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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 93D48C43381 for ; Tue, 26 Feb 2019 18:20:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6480A20C01 for ; Tue, 26 Feb 2019 18:20:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729159AbfBZSUX (ORCPT ); Tue, 26 Feb 2019 13:20:23 -0500 Received: from mx2.suse.de ([195.135.220.15]:50242 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728793AbfBZSUW (ORCPT ); Tue, 26 Feb 2019 13:20:22 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 827E8ACD3; Tue, 26 Feb 2019 18:20:21 +0000 (UTC) Date: Tue, 26 Feb 2019 10:20:13 -0800 From: Davidlohr Bueso To: Waiman Long Cc: Peter Zijlstra , Ingo Molnar , Will Deacon , Thomas Gleixner , linux-kernel@vger.kernel.org, x86@kernel.org, Arnd Bergmann , Borislav Petkov , "H. Peter Anvin" , Linus Torvalds , Andrew Morton , Tim Chen Subject: Re: [PATCH-tip v2 00/10] locking/rwsem: Rwsem rearchitecture part 1 Message-ID: <20190226182013.iynflounqufjtnli@linux-r8p5> References: <1550263810-31947-1-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <1550263810-31947-1-git-send-email-longman@redhat.com> User-Agent: NeoMutt/20180323 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 15 Feb 2019, Waiman Long wrote: > v2: > - Sync up to v4 of the part 0 patch. > - Remove the rwsem.h->rwsem-xadd.h renaming patch & change patches > to modify rwsem.h instead of rwsem-xadd.h. > - Add a new patch to micro-optimize rwsem_try_read_lock_unqueued(). > >This is part 1 of a 3-part (0/1/2) series to rearchitect the internal >operation of rwsem. This depends on the v4 part 0 patches sent out >previously > >https://lore.kernel.org/lkml/1550095217-12047-1-git-send-email-longman@redhat.com > >This part lays the foundation for part 2 without making any functional >changes. This part includes the following changes: > > 1) Move code around and micro-optimize rwsem_try_read_lock_unqueued() > (patches 1-4). > 2) Enhance the DEBUG_RWSEMS_WARN_ON() macro to provide more information > and add additional checks (patches 5 & 6). > 3) Make the core qspinlock_stat.h code generic (lock event counting) > so that it can be used by all the architectures as well as other > locking subsystems such as rwsem (patches 7-10). Lock event > counting help us visualize how frequently a code path is being > used as well as spotting abnormal behavior due to bugs in the code > without noticeably affecting kernel performance and hence behavior. > >Both (2) and (3) are useful debugging aids. Yes, this will come in handy in the future. Feel free to add my: Acked-by: Davidlohr Bueso Thanks.