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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 64D77C433E0 for ; Tue, 16 Jun 2020 20:24:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A250207DD for ; Tue, 16 Jun 2020 20:24:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="PnbzCTXb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731425AbgFPUYq (ORCPT ); Tue, 16 Jun 2020 16:24:46 -0400 Received: from mail.efficios.com ([167.114.26.124]:45600 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726428AbgFPUYp (ORCPT ); Tue, 16 Jun 2020 16:24:45 -0400 Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id C2E342BC34E; Tue, 16 Jun 2020 16:24:44 -0400 (EDT) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id g_0CiEaMw_Mx; Tue, 16 Jun 2020 16:24:44 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 89AD12BC642; Tue, 16 Jun 2020 16:24:44 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 89AD12BC642 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1592339084; bh=18w6fF8mOh+rBs9AqW0wGKeQUee1C4pGw/+J41u2jA0=; h=Date:From:To:Message-ID:MIME-Version; b=PnbzCTXbyQxVMx6M8PLd4B54MnUMJRTyOPUtgOPM9SRzcStPX5Yrbfbtmj/Th5kOg JauYyCF/Lc92OkGpuFTC6x+Kkok1XXG4jmS0SzQXdmeFoVn7mZ9ivOdIjn7Dc/cJcR ls5WIgjZfWoilMfzjoK4KrxdfqbQyL7ZQsfwsryX/ur9J9RM8haIHUKEKoye7bd7gI 1mhOQ52XGk+3CuRp7wBQy0ff0LWjbuFpHezDHPPXB0JuAHdswctRu+6rIHp6T5z7ur FT09T1hkHEDMaiiEpZtFKLJqxuJY6wd5YRAO1QOJRxopxqdJZkCLwz3EPeC67ZX+f7 faTnV0lqvQluA== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id U7VcYXgjh0JG; Tue, 16 Jun 2020 16:24:44 -0400 (EDT) Received: from mail03.efficios.com (mail03.efficios.com [167.114.26.124]) by mail.efficios.com (Postfix) with ESMTP id 799C22BC72C; Tue, 16 Jun 2020 16:24:44 -0400 (EDT) Date: Tue, 16 Jun 2020 16:24:44 -0400 (EDT) From: Mathieu Desnoyers To: Chaitanya Kulkarni Cc: paulmck , Josh Triplett , rcu , rostedt , Lai Jiangshan Message-ID: <1909772924.4639.1592339084357.JavaMail.zimbra@efficios.com> In-Reply-To: References: Subject: Re: Question about list_sort() RCU version. MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.26.124] X-Mailer: Zimbra 8.8.15_GA_3945 (ZimbraWebClient - FF77 (Linux)/8.8.15_GA_3928) Thread-Topic: Question about list_sort() RCU version. Thread-Index: AQHWRBs42t9q8JLtOk6vT+rVgdWIUtSFnJSl Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org ----- On Jun 16, 2020, at 4:17 PM, Chaitanya Kulkarni Chaitanya.Kulkarni@wdc.com wrote: > Hi RCU maintainers and experts, > > I'm working on a linux kernel upstream project which is in the tree. > With the POC I can already see that significant performance improvement > with RCU in the fast path which are replacing rw semaphore, but not > having list_sort() rcu variant is blocking the developement and getting > code upstream. Why do you need list_sort() ? Is there any way you could simply insert your new elements into the list in already-sorted order ? This would ensure that the list is always in a sorted state, which I suspect will be expected by RCU readers. Thanks, Mathieu > > I was not able to find the such helper implemented for the RCU flavor of > list. > > Can someone provide information about :- > > 1. Is there any plan to have list_sort_rcu() ? if so when can we expect > that ? (Also how can I help ?) > > 2. In case there is no plan what are design considerations if someone > wants to implement the code and submit it upstream ? > (Also how can I help here ? -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com