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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS 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 66827C43387 for ; Mon, 7 Jan 2019 15:35:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42B5D2173C for ; Mon, 7 Jan 2019 15:35:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730000AbfAGPfg (ORCPT ); Mon, 7 Jan 2019 10:35:36 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39244 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726873AbfAGPfg (ORCPT ); Mon, 7 Jan 2019 10:35:36 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A6C2D2D7F3; Mon, 7 Jan 2019 15:35:34 +0000 (UTC) Received: from llong.remote.csb (dhcp-17-223.bos.redhat.com [10.18.17.223]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9850D5D75F; Mon, 7 Jan 2019 15:35:31 +0000 (UTC) Subject: Re: [RFC] locking/rwsem: Avoid issuing wakeup before setting the reader waiter to nil To: Peter Zijlstra Cc: Yongji Xie , dave@stgolabs.net, mingo@redhat.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, Xie Yongji , zhangyu31@baidu.com, liuqi16@baidu.com, yuanlinsi01@baidu.com, nixun@baidu.com, lilin24@baidu.com, andrea.parri@amarulasolutions.com References: <20181129172700.GA11632@hirez.programming.kicks-ass.net> <20181129180828.GA11650@hirez.programming.kicks-ass.net> <729ceddb-dd9a-ec2a-f74e-03fa4d7e65e8@redhat.com> <20181129213017.v3eljor54lfpoug2@linux-r8p5> <20181129213421.wwvhsjql3m3lvtv4@linux-r8p5> <20181129221714.GF11632@hirez.programming.kicks-ass.net> <20181217113718.GB4900@worktop.programming.kicks-ass.net> <20190107153125.GL2218@hirez.programming.kicks-ass.net> From: Waiman Long Openpgp: preference=signencrypt Autocrypt: addr=longman@redhat.com; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190107153125.GL2218@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Mon, 07 Jan 2019 15:35:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/07/2019 10:31 AM, Peter Zijlstra wrote: > On Mon, Jan 07, 2019 at 09:35:09AM -0500, Waiman Long wrote: >> On 12/17/2018 08:12 AM, Yongji Xie wrote: >>> On Mon, 17 Dec 2018 at 19:37, Peter Zijlstra wrote: >>>> On Mon, Dec 10, 2018 at 11:12:52PM +0800, Yongji Xie wrote: >>>>> Hi Peter, >>>>> >>>>> Please let me know If there is any progress on this issue. Thank you! >>>> Right, sorry, my brain was filled with snot and didn't want to make >>>> sense of things. >>>> >>>> I've put some patches here: >>>> >>>> git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git locking/core >>>> >>>> Could you have a look? >>> That looks good to me. Thank you! >>> >>> Thanks, >>> Yongji >> Peter, >> >> Are you planning to move the patch over to tip as the merge window has >> just closed? > Sorry; yes, probably, I just got back from a 2 week holiday and am > somewhat scrambling to remember where I left off and what all landed in > my inbox. Happy New Year! I have bug reports on some mysterious rwsem related hangs which I think can probably be fixed by this patch. That is why I am looking forward for it to land into the tip tree. Thanks, Longman