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 reverse the order by scanning from the end with find_last_bit().
Signed-off-by: Wei Yang <weiyang@xxxxxxxxxxxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: Tejun Heo <tj@xxxxxxxxxx>
---
v3:
remove the unused variable node.
v2:
Just call find_last_bit() on node_possible_map.
---
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 59248f4..c635e80 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5449,11 +5449,9 @@ 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
--
1.7.9.5
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