Re: [PATCH v3 1/3] mm,slub: Do not special case N_NORMAL nodes for slab_nodes

[Vlastimil Babka <vbabka@suse.cz>]

On 5/2/25 10:36, Oscar Salvador wrote:
> Currently, slab_mem_going_going_callback() checks whether the node has
> N_NORMAL memory in order to be set in slab_nodes.
> While it is true that gettind rid of that enforcing would mean
> ending up with movables nodes in slab_nodes, the memory waste that comes
> with that is negligible.
> 
> So stop checking for status_change_nid_normal and just use status_change_nid
> instead which works for both types of memory.
> 
> Also, once we allocate the kmem_cache_node cache  for the node in

					     ^ object? instance?

> slab_mem_online_callback(), we never deallocate it in
> slab_mem_off_callback() when the node goes memoryless, so we can just
> get rid of it.
> 
> The only side effect is that we will stop clearing the node from slab_nodes.

Technically, another effect is that also any newly created kmem caches after
 node hotremove will now allocate their kmem_cache_node for the node(s) that
was hotremoved. But that should be even more negligible waste than from
using N_MEMORY.

> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Oscar Salvador <osalvador@suse.de>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>