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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 61EDDC33CAD for ; Mon, 13 Jan 2020 13:22:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C29D214AF for ; Mon, 13 Jan 2020 13:22:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728842AbgAMNWW (ORCPT ); Mon, 13 Jan 2020 08:22:22 -0500 Received: from foss.arm.com ([217.140.110.172]:39426 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728646AbgAMNWS (ORCPT ); Mon, 13 Jan 2020 08:22:18 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 979E713D5; Mon, 13 Jan 2020 05:22:17 -0800 (PST) Received: from e105550-lin.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 96D1E3F68E; Mon, 13 Jan 2020 05:22:16 -0800 (PST) Date: Mon, 13 Jan 2020 13:22:14 +0000 From: Morten Rasmussen To: Valentin Schneider Cc: "Zengtao (B)" , Sudeep Holla , Linuxarm , Greg Kroah-Hartman , "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] cpu-topology: warn if NUMA configurations conflicts with lower layer Message-ID: <20200113132214.GD10914@e105550-lin.cambridge.arm.com> References: <1577088979-8545-1-git-send-email-prime.zeng@hisilicon.com> <20191231164051.GA4864@bogus> <678F3D1BB717D949B966B68EAEB446ED340AE1D3@dggemm526-mbx.china.huawei.com> <20200102112955.GC4864@bogus> <678F3D1BB717D949B966B68EAEB446ED340AEB67@dggemm526-mbx.china.huawei.com> <20200109105228.GB10914@e105550-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 12, 2020 at 01:22:02PM +0000, Valentin Schneider wrote: > On 09/01/2020 10:52, Morten Rasmussen wrote: > >> AFAIA what matters here is memory controllers, less so LLCs. Cores within > >> a single die could have private LLCs and separate memory controllers, or > >> shared LLC and separate memory controllers. > > > > Don't confuse cache boundaries, packages and nodes :-) > > > > core_siblings are cpus in the same package and doesn't say anything > > about cache boundaries. It is not given that there is sched_domain that > > matches the core_sibling span. > > > > The MC sched_domain is supposed to match the LLC span which might > > different for core_siblings. So the about example should be valid for a > > NUMA-in-package system with one package containing two nodes. > > > > Right, the point I was trying to make is that node boundaries can be pretty > much anything, so nodes can span over LLCs, or LLCs can span over nodes, > which is why we need checks such as the one in arch_topology() that lets us > build up a usable domain hierarchy (which cares about LLCs, at least at some > level). Indeed. The topology masks can't always be used as is to define the sched_domain hierarchy.