Re: [PATCH] mm/mempolicy: recompute automatic interleave weights on memory hotplug

[Gregory Price (Meta)]

On 2026-10-27 14:04 +0100, David Hildenbrand (Arm) wrote:
> >>> +	/*
> >>> +	 * HMAT and CXL report a node's bandwidth only when it first gains
> >>> +	 * memory, so recompute the weights whenever N_MEMORY changes.
> >>> +	 */
> >>> +	wi_state_refresh();
> >>
> >> If the function fails, should we at least pr_warn_once() ?
> >>
> > 
> > The only failure state is -ENOMEM, wasn't sure that was worth warning
> > on.  I actually debated whether to just make this a void function.
> > 
> > I don't have a strong feeling here, but happy to add a warn if you
> > prefer it.
> 
> I'd assume we'd at least want to tell the world somehow that something is now
> imprecise?
> 
> Or is not updating that harmless?
> 

It's a potential performance regression, but if we just -ENOMEM'd a
kernel buffer to hold the weights, there's bigger issues.

I'll add a warn.

-- 
~Gregory