Re: [PATCH v6] numa: make node_to_cpumask_map() NUMA_NO_NODE aware

Yunsheng Lin
2019-10-12T06:18:01Z

add pci and acpi maintainer
cc linux-pci@vger.kernel.org and linux-acpi@vger.kernel.org

On 2019/10/11 19:15, Peter Zijlstra wrote:
> On Fri, Oct 11, 2019 at 11:27:54AM +0800, Yunsheng Lin wrote:
>> But I failed to see why the above is related to making node_to_cpumask_map()
>> NUMA_NO_NODE aware?
>
> Your initial bug is for hns3, which is a PCI device, which really _MUST_
> have a node assigned.
>
> It not having one, is a straight up bug. We must not silently accept
> NO_NODE there, ever.
>

I suppose you mean reporting a lack of affinity when the node of a pcie
device is not set by "not silently accept NO_NODE".

As Greg has asked about in [1]:
what is a user to do when the user sees the kernel reporting that?

We may tell user to contact their vendor for info or updates about
that when they do not know about their system well enough, but their
vendor may get away with this by quoting ACPI spec as the spec
considering this optional. Should the user believe this is indeed a
fw bug or a misreport from the kernel?

If this kind of reporting is common pratice and will not cause any
misunderstanding, then maybe we can report that.

[1] https://lore.kernel.org/lkml/20190905055727.GB23826@kroah.com/

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