[178/192] mm/page_alloc: fix counting of managed_pages

Commit Message

Andrew Morton June 29, 2021, 2:42 a.m. UTC

From: Liu Shixin <[e-mail]>
Subject: mm/page_alloc: fix counting of managed_pages

commit f63661566fad ("mm/page_alloc.c: clear out zone->lowmem_reserve[] if
the zone is empty") clears out zone->lowmem_reserve[] if zone is empty. 
But when zone is not empty and sysctl_lowmem_reserve_ratio[i] is set to
zero, zone_managed_pages(zone) is not counted in the managed_pages either.
This is inconsistent with the description of lowmem_reserve, so fix it.

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: f63661566fad ("mm/page_alloc.c: clear out zone->lowmem_reserve[] if the zone is empty")
Signed-off-by: Liu Shixin <[e-mail]>
Reported-by: yangerkun <[e-mail]>
Reviewed-by: Baoquan He <[e-mail]>
Acked-by: David Hildenbrand <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/page_alloc.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Patch

--- a/mm/page_alloc.c~mm-page_alloc-fix-counting-of-managed_pages
+++ a/mm/page_alloc.c
@@ -8240,14 +8240,14 @@  static void setup_per_zone_lowmem_reserv
 			unsigned long managed_pages = 0;
 
 			for (j = i + 1; j < MAX_NR_ZONES; j++) {
-				if (clear) {
-					zone->lowmem_reserve[j] = 0;
-				} else {
-					struct zone *upper_zone = &pgdat->node_zones[j];
+				struct zone *upper_zone = &pgdat->node_zones[j];
+
+				managed_pages += zone_managed_pages(upper_zone);
 
-					managed_pages += zone_managed_pages(upper_zone);
+				if (clear)
+					zone->lowmem_reserve[j] = 0;
+				else
 					zone->lowmem_reserve[j] = managed_pages / ratio;
-				}
 			}
 		}
 	}