slab: decouple pointer to barn from kmem_cache_node

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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).

Thus decouple the two structures. In struct kmem_cache we have an array
for kmem_cache_node pointers that appears to be sized MAX_NUMNODES but
the actual size calculation in kmem_cache_init() uses nr_node_ids.
Therefore we can't just add another array of barn pointers. Instead
change the array to newly introduced struct kmem_cache_per_node_ptrs
holding both kmem_cache_node and barn pointer.

Adjust barn accessor and allocation/initialization code accordingly. For
now no functional change intended, barns are created 1:1 together with
kmem_cache_nodes.

Link: https://patch.msgid.link/20260311-b4-slab-memoryless-barns-v1-1-70ab850be4ce@kernel.org
Signed-off-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Reviewed-by: Hao Li <hao.li@linux.dev>

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This commit is contained in:

Vlastimil Babka (SUSE) 2026-03-11 09:25:55 +01:00

parent 69d73421b7

commit 5ba6bc27b1

2 changed files with 78 additions and 57 deletions

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mm/slab.h

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130

mm/slub.c

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