From: Christoph Lameter The alien cache is a per cpu per node array allocated for every slab on the system. Currently we size this array for all nodes that the kernel does support. For IA64 this is 1024 nodes. So we allocate an array with 1024 objects even if we only boot a system with 4 nodes. This patch uses "nr_node_ids" to determine the number of possible nodes supported by a hardware configuration and only allocates an alien cache sized for possible nodes. The initialization of nr_node_ids occurred too late relative to the bootstrap of the slab allocator and so I moved the setup_nr_node_ids() into free_area_init_nodes(). Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton --- mm/page_alloc.c | 2 +- mm/slab.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff -puN mm/page_alloc.c~slab-reduce-size-of-alien-cache-to-cover-only-possible-nodes mm/page_alloc.c --- a/mm/page_alloc.c~slab-reduce-size-of-alien-cache-to-cover-only-possible-nodes +++ a/mm/page_alloc.c @@ -2971,6 +2971,7 @@ void __init free_area_init_nodes(unsigne early_node_map[i].end_pfn); /* Initialise every node */ + setup_nr_node_ids(); for_each_online_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); free_area_init_node(nid, pgdat, NULL, @@ -3196,7 +3197,6 @@ static int __init init_per_zone_pages_mi min_free_kbytes = 65536; setup_per_zone_pages_min(); setup_per_zone_lowmem_reserve(); - setup_nr_node_ids(); return 0; } module_init(init_per_zone_pages_min) diff -puN mm/slab.c~slab-reduce-size-of-alien-cache-to-cover-only-possible-nodes mm/slab.c --- a/mm/slab.c~slab-reduce-size-of-alien-cache-to-cover-only-possible-nodes +++ a/mm/slab.c @@ -1042,7 +1042,7 @@ static void *alternate_node_alloc(struct static struct array_cache **alloc_alien_cache(int node, int limit) { struct array_cache **ac_ptr; - int memsize = sizeof(void *) * MAX_NUMNODES; + int memsize = sizeof(void *) * nr_node_ids; int i; if (limit > 1) _