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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 308F3C433E0 for ; Mon, 8 Feb 2021 14:51:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E66D964E27 for ; Mon, 8 Feb 2021 14:51:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232929AbhBHOvT (ORCPT ); Mon, 8 Feb 2021 09:51:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232805AbhBHOqn (ORCPT ); Mon, 8 Feb 2021 09:46:43 -0500 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9A25C061786; Mon, 8 Feb 2021 06:46:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ezjM9RK8q9ZkDU1hNSWqUp0BpKofzQPgjLv9MoG7YR4=; b=K4Z/FZ84HTnviv3KOinJCLCc2E Nd2m71fWtpnBotID/OaFotnIvBm0AKd1GEn1vvGk6E6rVTCQP9WU8h8jdrwGFLS4tTJvmWvg3CDdZ l1BAY3T6RS6vFIeaILq7ONb9Yn1Rwlp2rxP4zjt+9/xt0QYWaENveK/k2CWvAbCWIQnEzxgRXYAsT Tbe9lGZ74EIYG4XFAtyn35C3kFX9N+5S6MB7ZUGkpX1KofxOILj3GBjtmn8jj9xApocKZ/iRyWQW6 LjwCAoFtgDyL1DACAOTucmlsSx3yxSly3ujl836DHjxcT+P7khvOFmThucPXRx0sm32kmN9UiHKwj OIYimmcg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1l97nX-0001A9-7H; Mon, 08 Feb 2021 14:45:55 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 943DA3010D2; Mon, 8 Feb 2021 15:45:50 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 57DF22BF5C9B6; Mon, 8 Feb 2021 15:45:50 +0100 (CET) Date: Mon, 8 Feb 2021 15:45:50 +0100 From: Peter Zijlstra To: Frederic Weisbecker Cc: "Paul E . McKenney" , LKML , Paolo Bonzini , "Rafael J . Wysocki" , Thomas Gleixner , stable@vger.kernel.org, Ingo Molnar Subject: Re: [PATCH 2/5] rcu/nocb: Perform deferred wake up before last idle's need_resched() check Message-ID: References: <20210131230548.32970-1-frederic@kernel.org> <20210131230548.32970-3-frederic@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210131230548.32970-3-frederic@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 01, 2021 at 12:05:45AM +0100, Frederic Weisbecker wrote: > diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c > index 305727ea0677..b601a3aa2152 100644 > --- a/kernel/sched/idle.c > +++ b/kernel/sched/idle.c > @@ -55,6 +55,7 @@ __setup("hlt", cpu_idle_nopoll_setup); > static noinline int __cpuidle cpu_idle_poll(void) > { > trace_cpu_idle(0, smp_processor_id()); > + rcu_nocb_flush_deferred_wakeup(); > stop_critical_timings(); > rcu_idle_enter(); > local_irq_enable(); > @@ -173,6 +174,8 @@ static void cpuidle_idle_call(void) > struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); > int next_state, entered_state; > > + rcu_nocb_flush_deferred_wakeup(); > + > /* > * Check if the idle task must be rescheduled. If it is the > * case, exit the function after re-enabling the local irq. Ok if I do this instead? --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -55,7 +55,6 @@ __setup("hlt", cpu_idle_nopoll_setup); static noinline int __cpuidle cpu_idle_poll(void) { trace_cpu_idle(0, smp_processor_id()); - rcu_nocb_flush_deferred_wakeup(); stop_critical_timings(); rcu_idle_enter(); local_irq_enable(); @@ -174,8 +173,6 @@ static void cpuidle_idle_call(void) struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); int next_state, entered_state; - rcu_nocb_flush_deferred_wakeup(); - /* * Check if the idle task must be rescheduled. If it is the * case, exit the function after re-enabling the local irq. @@ -288,6 +285,7 @@ static void do_idle(void) } arch_cpu_idle_enter(); + rcu_nocb_flush_deferred_wakeup(); /* * In poll mode we reenable interrupts and spin. Also if we