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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 BB875C28CF6 for ; Wed, 1 Aug 2018 08:53:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DDAC208A2 for ; Wed, 1 Aug 2018 08:53:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6DDAC208A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lge.com 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 S2388749AbeHAKhk (ORCPT ); Wed, 1 Aug 2018 06:37:40 -0400 Received: from lgeamrelo11.lge.com ([156.147.23.51]:60989 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387502AbeHAKhk (ORCPT ); Wed, 1 Aug 2018 06:37:40 -0400 Received: from unknown (HELO lgeamrelo02.lge.com) (156.147.1.126) by 156.147.23.51 with ESMTP; 1 Aug 2018 17:52:57 +0900 X-Original-SENDERIP: 156.147.1.126 X-Original-MAILFROM: byungchul.park@lge.com Received: from unknown (HELO X58A-UD3R) (10.177.222.33) by 156.147.1.126 with ESMTP; 1 Aug 2018 17:52:56 +0900 X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com Date: Wed, 1 Aug 2018 17:52:48 +0900 From: Byungchul Park To: "Huang, Ying" Cc: "Paul E. McKenney" , linux-kernel@vger.kernel.org, kernel-team@lge.com, peterz@infradead.org, mingo@kernel.org, jiangshanlai@gmail.com, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, joel@joelfernandes.org, len.brown@intel.com, glider@google.com, peter@hurleysoftware.com, aik@ozlabs.ru Subject: Re: [QUESTION] llist: Comment releasing 'must delete' restriction before traversing Message-ID: <20180801085248.GA21343@X58A-UD3R> References: <1532998716-5037-1-git-send-email-byungchul.park@lge.com> <20180731043042.GJ24813@linux.vnet.ibm.com> <20180731092950.GB12241@X58A-UD3R> <878t5qabgx.fsf@yhuang-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <878t5qabgx.fsf@yhuang-dev.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 01, 2018 at 01:43:10PM +0800, Huang, Ying wrote: > Byungchul Park writes: > > > I think rcu list also works well. But I decided to use llist because > > llist is simpler and has one less pointer. > > > > Just to be sure, let me explain my use case more: > > > > 1. Introduced a global list where single linked list is sufficient. > > 2. All operations I need is to add items and traverse the list. > > 3. Ensure the operations always happen within irq-disabled section. > > 4. I'm considering CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG properly. > > 5. The list can be accessed by every CPU concurrently. > > > > Can you provide more information about where is your use case? Is it a > kernel driver? Then it is better to submit the patch together with its > user. > > And I have the similar concern as Steven Rostedt. That is, if you are > the only user forever, it's not necessary to change the common code. I'm sorry the patch is too complicated and premature to share at the moment so I don't know how to extract only what you're asking me for. Thanks anyway. The common code doesn't have to be changed then. > Best Regards, > Huang, Ying