From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=Itbs=W5=lists.ozlabs.org=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@kernel.org>
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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED,
	FSL_HELO_FAKE,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,
	URIBL_BLOCKED,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 5146DC3A59E
	for <linuxppc-dev@archiver.kernel.org>; Mon,  2 Sep 2019 18:25:06 +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 BDAA6208E4
	for <linuxppc-dev@archiver.kernel.org>; Mon,  2 Sep 2019 18:25:05 +0000 (UTC)
Authentication-Results: mail.kernel.org;
	dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="X1Hbz3B0"
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BDAA6208E4
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 46MdmH1HM0zDq9j
	for <linuxppc-dev@archiver.kernel.org>; Tue,  3 Sep 2019 04:25:03 +1000 (AEST)
Authentication-Results: lists.ozlabs.org;
 spf=pass (mailfrom) smtp.mailfrom=gmail.com
 (client-ip=2a00:1450:4864:20::442; helo=mail-wr1-x442.google.com;
 envelope-from=mingo.kernel.org@gmail.com; receiver=<UNKNOWN>)
Authentication-Results: lists.ozlabs.org;
 dmarc=fail (p=none dis=none) header.from=kernel.org
Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key;
 unprotected) header.d=gmail.com header.i=@gmail.com header.b="X1Hbz3B0"; 
 dkim-atps=neutral
Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com
 [IPv6:2a00:1450:4864:20::442])
 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
 key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256)
 (No client certificate requested)
 by lists.ozlabs.org (Postfix) with ESMTPS id 46Mdjw3TvTzDqCq
 for <linuxppc-dev@lists.ozlabs.org>; Tue,  3 Sep 2019 04:22:59 +1000 (AEST)
Received: by mail-wr1-x442.google.com with SMTP id g7so14918984wrx.2
 for <linuxppc-dev@lists.ozlabs.org>; Mon, 02 Sep 2019 11:22:59 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025;
 h=sender:date:from:to:cc:subject:message-id:references:mime-version
 :content-disposition:in-reply-to:user-agent;
 bh=8A/kzDKosPuqQJbNKUfUKEZ3g88LloK7fbrgo3dQ42Q=;
 b=X1Hbz3B066PMs/wFzGMdVngPlmfveUnUO/NuPBD+yyoHoS/9BlKzuv6Ckhzew5pOv/
 ULDRFPERFg0KWvkfbvIML575gChH/77GxlL9dyk0qa5UbCTonhi5xuz7mlZvij7GUpvU
 l8QZ4qFlwn7TuZaW7UAUDyhkPZsuaTeATTFAGn7Qd8HvQZmhQky+CvoiJmtue1FDyubn
 P/yL1vPboPGUH9tzCouFRzdLC3HVehGXkouMh5YjL0urGmjTKniylfgtdMV0yebN/eRz
 7uoeQ6KEpliOCJn3osbrEoocuMhC4Yp1FBqhiDOASFKIs2V0PKzjMQyq6vK0Cfy1LKoW
 ARkQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20161025;
 h=x-gm-message-state:sender:date:from:to:cc:subject:message-id
 :references:mime-version:content-disposition:in-reply-to:user-agent;
 bh=8A/kzDKosPuqQJbNKUfUKEZ3g88LloK7fbrgo3dQ42Q=;
 b=VOPNGWgXsSHg7JGEfQiJ7xh4jt63WyXcdb9C9nPgf1nqES2uaiN+ktl9dUbcc1lOi0
 i8o8Pp2Ra5V+9A0cszDG0O1Ii2dLVnLn6y30BjNo7aVnp12ai8GJcYhcNn5lMVrnLfgk
 n9svXEgFgqTi0qJRTHIo20MOgHjASAQqAFSoCeVPhGGDorWOa6YA09eM1xhvDYFrryJO
 xcFyxFPrU3+cTNVZr++ze3oR5NrTlSYD0xdPdAo+MsMVDRfulv5RxFCnuZAc/BRZs1ob
 Cn7I1GKZirap6+VXXARwv/cEOYgNJDWTq5gmZT/rHEVd0yT/RF5ZXQdmYQ2Y80bu7rkQ
 lhaQ==
X-Gm-Message-State: APjAAAVBdlp5sxhCJZ+AtuP4nAOLr5mmeY2u+R5OZB7pPJhM1VSaNWAX
 q9NGuzLsfeCraP/YmbdSW84=
X-Google-Smtp-Source: APXvYqzIotofKxre9TSXVZbGJRzt2MUIul0zkl0rNXE9gzwa4Z1Lg36GB0S2Qsdlyw89JY76H73b4Q==
X-Received: by 2002:adf:a4c8:: with SMTP id h8mr15266864wrb.293.1567448576040; 
 Mon, 02 Sep 2019 11:22:56 -0700 (PDT)
Received: from gmail.com (2E8B0CD5.catv.pool.telekom.hu. [46.139.12.213])
 by smtp.gmail.com with ESMTPSA id z21sm3901958wmf.30.2019.09.02.11.22.53
 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);
 Mon, 02 Sep 2019 11:22:55 -0700 (PDT)
Date: Mon, 2 Sep 2019 20:22:52 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v2 2/9] x86: numa: check the node id consistently for x86
Message-ID: <20190902182252.GC35858@gmail.com>
References: <1567231103-13237-1-git-send-email-linyunsheng@huawei.com>
 <1567231103-13237-3-git-send-email-linyunsheng@huawei.com>
 <20190831085539.GG2369@hirez.programming.kicks-ass.net>
 <4d89c688-49e4-a2aa-32ee-65e36edcd913@huawei.com>
 <20190831161247.GM2369@hirez.programming.kicks-ass.net>
 <ae64285f-5134-4147-7b02-34bb5d519e8c@huawei.com>
 <20190902072542.GN2369@hirez.programming.kicks-ass.net>
 <5fa2aa99-89fa-cd41-b090-36a23cfdeb73@huawei.com>
 <20190902125644.GQ2369@hirez.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190902125644.GQ2369@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 <linuxppc-dev.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linuxppc-dev/>
List-Post: <mailto:linuxppc-dev@lists.ozlabs.org>
List-Help: <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linuxppc-dev>,
 <mailto:linuxppc-dev-request@lists.ozlabs.org?subject=subscribe>
Cc: dalias@libc.org, linux-sh@vger.kernel.org, catalin.marinas@arm.com,
 dave.hansen@linux.intel.com, heiko.carstens@de.ibm.com, linuxarm@huawei.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, bp@alien8.de, linux-s390@vger.kernel.org,
 ysato@users.sourceforge.jp, x86@kernel.org, paul.burton@mips.com,
 rppt@linux.ibm.com, borntraeger@de.ibm.com, dledford@redhat.com,
 mingo@redhat.com, jeffrey.t.kirsher@intel.com, jhogan@kernel.org,
 nfont@linux.vnet.ibm.com, mattst88@gmail.com, len.brown@intel.com,
 gor@linux.ibm.com, anshuman.khandual@arm.com,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>, ink@jurassic.park.msu.ru,
 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, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
 linux-kernel@vger.kernel.org, ralf@linux-mips.org, tbogendoerfer@suse.de,
 Yunsheng Lin <linyunsheng@huawei.com>, linux-alpha@vger.kernel.org, cai@lca.pw,
 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"
 <linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org>


* Peter Zijlstra <peterz@infradead.org> wrote:

> On Mon, Sep 02, 2019 at 08:25:24PM +0800, Yunsheng Lin wrote:
> > On 2019/9/2 15:25, Peter Zijlstra wrote:
> > > On Mon, Sep 02, 2019 at 01:46:51PM +0800, Yunsheng Lin wrote:
> > >> On 2019/9/1 0:12, Peter Zijlstra wrote:
> > > 
> > >>> 1) because even it is not set, the device really does belong to a node.
> > >>> It is impossible a device will have magic uniform access to memory when
> > >>> CPUs cannot.
> > >>
> > >> So it means dev_to_node() will return either NUMA_NO_NODE or a
> > >> valid node id?
> > > 
> > > NUMA_NO_NODE := -1, which is not a valid node number. It is also, like I
> > > said, not a valid device location on a NUMA system.
> > > 
> > > Just because ACPI/BIOS is shit, doesn't mean the device doesn't have a
> > > node association. It just means we don't know and might have to guess.
> > 
> > How do we guess the device's location when ACPI/BIOS does not set it?
> 
> See device_add(), it looks to the device's parent and on NO_NODE, puts
> it there.
> 
> Lacking any hints, just stick it to node0 and print a FW_BUG or
> something.
> 
> > It seems dev_to_node() does not do anything about that and leave the
> > job to the caller or whatever function that get called with its return
> > value, such as cpumask_of_node().
> 
> Well, dev_to_node() doesn't do anything; nor should it. It are the
> callers of set_dev_node() that should be taking care.
> 
> Also note how device_add() sets the device node to the parent device's
> node on NUMA_NO_NODE. Arguably we should change it to complain when it
> finds NUMA_NO_NODE and !parent.
> 
> ---
>  drivers/base/core.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index f0dd8e38fee3..2caf204966a0 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -2120,8 +2120,16 @@ int device_add(struct device *dev)
>  		dev->kobj.parent = kobj;
>  
>  	/* use parent numa_node */
> -	if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
> -		set_dev_node(dev, dev_to_node(parent));
> +	if (dev_to_node(dev) == NUMA_NO_NODE) {
> +		if (parent)
> +			set_dev_node(dev, dev_to_node(parent));
> +#ifdef CONFIG_NUMA
> +		else {
> +			pr_err("device: '%s': has no assigned NUMA node\n", dev_name(dev));
> +			set_dev_node(dev, 0);
> +		}
> +#endif

BTW., is firmware required to always provide a NUMA node on NUMA systems?

I.e. do we really want this warning on non-NUMA systems that don't assign 
NUMA nodes?

Also, even on NUMA systems, is firmware required to provide a NUMA node - 
i.e. is it in principle invalid to offer no NUMA binding?

Thanks,

	Ingo