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=-8.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 DBB34C4363D for ; Fri, 25 Sep 2020 15:20:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 90CC421D42 for ; Fri, 25 Sep 2020 15:20:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bkype4lD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728858AbgIYPUE (ORCPT ); Fri, 25 Sep 2020 11:20:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728654AbgIYPUE (ORCPT ); Fri, 25 Sep 2020 11:20:04 -0400 Received: from mail-oi1-x243.google.com (mail-oi1-x243.google.com [IPv6:2607:f8b0:4864:20::243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 065A5C0613CE; Fri, 25 Sep 2020 08:20:04 -0700 (PDT) Received: by mail-oi1-x243.google.com with SMTP id u126so3099630oif.13; Fri, 25 Sep 2020 08:20:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=OAz96dzZAfm+2IsbvC6/JC7wz7Vim1MaFIU86o+xxBc=; b=bkype4lDtQu8pRj6WfmiXQPUW+sj2sSQKx24pH0BxTPiqKHNS4T2ysAtgj+b95adKv f0L49bmor4OFG/JEmdpiZoQRV2z/NK6jrngYQaHjcUXP2UcNxfbeinh6US+vEw2towrz KId04bKS0LtZQ7nIEeSlSuzKskFQhQKpav35kZmiRQ17cdS7Ih5vE8XjQc/YuYFmpQSs rfJbRuNGZ1ZSLYwRC+HyMQQYRNejMaTFg47BzoM5MuWtIcQXHh9mB1C5XQaz57lVnzxG M2XJdtUBa3/4op50EiwxaBJf5tHBlPFl1dbXT3hISOPJ7HG77WS0gt3Cb4tDEvjSdptY 8fOw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=OAz96dzZAfm+2IsbvC6/JC7wz7Vim1MaFIU86o+xxBc=; b=YLNDy5kEisgKXDbXGI5VSUmZ2QWEV2Rb+ltHxjuRI5WIgUH8iwXhxebIuWE2uI4/Hd MRkPrlHWXAQrDBi3xab+3aTfZVkhjlsEv2hQ2VprvmEQXDZo7ypchTR51wDYGoM5fTGU NDTUJhQh8wcdNC6YiQ4sZwfezwLtR2M+vM/R5p307Gt2UDPB8N3y+P8duyLPehfaVHxo 1+iCH1+/L051hppUCalBbFLMWpaxNV6Ac0CvqQ/9Fcqn3gbhbYtsZvNP0iVviSoQTUqk GBEQDp9QKrjfUZpru+UsJtFaLjne5oMzj424pXfhIbTE0l7WcnSune1c18q1kJL2lt+y D5Dg== X-Gm-Message-State: AOAM531y2yGLiDEFQrx7VUn/CoO830ReLgRtYRaW6dT3kd/qlf4JWL5d v3nZv5sCwwnQIQgAuqhkrPY= X-Google-Smtp-Source: ABdhPJxr625Iuk10y+rqyxSf4pr0wUa75eDXBc27X9CAnPokzupWPQnmgPcYyJ2e+9oCEnyjzADR1A== X-Received: by 2002:a05:6808:a05:: with SMTP id n5mr566305oij.154.1601047203447; Fri, 25 Sep 2020 08:20:03 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id g22sm709668ots.35.2020.09.25.08.20.01 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Fri, 25 Sep 2020 08:20:02 -0700 (PDT) Sender: Guenter Roeck Date: Fri, 25 Sep 2020 08:20:00 -0700 From: Guenter Roeck To: Peter Zijlstra Cc: 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, paulmck@kernel.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: <20200925152000.GA171076@roeck-us.net> References: <20200915103157.345404192@infradead.org> <20200915103806.479637218@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200915103806.479637218@infradead.org> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org 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 ? Guenter