[173/227] mm/memory_hotplug: avoid calling zone_intersects() for ZONE_NORMAL

Commit Message

Andrew Morton March 22, 2022, 9:47 p.m. UTC

From: Miaohe Lin <[e-mail]>
Subject: mm/memory_hotplug: avoid calling zone_intersects() for ZONE_NORMAL

If zid reaches ZONE_NORMAL, the caller will always get the NORMAL zone no
matter what zone_intersects() returns.  So we can save some possible cpu
cycles by avoid calling zone_intersects() for ZONE_NORMAL.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Miaohe Lin <[e-mail]>
Reviewed-by: David Hildenbrand <[e-mail]>
Reviewed-by: Oscar Salvador <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/memory_hotplug.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

--- a/mm/memory_hotplug.c~mm-memory_hotplug-avoid-calling-zone_intersects-for-zone_normal
+++ a/mm/memory_hotplug.c
@@ -823,7 +823,7 @@  static struct zone *default_kernel_zone_
 	struct pglist_data *pgdat = NODE_DATA(nid);
 	int zid;
 
-	for (zid = 0; zid <= ZONE_NORMAL; zid++) {
+	for (zid = 0; zid < ZONE_NORMAL; zid++) {
 		struct zone *zone = &pgdat->node_zones[zid];
 
 		if (zone_intersects(zone, start_pfn, nr_pages))