To ensure 1:1 peer node mapping on broken BIOS node distances: node 0 1 2 3 0: 10 21 20 20 1: 21 10 20 20 2: 20 20 10 20 3: 20 20 20 10 or with numa=fake=4U node distances: node 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0: 10 10 10 10 21 21 21 21 17 17 17 17 28 28 28 28 1: 10 10 10 10 21 21 21 21 17 17 17 17 28 28 28 28 2: 10 10 10 10 21 21 21 21 17 17 17 17 28 28 28 28 3: 10 10 10 10 21 21 21 21 17 17 17 17 28 28 28 28 4: 21 21 21 21 10 10 10 10 28 28 28 28 17 17 17 17 5: 21 21 21 21 10 10 10 10 28 28 28 28 17 17 17 17 6: 21 21 21 21 10 10 10 10 28 28 28 28 17 17 17 17 7: 21 21 21 21 10 10 10 10 28 28 28 28 17 17 17 17 8: 17 17 17 17 28 28 28 28 10 10 10 10 28 28 28 28 9: 17 17 17 17 28 28 28 28 10 10 10 10 28 28 28 28 10: 17 17 17 17 28 28 28 28 10 10 10 10 28 28 28 28 11: 17 17 17 17 28 28 28 28 10 10 10 10 28 28 28 28 12: 28 28 28 28 17 17 17 17 28 28 28 28 10 10 10 10 13: 28 28 28 28 17 17 17 17 28 28 28 28 10 10 10 10 14: 28 28 28 28 17 17 17 17 28 28 28 28 10 10 10 10 15: 28 28 28 28 17 17 17 17 28 28 28 28 10 10 10 10 Signed-off-by: Fengguang Wu --- mm/page_alloc.c | 6 ++++++ 1 file changed, 6 insertions(+) --- linux.orig/mm/page_alloc.c 2018-12-23 19:48:27.366110325 +0800 +++ linux/mm/page_alloc.c 2018-12-23 19:48:27.362110332 +0800 @@ -6941,16 +6941,22 @@ static int find_best_peer_node(int nid) int n, val; int min_val = INT_MAX; int peer = NUMA_NO_NODE; + static nodemask_t target_nodes = NODE_MASK_NONE; for_each_online_node(n) { if (n == nid) continue; val = node_distance(nid, n); + if (val == LOCAL_DISTANCE) + continue; + if (node_isset(n, target_nodes)) + continue; if (val < min_val) { min_val = val; peer = n; } } + node_set(peer, target_nodes); return peer; }