Re: [PATCH] mm/memory_hotplug: Cache auto_movable stats to optimize online check

From: David Hildenbrand (Red Hat)
Date: Thu Dec 18 2025 - 03:57:25 EST


On 12/18/25 07:41, Swaraj Gaikwad wrote:
Hi David,

Hi!


I’m just checking in on this patch to see if you’ve had a chance to review
the benchmark results I shared last week.

Not really, still traveling and this is veeeery low priority :)

To recap, the caching reduced the
execution time for the NUMA_NO_NODE case from ~2402 ns to ~453 ns in my test
environment.

Yeah, but these micro-benchmarks don't really matter ... at all. What would be interesting is what happens when you hotplug a lot of memory to a system with a lot of nodes. I suspect it won't really be a problem.


Please let me know if the performance gain justifies the change in your view,or
if you would prefer I send a v2 that simply updates the TODO comment as you suggested.

I'd prefer if things that are not a real problem would not consume my bandwidth while traveling ;)

Anyhow, there was a kernel bot complaint that you are using "struct auto_movable_stats" before the compiler knows about it (and its size).

When you resend, make sure to better describe the "why" we are doing it. It cleans up the code a little, so that could be used as an argument.

--
Cheers

David