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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 DA633C65BD0 for ; Fri, 5 Oct 2018 23:18:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A1573206B2 for ; Fri, 5 Oct 2018 23:18:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="XjhtMzt5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1573206B2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joelfernandes.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729226AbeJFGT1 (ORCPT ); Sat, 6 Oct 2018 02:19:27 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:41780 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729070AbeJFGT0 (ORCPT ); Sat, 6 Oct 2018 02:19:26 -0400 Received: by mail-pf1-f193.google.com with SMTP id m77-v6so5730927pfi.8 for ; Fri, 05 Oct 2018 16:18:32 -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=YA9WH3pfYU6schmD91/Hmd5hK9+CpUcqh3SP6wwSGRA=; b=XjhtMzt5Xd6fiPGeYST7XCyh8L60eEuk07+Hm95TeHuDpkYIsD45rr9NBSEd1Vi3It MhUw3JiOoIlGryCXOsgG6KK1GMC82uGIEOXSioQPmpQ5DCvZekWkQXGCY/sshKPyc1Fy Jnz4p3xlqd6fxMP4BwhyEdI7g7e/zeGcdvTz8= 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=YA9WH3pfYU6schmD91/Hmd5hK9+CpUcqh3SP6wwSGRA=; b=Mb9EIt65uIIB/Seec7G1RW5GY+9VQEKaMK/pfxR2H+UF5XxIVmFo2zs7ZsBgviZIDQ fWbs/rDfsI8JcKQCcqqPKhf/EJYcy1M6Q1dbeFiK0ES+4UHUwTywvCj8yHtq+HQwiiNJ s0uj5IINpAyuq3Z+xacUAMIlxYBSB3vacgyoQ9wHSG4jt0OqPMfCDxZcfELTbqkB3Rrs rjlTYtTDfNTboxrf1iv4XzFLJoHWeG/RHxDE7m8fMzcndAO03RT0KE8jrDzHupTJfZwO EZ87Jfh9ii53NKB8h4dt0R98ZVkbhphPnfJZ9czbhJKdOY2vxHOaDKTxba6BGUDP/A+r kN2g== X-Gm-Message-State: ABuFfoii73vxchVK2uQEwXk2l06U6rT8P8KQVSkw5TeAdFqOpTua38rc cqndTaU7mHFVPyPC2iA+4iJNcjdirmA= X-Google-Smtp-Source: ACcGV621aXYCsucSyU0/Rh3IRnWXf4FMAI2g+LOkygUhhZsXWSi62pyIDHV8XrImCLt/6bsfYRC8hQ== X-Received: by 2002:a63:608c:: with SMTP id u134-v6mr11850262pgb.266.1538781511252; Fri, 05 Oct 2018 16:18:31 -0700 (PDT) Received: from joelaf.mtv.corp.google.com ([2620:0:1000:1601:3aef:314f:b9ea:889f]) by smtp.gmail.com with ESMTPSA id q76-v6sm16641028pfa.18.2018.10.05.16.18.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 05 Oct 2018 16:18:29 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , Jonathan Corbet , Josh Triplett , Lai Jiangshan , linux-doc@vger.kernel.org, Mathieu Desnoyers , "Paul E. McKenney" , Steven Rostedt , pantin@google.com Subject: [PATCH RFC 2/5] doc: rcu: Add more rationale for using rcu_read_lock_sched in checklist Date: Fri, 5 Oct 2018 16:18:11 -0700 Message-Id: <20181005231815.170433-3-joel@joelfernandes.org> X-Mailer: git-send-email 2.19.0.605.g01d371f741-goog In-Reply-To: <20181005231815.170433-1-joel@joelfernandes.org> References: <20181005231815.170433-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It could be clarified better why rcu_read_lock_sched is better than using preempt_disable, add the same. Signed-off-by: Joel Fernandes (Google) --- Documentation/RCU/checklist.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt index 49747717d905..8860ab2a897a 100644 --- a/Documentation/RCU/checklist.txt +++ b/Documentation/RCU/checklist.txt @@ -63,7 +63,7 @@ over a rather long period of time, but improvements are always welcome! pointer must be covered by rcu_read_lock(), rcu_read_lock_bh(), rcu_read_lock_sched(), or by the appropriate update-side lock. Disabling of preemption can serve as rcu_read_lock_sched(), but - is less readable. + is less readable and prevents lockdep from detecting locking issues. Letting RCU-protected pointers "leak" out of an RCU read-side critical section is every bid as bad as letting them leak out -- 2.19.0.605.g01d371f741-goog