LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Greg KH <gregkh@linuxfoundation.org>
To: Yunsheng Lin <linyunsheng@huawei.com>
Cc: rafael@kernel.org, linux-kernel@vger.kernel.org,
	peterz@infradead.org, mingo@kernel.org, mhocko@kernel.org,
	linuxarm@huawei.com
Subject: Re: [PATCH RFC] driver core: ensure a device has valid node id in device_add()
Date: Thu, 5 Sep 2019 07:57:27 +0200
Message-ID: <20190905055727.GB23826@kroah.com> (raw)
In-Reply-To: <1567647230-166903-1-git-send-email-linyunsheng@huawei.com>

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 <linyunsheng@huawei.com>
> ---
>  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?

> +
> +		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?

thanks,

greg k-h

  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-05  1:33 Yunsheng Lin
2019-09-05  5:57 ` Greg KH [this message]
2019-09-05  6:48   ` Yunsheng Lin
2019-09-05  7:33     ` Greg KH
2019-09-05  8:57       ` Yunsheng Lin
2019-09-05  9:02         ` Greg KH
2019-09-05  9:07           ` Yunsheng Lin
2019-09-06  6:41       ` Yunsheng Lin
2019-09-06  6:52         ` Greg KH
2019-09-06  8:21           ` Yunsheng Lin
2019-09-06 14:00             ` Greg KH
2019-09-07  2:10               ` Yunsheng Lin

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190905055727.GB23826@kroah.com \
    --to=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxarm@huawei.com \
    --cc=linyunsheng@huawei.com \
    --cc=mhocko@kernel.org \
    --cc=mingo@kernel.org \
    --cc=peterz@infradead.org \
    --cc=rafael@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git