[PATCH -V9 5/9] mm/vmscan: add page demotion counter

From: Huang Ying
Date: Fri Jun 25 2021 - 03:33:38 EST


From: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>

Account the number of demoted pages.

Add pgdemote_kswapd and pgdemote_direct VM counters showed in
/proc/vmstat.

[ daveh:
- __count_vm_events() a bit, and made them look at the THP
size directly rather than getting data from migrate_pages()
]

Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
Reviewed-by: Wei Xu <weixugc@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: osalvador <osalvador@xxxxxxx>

--

Changes since 202010:
* remove unused scan-control 'demoted' field
---
include/linux/vm_event_item.h | 2 ++
mm/vmscan.c | 5 +++++
mm/vmstat.c | 2 ++
3 files changed, 9 insertions(+)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index ae0dd1948c2b..a185cc75ff52 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -33,6 +33,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
PGREUSE,
PGSTEAL_KSWAPD,
PGSTEAL_DIRECT,
+ PGDEMOTE_KSWAPD,
+ PGDEMOTE_DIRECT,
PGSCAN_KSWAPD,
PGSCAN_DIRECT,
PGSCAN_DIRECT_THROTTLE,
diff --git a/mm/vmscan.c b/mm/vmscan.c
index badaf3d4360d..78b3bae71520 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1326,6 +1326,11 @@ static unsigned int demote_page_list(struct list_head *demote_pages,
target_nid, MIGRATE_ASYNC, MR_DEMOTION,
&nr_succeeded);

+ if (current_is_kswapd())
+ __count_vm_events(PGDEMOTE_KSWAPD, nr_succeeded);
+ else
+ __count_vm_events(PGDEMOTE_DIRECT, nr_succeeded);
+
return nr_succeeded;
}

diff --git a/mm/vmstat.c b/mm/vmstat.c
index cccee36b289c..a51fbdcadff5 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1259,6 +1259,8 @@ const char * const vmstat_text[] = {
"pgreuse",
"pgsteal_kswapd",
"pgsteal_direct",
+ "pgdemote_kswapd",
+ "pgdemote_direct",
"pgscan_kswapd",
"pgscan_direct",
"pgscan_direct_throttle",
--
2.30.2