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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8DFB1C001B0 for ; Thu, 10 Aug 2023 08:04:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232927AbjHJIEM (ORCPT ); Thu, 10 Aug 2023 04:04:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232535AbjHJIEK (ORCPT ); Thu, 10 Aug 2023 04:04:10 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5EF1F7 for ; Thu, 10 Aug 2023 01:03:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691654606; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PfaC/PDyoa2b4RxaoBt6Mltx+tgnoVJUP3gprplX2qg=; b=a10gpJHd4L32jgjOkdIO2jrkIi3dg8HRfQylueUrKlNss3Az+aGthejTBBbmjLzZoqf2NH XruuVL3z1j1F5ejqV6afHaAgbwqSrzDfCnAdZlr3geROfL+4ezYI9IKfyrMjwxz8w9CNdI Kx5F201RlreKqEN91/5MR5lS8iGs/Rc= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-274-VeceugrkPlKE_59SnbY3xQ-1; Thu, 10 Aug 2023 04:03:24 -0400 X-MC-Unique: VeceugrkPlKE_59SnbY3xQ-1 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-3fc07d4c63eso8001495e9.1 for ; Thu, 10 Aug 2023 01:03:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691654603; x=1692259403; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=PfaC/PDyoa2b4RxaoBt6Mltx+tgnoVJUP3gprplX2qg=; b=TdW4D53ei7dBNJTzQmPHsWMl9HgHtE5e22sRc3JLC7hT0MTDttgqHrc3zsCZBtF7zc P6ek+GSyZFxSHk8AO1dj8IQsqWaTxwecTaCSWpsGdORvgxl7HkMwOZI1hp83kxqDQVbi ZF2rpCAb+S1D+5p2datMiY/RKlX/83f2FIsjXg0hT+Z4dDmJxbuPtjCfJnoR2POweo9j RFYU1SWklXWht8OcX9tWqNtp1HM2q2SOt5cQ1EdZ2inKOxTzzZUtkcXefU4aijUWAnug hQHsFMBNFhbGXjdPlLNBMLvVISs9AjsVCcSawx/TDKjXAPOYYJb4YxConvGC6PU0nkCk Przg== X-Gm-Message-State: AOJu0YyOupWUsIG6cDxvnl9zHSq+UEFdOFlnC8mfuvJfYCVKUng4oawZ Yrwb2M3+APFLe5xmm3UQUdFwpb7jHu3iQ6l8IetR29Ag65wmE/dp0r6UeUyI+hFYmAVWpPmdkkK 8jsJl78h/SQRHOI7pI2zlBIuXujjvOSzfYbCzk7v/VU/oPqvOvLK8/DmR5J3ewTztb83/gn984E QGbVJ/4Udj X-Received: by 2002:a7b:ce8b:0:b0:3fd:2e87:aa28 with SMTP id q11-20020a7bce8b000000b003fd2e87aa28mr1011876wmj.15.1691654603441; Thu, 10 Aug 2023 01:03:23 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFCX7iSjniJWsvTWd6ph7Eo1eCX+q/cocqk5NHK/Qs7MLihsJbpvXao4p9dyhd+I6r++cho+Q== X-Received: by 2002:a7b:ce8b:0:b0:3fd:2e87:aa28 with SMTP id q11-20020a7bce8b000000b003fd2e87aa28mr1011838wmj.15.1691654602816; Thu, 10 Aug 2023 01:03:22 -0700 (PDT) Received: from vschneid.remote.csb ([93.186.150.163]) by smtp.gmail.com with ESMTPSA id v22-20020a1cf716000000b003fe23b10fdfsm4260371wmh.36.2023.08.10.01.03.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Aug 2023 01:03:22 -0700 (PDT) From: Valentin Schneider To: Peter Zijlstra Cc: mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/9] sched: Simplify ttwu() In-Reply-To: <20230809192651.GU212435@hirez.programming.kicks-ass.net> References: <20230801204121.929256934@infradead.org> <20230801211812.101069260@infradead.org> <20230809192651.GU212435@hirez.programming.kicks-ass.net> Date: Thu, 10 Aug 2023 09:03:21 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/08/23 21:26, Peter Zijlstra wrote: > On Wed, Aug 09, 2023 at 04:21:36PM +0100, Valentin Schneider wrote: >> On 01/08/23 22:41, Peter Zijlstra wrote: >> > Use guards to reduce gotos and simplify control flow. >> > >> > Signed-off-by: Peter Zijlstra (Intel) >> > --- >> > kernel/sched/core.c | 221 +++++++++++++++++++++++++--------------------------- >> > 1 file changed, 109 insertions(+), 112 deletions(-) >> > >> > --- a/kernel/sched/core.c >> > +++ b/kernel/sched/core.c >> > @@ -3706,14 +3706,14 @@ ttwu_stat(struct task_struct *p, int cpu >> > struct sched_domain *sd; >> > >> > __schedstat_inc(p->stats.nr_wakeups_remote); >> > - rcu_read_lock(); >> > + >> > + guard(rcu)(); >> >> This isn't strictly equivalent, right? AFAICT that pushes the >> rcu_read_unlock() further down than it currently is - not a big deal, but >> indentation aside scoped_guard() would preserve that. > > The full hunk: > > | @@ -3706,14 +3706,14 @@ ttwu_stat(struct task_struct *p, int cpu > | struct sched_domain *sd; > | > | __schedstat_inc(p->stats.nr_wakeups_remote); > | - rcu_read_lock(); > | + > | + guard(rcu)(); > | for_each_domain(rq->cpu, sd) { > | if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { > | __schedstat_inc(sd->ttwu_wake_remote); > | break; > | } > | } > | - rcu_read_unlock(); > | } > > And you'll see the guard goes out of scope here ^ > > Which is the exact place rcu_read_unlock() was at, no? Bleh, yes, lost track of the scope there...