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

[Yunsheng Lin]

On 2019/10/12 15:40, Greg KH wrote:
> On Sat, Oct 12, 2019 at 02:17:26PM +0800, Yunsheng Lin wrote:
>> add pci and acpi maintainer
>> cc linux-pci@xxxxxxxxxxxxxxx and linux-acpi@xxxxxxxxxxxxxxx
>>
>> 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".
> 
> If the firmware of a pci device does not provide the node information,
> then yes, warn about that.
> 
>> 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?
> 
> Say it is a firmware bug, if it is a firmware bug, that's simple.
> 
>> If this kind of reporting is common pratice and will not cause any
>> misunderstanding, then maybe we can report that.
> 
> Yes, please do so, that's the only way those boxes are ever going to get
> fixed.  And go add the test to the "firmware testing" tool that is based
> on Linux that Intel has somewhere, to give vendors a chance to fix this
> before they ship hardware.
> 
> This shouldn't be a big deal, we warn of other hardware bugs all the
> time.

Ok, thanks for clarifying.

Will send a patch to catch the case when a pcie device without numa node
being set and warn about it.

Maybe use dev->bus to verify if it is a pci device?

> 
> thanks,
> 
> greg k-h
> 
> .
>