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 <weiyang@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Wei Yang 2015-09-08 14:59:48 -07:00 committed by Linus Torvalds
parent 52a2b53ffd
commit 904a9553d4

View File

@ -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