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

Michal Hocko
2019-10-29T08:53:53Z

On Mon 28-10-19 17:20:33, Yunsheng Lin wrote:
> 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@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".
> >
> > 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.
>
> Hi, all.
>
> The warning for the above case has been added in [1].
>
> So maybe it makes sense to make node_to_cpumask_map() NUMA_NO_NODE aware
> now?
>
> If Yes, this patch still can be applied to the latest linus' tree cleanly,
> Do I need to resend it?
>

By this patch you mean http://lkml.kernel.org/r/1568724534-146242-1-git-send-email-linyunsheng@huawei.com
right?

I would just resend it unless there is still a clear disagreement over
it.

> [1] https://lore.kernel.org/linux-pci/1571467543-26125-1-git-send-email-linyunsheng@huawei.com/

--
Michal Hocko
SUSE Labs