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=-13.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 CC847C433E3 for ; Fri, 7 Aug 2020 17:08:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 95061221E5 for ; Fri, 7 Aug 2020 17:08:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="Q/KGFW4z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726094AbgHGRI1 (ORCPT ); Fri, 7 Aug 2020 13:08:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726823AbgHGRHb (ORCPT ); Fri, 7 Aug 2020 13:07:31 -0400 Received: from mail-qt1-x843.google.com (mail-qt1-x843.google.com [IPv6:2607:f8b0:4864:20::843]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09E32C061A2B for ; Fri, 7 Aug 2020 10:07:31 -0700 (PDT) Received: by mail-qt1-x843.google.com with SMTP id s16so1785119qtn.7 for ; Fri, 07 Aug 2020 10:07:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=DWbloqsrP0AQsrj6SmmxzbX/ZWsrIvuOIBVWCascTtc=; b=Q/KGFW4zhhUvta6vR2CwSlNmcirLLQgN1UHKs1PAFMVRyM5AmvjqxtwQuc7zhSovGO ly9olFSHeHS0YAa+ZOraTOjnV5sE16p3X03nyz5uOiIugMnTcjuCsf9fkLhGjwlnByxU WJ4Zmlf/GRbSE4zEj22vV00mE/cMixdWHS0Z8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=DWbloqsrP0AQsrj6SmmxzbX/ZWsrIvuOIBVWCascTtc=; b=l39c+k7IEbmu0ZjeL6semgrEuh1dvK4BCvScq+LFBDE+uWJiSm1aPYkT1jnrOTUg+v EyBYWxo7egZTAG4NYFA9zP64xM3XkKvq59JsFlpXHKq4PWpGQzVGjqLqM55Q4fVfNwWF bzAanXQaC6yj6+Xq6B5b+ZQ39TVWp8DGMTsKF1UFP7eZwRJ+2wipd7Kmi9ngKdZVV1+9 fKfNAp63KcyX24rV6+iYWkrdtgnUTSEL3KH+1puagm+gqICYWYYgMyp/g20SmPqFGxJr 9F7Q/LmiC8NWOHGGbhNqX+eox5SOZEUgI6Xn6JK4ywt3LmgIn8u36daktwZsRxTvD7YG MnmA== X-Gm-Message-State: AOAM532Pd9wTSJCC2nQgj7gBc/8Cn6z0pJ/Yezbt4txv5P/CVpJdJwxB 6mAt+CEdJUKiLEqAZ4gQEwLJ3w== X-Google-Smtp-Source: ABdhPJx3f6sCntEP3jmyqzNa+3yifVW0H++FgQSlZMWDjMxxvQUVR4wb+sfKmy+A4/cj+TLqN0mOkQ== X-Received: by 2002:ac8:45c3:: with SMTP id e3mr5903192qto.149.1596820050230; Fri, 07 Aug 2020 10:07:30 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:cad3:ffff:feb3:bd59]) by smtp.gmail.com with ESMTPSA id w18sm8559905qtk.1.2020.08.07.10.07.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Aug 2020 10:07:29 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , Davidlohr Bueso , Jonathan Corbet , Josh Triplett , Lai Jiangshan , linux-doc@vger.kernel.org, Mathieu Desnoyers , Mauro Carvalho Chehab , neeraju@codeaurora.org, "Paul E. McKenney" , peterz@infradead.org, Randy Dunlap , rcu@vger.kernel.org, Steven Rostedt , tglx@linutronix.de, vineethrp@gmail.com Subject: [PATCH v4 2/5] rcu/tree: Clarify comments about FQS loop reporting quiescent states Date: Fri, 7 Aug 2020 13:07:19 -0400 Message-Id: <20200807170722.2897328-3-joel@joelfernandes.org> X-Mailer: git-send-email 2.28.0.236.gb10cc79966-goog In-Reply-To: <20200807170722.2897328-1-joel@joelfernandes.org> References: <20200807170722.2897328-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org At least since v4.19, the FQS loop no longer reports quiescent states for offline CPUs unless it is an emergency. This commit therefore fixes the comment in rcu_gp_init() to match the current code. Signed-off-by: Joel Fernandes (Google) --- kernel/rcu/tree.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index a49fa3b60faa..2fb66cdbfa25 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1701,9 +1701,11 @@ static bool rcu_gp_init(void) /* * Apply per-leaf buffered online and offline operations to the - * rcu_node tree. Note that this new grace period need not wait - * for subsequent online CPUs, and that quiescent-state forcing - * will handle subsequent offline CPUs. + * rcu_node tree. Note that this new grace period need not wait for + * subsequent online CPUs, and that RCU hooks in the CPU offlining + * path, when combined with checks in this function, will handle CPUs + * that are currently going offline or that go offline later. Refer to + * RCU's Requirements documentation about hotplug requirements as well. */ rcu_state.gp_state = RCU_GP_ONOFF; rcu_for_each_leaf_node(rnp) { -- 2.28.0.236.gb10cc79966-goog