From: Baoquan He bhe@redhat.com Subject: Revert "mm/vmstat.c: do not show lowmem reserve protection information of empty zone"

This reverts commit 26e7deadaae175.

Sonny reported that one of their tests started failing on the latest kernel on their Chrome OS platform. The root cause is that the above commit removed the protection line of empty zone, while the parser used in the test relies on the protection line to mark the end of each zone.

Let's revert it to avoid breaking userspace testing or applications.

Link: http://lkml.kernel.org/r/20200811075412.12872-1-bhe@redhat.com Fixes: 26e7deadaae175 ("mm/vmstat.c: do not show lowmem reserve protection information of empty zone)" Signed-off-by: Baoquan He bhe@redhat.com Reported-by: Sonny Rao sonnyrao@chromium.org Reviewed-by: David Hildenbrand david@redhat.com Acked-by: David Rientjes rientjes@google.com Cc: stable@vger.kernel.org [5.8.x] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

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

--- a/mm/vmstat.c~revert-mm-vmstatc-do-not-show-lowmem-reserve-protection-information-of-empty-zone +++ a/mm/vmstat.c @@ -1642,12 +1642,6 @@ static void zoneinfo_show_print(struct s zone->present_pages, zone_managed_pages(zone));

- /* If unpopulated, no other information is useful */ - if (!populated_zone(zone)) { - seq_putc(m, '\n'); - return; - } - seq_printf(m, "\n protection: (%ld", zone->lowmem_reserve[0]); @@ -1655,6 +1649,12 @@ static void zoneinfo_show_print(struct s seq_printf(m, ", %ld", zone->lowmem_reserve[i]); seq_putc(m, ')');

+ /* If unpopulated, no other information is useful */ + if (!populated_zone(zone)) { + seq_putc(m, '\n'); + return; + } + for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) seq_printf(m, "\n %-12s %lu", zone_stat_name(i), zone_page_state(zone, i)); _