Re: [PATCH 1/3] slab: decouple pointer to barn from kmem_cache_node

[Christoph Lameter (Ampere)]

On Wed, 11 Mar 2026, Vlastimil Babka (SUSE) wrote:

> The pointer to barn currently exists in struct kmem_cache_node. That
> struct is instantiated for every NUMA node with memory, but we want to
> have a barn for every online node (including memoryless).

Is this breaking the 1-1 association of kmem_cache to numa
nodes? I would think you needd local per cpu queues on a memoryless node
for performance but not fake node structures. Per node access is already
serialized via locks and therefore slow.

If you break the association of per cpu queues to cpu and kmem_cache_node
to numa_nodes then the code may get complicated.