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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH, 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 174E3C07E85 for ; Fri, 7 Dec 2018 13:45:59 +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 DE18220868 for ; Fri, 7 Dec 2018 13:45:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="h/7EOvKH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DE18220868 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=OR0LomQ5NOmCFdIsL6QuSqa73CUPjuGe94B26iTKi10=; b=h/7EOvKHjv0IL/ 9TRov64DgcsHYHaqFpmtJr11TmuXOfVxdsWiahA7/zvYZb/zTgwO6UOwNxMgd+1iKeDZVhw0Bmk+O WjqUsqyNYfOkaRs17EQTsCYDsBSiRZVhAArjziu/ObuuvwOfeE46UH4cqYEfzi8oJRJnuMOPgwuiO +Vl8rurs9SoSi0yGZ8kmPwQAG0IIULdDl9UbJGpmojoMvY9VCCg5WDdVbTj102AV8LckzqJAoXJzS d2GBs8+uf16SAlxoARTgw4Y4mktNEIsWvNdg9Ew/hjl+Jz9BuRCp9WZn6IkDa1DtNyZMPa5GVZEtT I5ggbTe8q/wCUCt7JGEQ==; 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 1gVGRy-0002Hm-Ji; Fri, 07 Dec 2018 13:45:50 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVGRu-0002Dq-FN; Fri, 07 Dec 2018 13:45:47 +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 33EAF15AB; Fri, 7 Dec 2018 05:45:34 -0800 (PST) Received: from e105550-lin.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 A608C3F5AF; Fri, 7 Dec 2018 05:45:30 -0800 (PST) Date: Fri, 7 Dec 2018 13:45:21 +0000 From: Morten Rasmussen To: Atish Patra Subject: Re: [RFT PATCH v1 0/4] Unify CPU topology across ARM64 & RISC-V Message-ID: <20181207134509.GA5913@e105550-lin.cambridge.arm.com> References: <1543534100-3654-1-git-send-email-atish.patra@wdc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1543534100-3654-1-git-send-email-atish.patra@wdc.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181207_054546_520767_6BDAF63A X-CRM114-Status: GOOD ( 16.84 ) 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: Mark Rutland , devicetree@vger.kernel.org, Albert Ou , Thomas Gleixner , Juri Lelli , Ard Biesheuvel , Dmitriy Cherkasov , Anup Patel , Palmer Dabbelt , Will Deacon , linux-kernel@vger.kernel.org, Jeremy Linton , Sudeep Holla , "Peter Zijlstra \(Intel\)" , Rob Herring , Greg Kroah-Hartman , Catalin Marinas , "Rafael J. Wysocki" , linux-riscv@lists.infradead.org, Ingo Molnar , "moderated list:ARM64 PORT \(AARCH64 ARCHITECTURE\)" 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 Hi, On Thu, Nov 29, 2018 at 03:28:16PM -0800, Atish Patra wrote: > The cpu-map DT entry in ARM64 can describe the CPU topology in > much better way compared to other existing approaches. RISC-V can > easily adopt this binding to represent it's own CPU topology. > Thus, both cpu-map DT binding and topology parsing code can be > moved to a common location so that RISC-V or any other > architecture can leverage that. > > The relevant discussion regarding unifying cpu topology can be > found in [1]. > > arch_topology seems to be a perfect place to move the common > code. I have not introduced any functional changes in the moved > code. The only downside in this approach is that the capacity > code will be executed for RISC-V as well. But, it will exit > immediately after not able to find the appropriate DT node. If > the overhead is considered too much, we can always compile out > capacity related functions under a different config for the > architectures that do not support them. > > The patches have been tested for RISC-V and compile tested for > ARM64 & x86. The cpu-map bindings are used for arch/arm too, and so is arch_topology.c. In fact, it was introduced to allow code-sharing between arm and arm64. Applying patch three breaks arm. Moving the DT parsing to arch_topology.c we have to unify all three architectures. Be aware that arm and arm64 have some differences in how they detect cpu capacities. I think we might have to look at the split of code between arch/* and arch_topology.c again :-/ Morten _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel