Re: [PATCH v2 0/2] handle memoryless nodes more appropriately

[Qi Zheng]

Hi David,

On 2023/10/19 15:56, David Hildenbrand wrote:
> On 19.10.23 09:36, Qi Zheng wrote:
> > Hi all,
> >
> > Currently, in the process of initialization or offline memory, memoryless
> > nodes will still be built into the fallback list of itself or other 
> > nodes.
> >
> > This is not what we expected, so this patch series removes memoryless
> > nodes from the fallback list entirely.
>
> What's the end result of this change -- IOW why do we care? Patch #1 
> mentions "which will reduce runtime overhead." and patch #2 mentions 
> "This will incur some runtime overhead.". IIUC the comment in patch #1 
> correctly, these changes don't fix anything, correct?

Yes, after dropping the NODE_MIN_SIZE constrain in x86, the panic
problem fixed by this patch no longer exists (Unless there are other
architectures that have this constrain).

The reason I am re-sending this patch is that I agree with Ingo's point
of view:

```
While I agree with dropping the limitation, and I agree that
9391a3f9c7f1 should have provided more of a justification, I believe a
core MM fix is in order as well, for it to not crash.
```

I also think that core MM should be safe (not crash) even in some weird
topology.

> Did you look into showing a performance gain?

No, and I think the performance gain should be small, after all it just
traverses one less node. ;)

Thanks,
Qi