Re: [PATCH 2/2 v6] mm/mempolicy: Don't create weight sysfs for memoryless nodes

[Gregory Price <gourry@gourry.net>]

On Fri, Mar 07, 2025 at 08:46:46PM +0900, Honggyu Kim wrote:
> You can see more info below.
> 
>   $ cd /sys/devices/system/node
> 
>   $ ls -d node*
>   node0  node1  node2  node3
> 
>   $ cat possible
>   0-11

We're split across two threads now, but i'll add this context

I'm basically asking whether there should be 12 nodes possible. It seems
like there should only be 4 nodes possible - 2 for sockets, 2 for host
bridges.

Unless I'm misunderstanding, it should be the case that a given physical
address can only be hosted by 1 numa node (proximity domain).

So it *should* be the case that you either have 4 nodes possible or 10
nodes possible, not 12.  But I could be missing a piece of context.

> Which command do we need for this info specifically?  My output doesn't
> provide some useful info for that.
> 
>   $ acpidump -b
>   $ iasl -d *
>   $ cat cedt.dsl
>       ...
>   **** Unknown ACPI table signature [CEDT]
>

You probably have an old version of acpidump here, you might need to get
a newer version that knows about the CEDT.

You'll also want to get all the Memory Affinity entries from srat.dsl

> Not sure about it.  This must be fixed ASAP because current kernel is
> broken on this issue and the fix should go into hotfix tree first.
>

I agree something is broken, I'm not convinced what is broken.

> If you can think this is just a bandaid, but leaving it bleeding as is
> not the right approach.
>

This affects userland, we shouldn't thrash on this. Lets get it right.

~Gregory