 247EA23772 for ; Fri, 25 Sep 2020 15:29:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601047750; bh=rOVcj/V35cyfMa0Vlg8hucdK+66n/l/bpxjyII5KeJ0=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=FtKafBIul3eIKR12ww2guveFGDN6Gmbb66+pJFf96GoNtzGBt4ysMvyunr6BsfDwp ySv0cgaqFn16H6l8eilu4UBCl5pHsskTEiujmAeCrlMgxisBHpVLVj/D+6cSY1iYp4 tQtb3wi98261qA+Vmg6woRkTiHv3dk4rmPzCqnwA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729204AbgIYP3G (ORCPT ); Fri, 25 Sep 2020 11:29:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:56948 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728612AbgIYP3G (ORCPT ); Fri, 25 Sep 2020 11:29:06 -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 D2B10235F9; Fri, 25 Sep 2020 15:29:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601047745; bh=rOVcj/V35cyfMa0Vlg8hucdK+66n/l/bpxjyII5KeJ0=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=twt0N8Abp9/Po1t9micl7QeynkbSKIgF9pG47HY5rYmOCvHWpfcRB8LlA0LlSnx9V g+4xPB19lcoxmjeyuhvrwqjDXjp5yJ++pbQ6b/b92WxI4prVpFXhmQze82tVUECRxY cC5FYO6TCIx4vwuYHKIuzmxdED0g6N13t8dQuh9M= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 98E1035207C1; Fri, 25 Sep 2020 08:29:05 -0700 (PDT) Date: Fri, 25 Sep 2020 08:29:05 -0700 From: "Paul E. McKenney" To: Guenter Roeck Cc: Peter Zijlstra , rjw@rjwysocki.net, bp@alien8.de, 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 Subject: Re: [RFC][PATCH 4/4] acpi: Take over RCU-idle for C3-BM idle Message-ID: <20200925152905.GE29330@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200915103157.345404192@infradead.org> <20200915103806.479637218@infradead.org> <20200925152000.GA171076@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200925152000.GA171076@roeck-us.net> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri, Sep 25, 2020 at 08:20:00AM -0700, Guenter Roeck wrote: > On Tue, Sep 15, 2020 at 12:32:01PM +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) > > ia64:defconfig: > > ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined! > ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined! > > I realize that this has already been reported more than a week ago, with > no visible reaction. Another problem introduced in the same file, resulting > in > > drivers/acpi/processor_idle.c: In function 'lapic_timer_needs_broadcast': > drivers/acpi/processor_idle.c:179:1: warning: > no return statement in function returning non-void > > may cause ia64 boot problems since a non-zero return value will trigger > a function call. AFAICS that is not supposed to happen on ia64. > > This makes me wonder - if no one cares about buiding (much less running) > ia64 images with the upstream kernel, is it possibly time to remove it ? Rafael is taking a fix up his cpuidle tree: https://lkml.kernel.org/lkml/CAJZ5v0jVerU92WxL4qCoU6NC0KCyszmRNhpL3tu5LYtMqALd9A@mail.gmail.com/ Thanx, Paul