Commit f7ec1044 authored Jun 28, 2021 by Liu Shixin Committed by Linus Torvalds Jun 29, 2021

mm/page_alloc: fix counting of managed_pages

commit f6366156 ("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/20210527125707.3760259-1-liushixin2@huawei.com

Fixes: f6366156 ("mm/page_alloc.c: clear out zone->lowmem_reserve[] if the zone is empty")
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reported-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent e47aa905

mm/page_alloc.c

+6 −6

Original line number	Diff line number	Diff line
		@@ -8240,17 +8240,17 @@ static void setup_per_zone_lowmem_reserve(void)
		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];

		managed_pages += zone_managed_pages(upper_zone);

		if (clear)
		zone->lowmem_reserve[j] = 0;
		else
		zone->lowmem_reserve[j] = managed_pages / ratio;
		}
		}
		}
		}

		/* update totalreserve_pages */
		calculate_totalreserve_pages();