From 904a9553d4fcdc0c7d5621f6178f0e07598701dc Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Tue, 8 Sep 2015 14:59:48 -0700 Subject: [PATCH] mm/page_alloc.c: refine the calculation of highest possible node id nr_node_ids records the highest possible node id, which is calculated by scanning the bitmap node_states[N_POSSIBLE]. Current implementation scan the bitmap from the beginning, which will scan the whole bitmap. This patch reverses the order by scanning from the end with find_last_bit(). Signed-off-by: Wei Yang Cc: Tejun Heo Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5b5240b7f642..809e27e77b3a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5478,11 +5478,9 @@ void __paginginit free_area_init_node(int nid, unsigned long *zones_size, */ void __init setup_nr_node_ids(void) { - unsigned int node; - unsigned int highest = 0; + unsigned int highest; - for_each_node_mask(node, node_possible_map) - highest = node; + highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES); nr_node_ids = highest + 1; } #endif