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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 9FDF7C432C1 for ; Tue, 24 Sep 2019 07:48:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6C72820673 for ; Tue, 24 Sep 2019 07:48:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569311282; bh=Q0dx1bFxaf2xHgxN4/UXveMRnOufT7B40M+lU3oaCI0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=d2k0VhwfTzDpqUfhrTXX9zFeNLGCxer1SCNfDKRTqDqlaeujvjD0eOYOfAxLgJPyX vCUCdhvN9gU7M1Lc8GpYWoHqSrH3z9Rh9bDkaTJ6IlDOcEFENiMmpgVZrMiLNcTzwL HP66jrFn4UQLDiNytDF28q3kXPNCXUSnUaAuB7oY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2438807AbfIXHsB (ORCPT ); Tue, 24 Sep 2019 03:48:01 -0400 Received: from mx2.suse.de ([195.135.220.15]:52168 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389597AbfIXHsA (ORCPT ); Tue, 24 Sep 2019 03:48:00 -0400 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 C8B0CAFA5; Tue, 24 Sep 2019 07:47:56 +0000 (UTC) Date: Tue, 24 Sep 2019 09:47:51 +0200 From: Michal Hocko To: Peter Zijlstra Cc: Yunsheng Lin , catalin.marinas@arm.com, will@kernel.org, mingo@redhat.com, bp@alien8.de, rth@twiddle.net, ink@jurassic.park.msu.ru, mattst88@gmail.com, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, heiko.carstens@de.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, ysato@users.sourceforge.jp, dalias@libc.org, davem@davemloft.net, ralf@linux-mips.org, paul.burton@mips.com, jhogan@kernel.org, jiaxun.yang@flygoat.com, chenhc@lemote.com, akpm@linux-foundation.org, rppt@linux.ibm.com, anshuman.khandual@arm.com, tglx@linutronix.de, cai@lca.pw, robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, hpa@zytor.com, x86@kernel.org, dave.hansen@linux.intel.com, luto@kernel.org, len.brown@intel.com, axboe@kernel.dk, dledford@redhat.com, jeffrey.t.kirsher@intel.com, linux-alpha@vger.kernel.org, naveen.n.rao@linux.vnet.ibm.com, mwb@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, tbogendoerfer@suse.de, linux-mips@vger.kernel.org, rafael@kernel.org, gregkh@linuxfoundation.org Subject: Re: [PATCH v6] numa: make node_to_cpumask_map() NUMA_NO_NODE aware Message-ID: <20190924074751.GB23050@dhcp22.suse.cz> References: <1568724534-146242-1-git-send-email-linyunsheng@huawei.com> <20190923151519.GE2369@hirez.programming.kicks-ass.net> <20190923152856.GB17206@dhcp22.suse.cz> <20190923154852.GG2369@hirez.programming.kicks-ass.net> <20190923165235.GD17206@dhcp22.suse.cz> <20190923203410.GI2369@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190923203410.GI2369@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 23-09-19 22:34:10, Peter Zijlstra wrote: > On Mon, Sep 23, 2019 at 06:52:35PM +0200, Michal Hocko wrote: [...] > > I even the > > ACPI standard is considering this optional. Yunsheng Lin has referred to > > the specific part of the standard in one of the earlier discussions. > > Trying to guess the node affinity is worse than providing all CPUs IMHO. > > I'm saying the ACPI standard is wrong. Even if you were right on this the reality is that a HW is likely to follow that standard and we cannot rule out NUMA_NO_NODE being specified. As of now we would access beyond the defined array and that is clearly a bug. Let's assume that this is really a bug for a moment. What are you going to do about that? BUG_ON? I do not really see any solution besides to either provide something sensible or BUG_ON. If you are worried about a conditional then this should be pretty easy to solve by starting the array at -1 index and associate it with the online cpu mask. -- Michal Hocko SUSE Labs