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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,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 B3A53C282CE for ; Tue, 4 Jun 2019 17:30:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 852F7208E3 for ; Tue, 4 Jun 2019 17:30:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726572AbfFDRaC (ORCPT ); Tue, 4 Jun 2019 13:30:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48494 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726162AbfFDRaC (ORCPT ); Tue, 4 Jun 2019 13:30:02 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1EC3B2F8BC1; Tue, 4 Jun 2019 17:30:02 +0000 (UTC) Received: from llong.remote.csb (dhcp-17-85.bos.redhat.com [10.18.17.85]) by smtp.corp.redhat.com (Postfix) with ESMTP id E461919C69; Tue, 4 Jun 2019 17:30:00 +0000 (UTC) Subject: Re: [PATCH v8 15/19] locking/rwsem: Adaptive disabling of reader optimistic spinning To: Peter Zijlstra Cc: Ingo Molnar , Will Deacon , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" , linux-kernel@vger.kernel.org, x86@kernel.org, Davidlohr Bueso , Linus Torvalds , Tim Chen , huang ying References: <20190520205918.22251-1-longman@redhat.com> <20190520205918.22251-16-longman@redhat.com> <20190604092008.GJ3402@hirez.programming.kicks-ass.net> From: Waiman Long Organization: Red Hat Message-ID: <8e7d19ea-f2e6-f441-6ab9-cbff6d96589c@redhat.com> Date: Tue, 4 Jun 2019 13:30:00 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190604092008.GJ3402@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Tue, 04 Jun 2019 17:30:02 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/4/19 5:20 AM, Peter Zijlstra wrote: > On Mon, May 20, 2019 at 04:59:14PM -0400, Waiman Long wrote: >> @@ -286,6 +325,7 @@ struct rwsem_waiter { >> struct task_struct *task; >> enum rwsem_waiter_type type; >> unsigned long timeout; >> + long last_rowner; >> }; >> #define rwsem_first_waiter(sem) \ >> list_first_entry(&sem->wait_list, struct rwsem_waiter, list) >> +static inline bool rwsem_reader_phase_trylock(struct rw_semaphore *sem, >> + long last_rowner) >> +static inline bool rwsem_reader_phase_trylock(struct rw_semaphore *sem, >> + unsigned long last_rowner) >> + waiter.last_rowner = atomic_long_read(&sem->owner); > That's somewhat inconsistent wrt the type. I'll make it unsigned long, > as that is what makes most sense, given there's a pointer inside. Thank for spotting that, I will fix it. -Longman