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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 07215C43331 for ; Fri, 6 Sep 2019 08:22:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D8D932084F for ; Fri, 6 Sep 2019 08:22:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732683AbfIFIWu (ORCPT ); Fri, 6 Sep 2019 04:22:50 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:6692 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727376AbfIFIWt (ORCPT ); Fri, 6 Sep 2019 04:22:49 -0400 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id BA31868B9DD1DF7BB3BC; Fri, 6 Sep 2019 16:22:46 +0800 (CST) Received: from [127.0.0.1] (10.74.191.121) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.439.0; Fri, 6 Sep 2019 16:22:40 +0800 Subject: Re: [PATCH RFC] driver core: ensure a device has valid node id in device_add() To: Greg KH CC: , , , , , References: <1567647230-166903-1-git-send-email-linyunsheng@huawei.com> <20190905055727.GB23826@kroah.com> <20190905073334.GA29933@kroah.com> <5a188e2b-6c07-a9db-fbaa-561e9362d3ba@huawei.com> <20190906065211.GA18823@kroah.com> From: Yunsheng Lin Message-ID: <26d7a539-96fc-8a92-d60d-7e76e418ab63@huawei.com> Date: Fri, 6 Sep 2019 16:21:47 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20190906065211.GA18823@kroah.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.74.191.121] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/9/6 14:52, Greg KH wrote: > On Fri, Sep 06, 2019 at 02:41:36PM +0800, Yunsheng Lin wrote: >> On 2019/9/5 15:33, Greg KH wrote: >>> On Thu, Sep 05, 2019 at 02:48:24PM +0800, Yunsheng Lin wrote: >>>> On 2019/9/5 13:57, Greg KH wrote: >>>>> On Thu, Sep 05, 2019 at 09:33:50AM +0800, Yunsheng Lin wrote: >>>>>> Currently a device does not belong to any of the numa nodes >>>>>> (dev->numa_node is NUMA_NO_NODE) when the FW does not provide >>>>>> the node id and the device has not no parent device. >>>>>> >>>>>> According to discussion in [1]: >>>>>> Even if a device's numa node is not set by fw, the device >>>>>> really does belong to a node. >>>>>> >>>>>> This patch sets the device node to node 0 in device_add() if >>>>>> the fw has not specified the node id and it either has no >>>>>> parent device, or the parent device also does not have a valid >>>>>> node id. >>>>>> >>>>>> There may be explicit handling out there relying on NUMA_NO_NODE, >>>>>> like in nvme_probe(). >>>>>> >>>>>> [1] https://lkml.org/lkml/2019/9/2/466 >>>>>> >>>>>> Signed-off-by: Yunsheng Lin >>>>>> --- >>>>>> drivers/base/core.c | 17 ++++++++++++++--- >>>>>> include/linux/numa.h | 2 ++ >>>>>> 2 files changed, 16 insertions(+), 3 deletions(-) >>>>>> >>>>>> diff --git a/drivers/base/core.c b/drivers/base/core.c >>>>>> index 1669d41..466b8ff 100644 >>>>>> --- a/drivers/base/core.c >>>>>> +++ b/drivers/base/core.c >>>>>> @@ -2107,9 +2107,20 @@ int device_add(struct device *dev) >>>>>> if (kobj) >>>>>> 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)); >>>>>> + /* use parent numa_node or default node 0 */ >>>>>> + if (!numa_node_valid(dev_to_node(dev))) { >>>>>> + int nid = parent ? dev_to_node(parent) : NUMA_NO_NODE; >>>>> >>>>> Can you expand this to be a "real" if statement please? >>>> >>>> Sure. May I ask why "? :" is not appropriate here? >>> >>> Because it is a pain to read, just spell it out and make it obvious what >>> is happening. You write code for developers first, and the compiler >>> second, and in this case, either way is identical to the compiler. >>> >>>>>> + >>>>>> + if (numa_node_valid(nid)) { >>>>>> + set_dev_node(dev, nid); >>>>>> + } else { >>>>>> + if (nr_node_ids > 1U) >>>>>> + pr_err("device: '%s': has invalid NUMA node(%d)\n", >>>>>> + dev_name(dev), dev_to_node(dev)); >>>>> >>>>> dev_err() will show you the exact device properly, instead of having to >>>>> rely on dev_name(). >>>>> >>>>> And what is a user to do if this message happens? How do they fix this? >>>>> If they can not, what good is this error message? >>>> >>>> If user know about their system's topology well enough and node 0 >>>> is not the nearest node to the device, maybe user can readjust that by >>>> writing the nearest node to /sys/class/pci_bus/XXXX/device/numa_node, >>>> if not, then maybe user need to contact the vendor for info or updates. >>>> >>>> Maybe print error message as below: >>>> >>>> dev_err(dev, FW_BUG "has invalid NUMA node(%d). Readjust it by writing to sysfs numa_node or contact your vendor for updates.\n", >>>> dev_to_node(dev)); >>> >>> FW_BUG? >>> >>> Anyway, if you make this change, how many machines start reporting this >>> error? >> >> Any machines with more than one numa node will start reporting this error. >> >> 1) many virtual deivces maybe do not set the node id before calling >> device_register(), such as vfio, tun, etc. >> >> 2) struct cpu has a dev, but does not set the dev' node according to >> cpu_to_node(). >> >> 3) Many platform Device also do not have a node id provided by FW. > > Then this patch is not ok, as you are flooding the kernel log saying the > system is "broken" when this is just what it always has been like. How > is anyone going to "fix" things? cpu->node_id does not seem to be used, maybe we can fix the cpu device: diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index cc37511d..ad0a841 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -41,7 +41,7 @@ static void change_cpu_under_node(struct cpu *cpu, int cpuid = cpu->dev.id; unregister_cpu_under_node(cpuid, from_nid); register_cpu_under_node(cpuid, to_nid); - cpu->node_id = to_nid; + set_dev_node(&cpu->dev, to_nid); } static int cpu_subsys_online(struct device *dev) @@ -367,7 +367,7 @@ int register_cpu(struct cpu *cpu, int num) { int error; - cpu->node_id = cpu_to_node(num); + set_dev_node(&cpu->dev, cpu_to_node(num)); memset(&cpu->dev, 0x00, sizeof(struct device)); cpu->dev.id = num; cpu->dev.bus = &cpu_subsys; diff --git a/include/linux/cpu.h b/include/linux/cpu.h index fcb1386..9a6fc51 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -24,7 +24,6 @@ struct device_node; struct attribute_group; struct cpu { - int node_id; /* The node which contains the CPU */ int hotpluggable; /* creates sysfs control file if hotpluggable */ struct device dev; }; > > You can adjust the default node to 0 as isn't that what always has > happened, but you can not claim it is a "error" that this is happening > because it is not an error, it's just the default operation. You are right, will remove the error log.