[PATCH] mm, page_alloc: skip zone who has no managed_pages in calculate_totalreserve_pages()

Wei Yang
2018-11-12T07:14:40Z

Zone with no managed_pages doesn't contribute totalreserv_pages. And the
more nodes we have, the more empty zones there are.

This patch skip the zones to save some cycles.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
mm/page_alloc.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a919ba5cb3c8..567de15e1106 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7246,6 +7246,9 @@ static void calculate_totalreserve_pages(void)
struct zone *zone = pgdat->node_zones + i;
long max = 0;

+ if (!managed_zone(zone))
+ continue;
+
/* Find valid and maximum lowmem_reserve in the zone */
for (j = i; j < MAX_NR_ZONES; j++) {
if (zone->lowmem_reserve[j] > max)
--
2.15.1