2021-01-26 10:26:32

by Dave Hansen

[permalink] [raw]
Subject: [RFC][PATCH 09/13] mm/vmscan: add page demotion counter


From: Yang Shi <[email protected]>

Account the number of demoted pages into reclaim_state->nr_demoted.

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 <[email protected]>
Signed-off-by: Dave Hansen <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Huang Ying <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: osalvador <[email protected]>

--

Changes since 202010:
* remove unused scan-control 'demoted' field
---

b/include/linux/vm_event_item.h | 2 ++
b/mm/vmscan.c | 5 +++++
b/mm/vmstat.c | 2 ++
3 files changed, 9 insertions(+)

diff -puN include/linux/vm_event_item.h~mm-vmscan-add-page-demotion-counter include/linux/vm_event_item.h
--- a/include/linux/vm_event_item.h~mm-vmscan-add-page-demotion-counter 2021-01-25 16:23:15.821866693 -0800
+++ b/include/linux/vm_event_item.h 2021-01-25 16:23:15.831866693 -0800
@@ -33,6 +33,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
PGREUSE,
PGSTEAL_KSWAPD,
PGSTEAL_DIRECT,
+ PGDEMOTE_KSWAPD,
+ PGDEMOTE_DIRECT,
PGSCAN_KSWAPD,
PGSCAN_DIRECT,
PGSCAN_DIRECT_THROTTLE,
diff -puN mm/vmscan.c~mm-vmscan-add-page-demotion-counter mm/vmscan.c
--- a/mm/vmscan.c~mm-vmscan-add-page-demotion-counter 2021-01-25 16:23:15.823866693 -0800
+++ b/mm/vmscan.c 2021-01-25 16:23:15.835866693 -0800
@@ -1120,6 +1120,11 @@ static unsigned int demote_page_list(str
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 -puN mm/vmstat.c~mm-vmscan-add-page-demotion-counter mm/vmstat.c
--- a/mm/vmstat.c~mm-vmscan-add-page-demotion-counter 2021-01-25 16:23:15.825866693 -0800
+++ b/mm/vmstat.c 2021-01-25 16:23:15.838866693 -0800
@@ -1244,6 +1244,8 @@ const char * const vmstat_text[] = {
"pgreuse",
"pgsteal_kswapd",
"pgsteal_direct",
+ "pgdemote_kswapd",
+ "pgdemote_direct",
"pgscan_kswapd",
"pgscan_direct",
"pgscan_direct_throttle",
_