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 7B9EAC43381 for ; Fri, 15 Feb 2019 18:41:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 50E8C206C0 for ; Fri, 15 Feb 2019 18:41:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731674AbfBOSlF (ORCPT ); Fri, 15 Feb 2019 13:41:05 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:37532 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727890AbfBOSlE (ORCPT ); Fri, 15 Feb 2019 13:41:04 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8F399A78; Fri, 15 Feb 2019 10:41:03 -0800 (PST) Received: from fuggles.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 937D53F589; Fri, 15 Feb 2019 10:40:58 -0800 (PST) Date: Fri, 15 Feb 2019 18:40:56 +0000 From: Will Deacon To: Peter Zijlstra Cc: Waiman Long , Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-c6x-dev@linux-c6x.org, uclinux-h8-devel@lists.sourceforge.jp, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, nios2-dev@lists.rocketboards.org, openrisc@lists.librecores.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org, x86@kernel.org, Arnd Bergmann , Borislav Petkov , "H. Peter Anvin" , Davidlohr Bueso , Linus Torvalds , Andrew Morton , Tim Chen Subject: Re: [PATCH v4 0/3] locking/rwsem: Rwsem rearchitecture part 0 Message-ID: <20190215184056.GC15084@fuggles.cambridge.arm.com> References: <1550095217-12047-1-git-send-email-longman@redhat.com> <20190214103715.GI32494@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190214103715.GI32494@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.11.1+86 (6f28e57d73f2) () Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 14, 2019 at 11:37:15AM +0100, Peter Zijlstra wrote: > On Wed, Feb 13, 2019 at 05:00:14PM -0500, Waiman Long wrote: > > v4: > > - Remove rwsem-spinlock.c and make all archs use rwsem-xadd.c. > > > > v3: > > - Optimize __down_read_trylock() for the uncontended case as suggested > > by Linus. > > > > v2: > > - Add patch 2 to optimize __down_read_trylock() as suggested by PeterZ. > > - Update performance test data in patch 1. > > > > The goal of this patchset is to remove the architecture specific files > > for rwsem-xadd to make it easer to add enhancements in the later rwsem > > patches. It also removes the legacy rwsem-spinlock.c file and make all > > the architectures use one single implementation of rwsem - rwsem-xadd.c. > > > > Waiman Long (3): > > locking/rwsem: Remove arch specific rwsem files > > locking/rwsem: Remove rwsem-spinlock.c & use rwsem-xadd.c for all > > archs > > locking/rwsem: Optimize down_read_trylock() > > Acked-by: Peter Zijlstra (Intel) > > with the caveat that I'm happy to exchange patch 3 back to my earlier > suggestion in case Will expesses concerns wrt the ARM64 performance of > Linus' suggestion. Right, the current proposal doesn't work well for us, unfortunately. Which was your earlier suggestion? Will