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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 64F68C43381 for ; Wed, 20 Feb 2019 14:48:10 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 35AB321902 for ; Wed, 20 Feb 2019 14:48:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OGLCe3q4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 35AB321902 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=2nKqDARUPAwqZkPDzI7rOLM07aKbtcmI2QLM2F32bls=; b=OGLCe3q4oPXFgF 2h0WxM4LRYtYZP6WXeR1xM5XJWRHTtdYatw/vzH/callQwe/Ha9i1YF3JS1ZYqvcTCPjUyc+aY34C O7OWjTSpt8HC3EtzEHa62WmsPevPNFGYYBJ5wCGls5yvz15O+1hQLfNHPnVEI2F3CvDd8ZdWFKz2t NuEOQiZBu+SilFD69MAx0uTZou3eGFA2ssZvITQHndlj/3Scl28pJSYWd3GJypKns/0A6vHzoVpaT 63LZE8iGolOeCdYey7TDKndKMYsV+8S5JuM+lwMV26nQk8FJDBt2/VAl6GrlMABMb07YLgSH8FAT/ G8BpBeCAkonCjsn7jpiw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gwTAN-0000J9-IZ; Wed, 20 Feb 2019 14:48:07 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gwTAK-0000If-U4; Wed, 20 Feb 2019 14:48:06 +0000 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 2C2FA15AB; Wed, 20 Feb 2019 06:48:04 -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 312643F5C1; Wed, 20 Feb 2019 06:47:59 -0800 (PST) Date: Wed, 20 Feb 2019 14:47:56 +0000 From: Will Deacon To: Waiman Long Subject: Re: [PATCH v4 2/3] locking/rwsem: Remove rwsem-spinlock.c & use rwsem-xadd.c for all archs Message-ID: <20190220144756.GK7523@fuggles.cambridge.arm.com> References: <1550095217-12047-1-git-send-email-longman@redhat.com> <1550095217-12047-3-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1550095217-12047-3-git-send-email-longman@redhat.com> User-Agent: Mutt/1.11.1+86 (6f28e57d73f2) () X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190220_064804_979685_4AFBDB83 X-CRM114-Status: GOOD ( 17.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , linux-mips@vger.kernel.org, "H. Peter Anvin" , sparclinux@vger.kernel.org, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Davidlohr Bueso , linux-c6x-dev@linux-c6x.org, linux-hexagon@vger.kernel.org, x86@kernel.org, Ingo Molnar , uclinux-h8-devel@lists.sourceforge.jp, linux-xtensa@linux-xtensa.org, Arnd Bergmann , linux-um@lists.infradead.org, linux-m68k@lists.linux-m68k.org, openrisc@lists.librecores.org, Borislav Petkov , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Tim Chen , linux-parisc@vger.kernel.org, Linus Torvalds , linux-kernel@vger.kernel.org, linux-alpha@vger.kernel.org, nios2-dev@lists.rocketboards.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Feb 13, 2019 at 05:00:16PM -0500, Waiman Long wrote: > Currently, we have two different implementation of rwsem: > 1) CONFIG_RWSEM_GENERIC_SPINLOCK (rwsem-spinlock.c) > 2) CONFIG_RWSEM_XCHGADD_ALGORITHM (rwsem-xadd.c) > > As we are going to use a single generic implementation for rwsem-xadd.c > and no architecture-specific code will be needed, there is no point > in keeping two different implementations of rwsem. In most cases, the > performance of rwsem-spinlock.c will be worse. It also doesn't get all > the performance tuning and optimizations that had been implemented in > rwsem-xadd.c over the years. > > For simplication, we are going to remove rwsem-spinlock.c and make all > architectures use a single implementation of rwsem - rwsem-xadd.c. > > All references to RWSEM_GENERIC_SPINLOCK and RWSEM_XCHGADD_ALGORITHM > in the code are removed. > > Suggested-by: Peter Zijlstra > Signed-off-by: Waiman Long > --- > arch/alpha/Kconfig | 7 - > arch/arc/Kconfig | 3 - > arch/arm/Kconfig | 4 - > arch/arm64/Kconfig | 3 - > arch/c6x/Kconfig | 3 - > arch/csky/Kconfig | 3 - > arch/h8300/Kconfig | 3 - > arch/hexagon/Kconfig | 6 - > arch/ia64/Kconfig | 4 - > arch/m68k/Kconfig | 7 - > arch/microblaze/Kconfig | 6 - > arch/mips/Kconfig | 7 - > arch/nds32/Kconfig | 3 - > arch/nios2/Kconfig | 3 - > arch/openrisc/Kconfig | 6 - > arch/parisc/Kconfig | 6 - > arch/powerpc/Kconfig | 7 - > arch/riscv/Kconfig | 3 - > arch/s390/Kconfig | 6 - > arch/sh/Kconfig | 6 - > arch/sparc/Kconfig | 8 - > arch/unicore32/Kconfig | 6 - > arch/x86/Kconfig | 3 - > arch/x86/um/Kconfig | 6 - > arch/xtensa/Kconfig | 3 - > include/linux/rwsem-spinlock.h | 47 ------ > include/linux/rwsem.h | 5 - > kernel/Kconfig.locks | 2 +- > kernel/locking/Makefile | 4 +- > kernel/locking/rwsem-spinlock.c | 339 ---------------------------------------- > kernel/locking/rwsem.h | 3 - > 31 files changed, 2 insertions(+), 520 deletions(-) > delete mode 100644 include/linux/rwsem-spinlock.h > delete mode 100644 kernel/locking/rwsem-spinlock.c Another nice cleanup, and it looks like the optimistic spinning in the xadd implementation is predicated on ARCH_SUPPORTS_ATOMIC_RMW, so we're all good there too. Acked-by: Will Deacon Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel