Thread (53 messages) 53 messages, 5 authors, 2019-10-30

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

From: Yunsheng Lin <hidden>
Date: 2019-10-12 09:48:36
Also in: linux-acpi, linux-alpha, linux-pci, linux-s390, linux-sh, linuxppc-dev, lkml, sparclinux

On 2019/10/12 15:40, Greg KH wrote:
On Sat, Oct 12, 2019 at 02:17:26PM +0800, Yunsheng Lin wrote:
quoted
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:
quoted
On Fri, Oct 11, 2019 at 11:27:54AM +0800, Yunsheng Lin wrote:
quoted
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.
quoted
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.
quoted
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

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