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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34996C38142 for ; Tue, 17 Jan 2023 23:13:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229902AbjAQXND (ORCPT ); Tue, 17 Jan 2023 18:13:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229566AbjAQXLZ (ORCPT ); Tue, 17 Jan 2023 18:11:25 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF457683F8 for ; Tue, 17 Jan 2023 12:53:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673988809; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kK9jjV9LP02qyv4y6+sL2kQpufhJ4FqsFgh0MZZolJ4=; b=c5lMSLWVkMbtouTkpAileyhU2gC59N2OMdVgltfXYfjtmDSkAayTZ44UMLMeiT7u1tlYGY UqpT5GvCkJiWmPx+D6m+EEaS8QiDkN8Wgk6KcVDPXex2RjfOfx8I1Sxn4J4IIVGUApxKgm wlL/xjvyY9Rq96HT3AvZRqmcb9OmuOg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-390-XDlHVebtNmCyO3FtIvn-Ag-1; Tue, 17 Jan 2023 15:53:23 -0500 X-MC-Unique: XDlHVebtNmCyO3FtIvn-Ag-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D5B7A811E9C; Tue, 17 Jan 2023 20:53:22 +0000 (UTC) Received: from [10.18.17.153] (dhcp-17-153.bos.redhat.com [10.18.17.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id 58FBF7AE5; Tue, 17 Jan 2023 20:53:22 +0000 (UTC) Message-ID: Date: Tue, 17 Jan 2023 15:53:22 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.0 Subject: Re: [PATCH v6 0/6] lockinig/rwsem: Fix rwsem bugs & enable true lock handoff Content-Language: en-US To: Peter Zijlstra , Ingo Molnar , Will Deacon , Boqun Feng Cc: linux-kernel@vger.kernel.org, john.p.donnelly@oracle.com, Hillf Danton , Mukesh Ojha , =?UTF-8?B?VGluZzExIFdhbmcg546L5am3?= References: <20221118022016.462070-1-longman@redhat.com> From: Waiman Long In-Reply-To: <20221118022016.462070-1-longman@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/17/22 21:20, Waiman Long wrote: > v6: > - Fix an error in patch 2 reported by kernel test robot. > > v5: > - Drop patch 2 and replace it with 2 new patches disabling preemption on > all reader functions and writer functions respectively. The other > patches are adjusted accordingly. > > v4: > - Update patch descriptions in patches 1 & 2 to make clear the live > lock conditions that are being fixed by these patches. There is no code > change from v3. > > It turns out the current waiter optimistic spinning code does not work > that well if we have RT tasks in the mix. This patch series include two > different fixes to resolve those issues. The last 3 patches modify the > handoff code to implement true lock handoff similar to that of mutex. > > Waiman Long (6): > locking/rwsem: Prevent non-first waiter from spinning in down_write() > slowpath > locking/rwsem: Disable preemption at all down_read*() and up_read() > code paths > locking/rwsem: Disable preemption at all down_write*() and up_write() > code paths > locking/rwsem: Change waiter->hanodff_set to a handoff_state enum > locking/rwsem: Enable direct rwsem lock handoff > locking/rwsem: Update handoff lock events tracking > > kernel/locking/lock_events_list.h | 6 +- > kernel/locking/rwsem.c | 240 ++++++++++++++++++++++-------- > 2 files changed, 182 insertions(+), 64 deletions(-) > Peter, I know that you are busy these days. Do have any further comment or suggestion on this patch series? Looking forward to your reply. Thanks, Longman