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=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 76CFDC432C1 for ; Tue, 24 Sep 2019 11:08:22 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 F2AA52146E for ; Tue, 24 Sep 2019 11:08:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2AA52146E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46cz2C6kL6zDqD4 for ; Tue, 24 Sep 2019 21:08:19 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=softfail (mailfrom) smtp.mailfrom=kernel.org (client-ip=195.135.220.15; helo=mx1.suse.de; envelope-from=mhocko@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=fail (p=none dis=none) header.from=kernel.org Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46cymc4dCFzDqSR for ; Tue, 24 Sep 2019 20:56:31 +1000 (AEST) 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 2266CACEC; Tue, 24 Sep 2019 10:56:27 +0000 (UTC) Date: Tue, 24 Sep 2019 12:56:22 +0200 From: Michal Hocko To: Peter Zijlstra Subject: Re: [PATCH v6] numa: make node_to_cpumask_map() NUMA_NO_NODE aware Message-ID: <20190924105622.GH23050@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> <20190924074751.GB23050@dhcp22.suse.cz> <20190924091714.GJ2369@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190924091714.GJ2369@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dalias@libc.org, linux-sh@vger.kernel.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, heiko.carstens@de.ibm.com, jiaxun.yang@flygoat.com, linux-mips@vger.kernel.org, mwb@linux.vnet.ibm.com, paulus@samba.org, hpa@zytor.com, sparclinux@vger.kernel.org, chenhc@lemote.com, will@kernel.org, cai@lca.pw, linux-s390@vger.kernel.org, ysato@users.sourceforge.jp, x86@kernel.org, Yunsheng Lin , rppt@linux.ibm.com, borntraeger@de.ibm.com, dledford@redhat.com, mingo@redhat.com, jeffrey.t.kirsher@intel.com, jhogan@kernel.org, mattst88@gmail.com, len.brown@intel.com, gor@linux.ibm.com, anshuman.khandual@arm.com, gregkh@linuxfoundation.org, bp@alien8.de, luto@kernel.org, tglx@linutronix.de, naveen.n.rao@linux.vnet.ibm.com, linux-arm-kernel@lists.infradead.org, rth@twiddle.net, axboe@kernel.dk, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, ralf@linux-mips.org, tbogendoerfer@suse.de, paul.burton@mips.com, linux-alpha@vger.kernel.org, rafael@kernel.org, ink@jurassic.park.msu.ru, akpm@linux-foundation.org, robin.murphy@arm.com, davem@davemloft.net Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Archived-At: List-Archive: On Tue 24-09-19 11:17:14, Peter Zijlstra wrote: > On Tue, Sep 24, 2019 at 09:47:51AM +0200, Michal Hocko wrote: > > 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. > > Right, because the device node is wrong, so we fix _that_! > > > 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. > > The same thing I proposed earlier; force the device node to 0 (or any > other convenient random valid value) and issue a FW_BUG message to the > console. Why would you "fix" anything and how do you know that node 0 is the right choice? I have seen setups with node 0 without any memory and similar unexpected things. To be honest I really fail to see why to object to a simple semantic that NUMA_NO_NODE imply all usable cpus. Could you explain that please? -- Michal Hocko SUSE Labs