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=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 CF965C433E0 for ; Fri, 24 Jul 2020 17:55:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A286F206D8 for ; Fri, 24 Jul 2020 17:55:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595613344; bh=abI4X26iEEWTuAT3rk/GC6BYj68hu/Mf/vonXod3ZX8=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:List-ID: From; b=LRSL3vyXYFtdgIcfepCKdUSdOnJTr1vUt/NnFIMRbolecATOHyrj6/htWlRHMjvv3 gOBYBbUaTT8gzfjt/1H6v2DFK9ZS470U9ymVgBw6N02N9TC4ITmvaGBZ0HJh6Pa2Uf 9yZTOXt6AOInbNszZEaK2ALpCNZiSSBp3wHy8vIY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726901AbgGXRzn (ORCPT ); Fri, 24 Jul 2020 13:55:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:54542 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726617AbgGXRzn (ORCPT ); Fri, 24 Jul 2020 13:55:43 -0400 Received: from paulmck-ThinkPad-P72.home (50-39-111-31.bvtn.or.frontiernet.net [50.39.111.31]) (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 9CB412067D; Fri, 24 Jul 2020 17:55:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595613342; bh=abI4X26iEEWTuAT3rk/GC6BYj68hu/Mf/vonXod3ZX8=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=xQlMO60SBY639JcTLwHYXZeM5+/IYps1cTQWGBWp1Xihee50QYuHXYxBk7WS4bYq3 xfzH4SFK8H4SHjeLFa0XcyX5a8SAFu345orVNMPwee0XBTGT8GDK/hW9I6rLT/oGZo Pzy7KIhZtJyZ1YaFlHu7aDWnLLaWfaCoeoE1jNus= Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id 8A38C3520BD1; Fri, 24 Jul 2020 10:55:42 -0700 (PDT) Date: Fri, 24 Jul 2020 10:55:42 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: Chris Wilson , mingo@kernel.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, frederic@kernel.org, torvalds@linux-foundation.org, hch@lst.de Subject: Re: [PATCH -v2 1/5] sched: Fix ttwu() race Message-ID: <20200724175542.GR9247@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20200622100122.477087977@infradead.org> <20200622100825.726200103@infradead.org> <159532854586.15672.5123219635720172265@build.alporthouse.com> <20200721113719.GI119549@hirez.programming.kicks-ass.net> <159541187604.15672.2433896906671712337@build.alporthouse.com> <20200723182841.GS10769@hirez.programming.kicks-ass.net> <159553326368.21069.3167204000119437062@build.alporthouse.com> <20200723201128.GT10769@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200723201128.GT10769@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 23, 2020 at 10:11:28PM +0200, Peter Zijlstra wrote: > On Thu, Jul 23, 2020 at 08:41:03PM +0100, Chris Wilson wrote: > > > I am very sorry for the wild goose chase. > > *phew*... all good then. I was starting to go a little ga-ga trying to > make sense of things. > > Arguably we should probably do something like: > > > @@ -4555,7 +4572,7 @@ asmlinkage __visible void __sched preempt_schedule_irq(void) > int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags, > void *key) > { > - return try_to_wake_up(curr->private, mode, wake_flags); > + return try_to_wake_up(curr->private, mode, wake_flags & WF_SYNC); > } > EXPORT_SYMBOL(default_wake_function); If you do: Tested-by: Paul E. McKenney This was about nine hours of each of the default rcutorture scenarios. Thanx, Paul > Since I don't think anybody uses anything other than WF_SYNC, ever. And > the rest of the WF_flags are used internally. > > Thanks Chris!