[v2 PATCH 8/9] mm: vmscan: add page demotion counter

Yang Shi
2019-04-11T03:57:50Z

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

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

Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
include/linux/vm_event_item.h | 2 ++
include/linux/vmstat.h | 1 +
mm/internal.h | 1 +
mm/vmscan.c | 7 +++++++
mm/vmstat.c | 2 ++
5 files changed, 13 insertions(+)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 47a3441..499a3aa 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -32,6 +32,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
PGREFILL,
PGSTEAL_KSWAPD,
PGSTEAL_DIRECT,
+ PGDEMOTE_KSWAPD,
+ PGDEMOTE_DIRECT,
PGSCAN_KSWAPD,
PGSCAN_DIRECT,
PGSCAN_DIRECT_THROTTLE,
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 2db8d60..eb5d21c 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -29,6 +29,7 @@ struct reclaim_stat {
unsigned nr_activate;
unsigned nr_ref_keep;
unsigned nr_unmap_fail;
+ unsigned nr_demoted;
};

#ifdef CONFIG_VM_EVENT_COUNTERS
diff --git a/mm/internal.h b/mm/internal.h
index 8c424b5..8ba4853 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -156,6 +156,7 @@ struct scan_control {
unsigned int immediate;
unsigned int file_taken;
unsigned int taken;
+ unsigned int demoted;
} nr;
};

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 50cde53..a52c8248 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1511,6 +1511,12 @@ static unsigned long shrink_page_list(struct list_head *page_list,

nr_reclaimed += nr_succeeded;

+ stat->nr_demoted = nr_succeeded;
+ if (current_is_kswapd())
+ __count_vm_events(PGDEMOTE_KSWAPD, stat->nr_demoted);
+ else
+ __count_vm_events(PGDEMOTE_DIRECT, stat->nr_demoted);
+
if (err) {
if (err == -ENOMEM)
set_bit(PGDAT_CONTENDED,
@@ -2019,6 +2025,7 @@ static int current_may_throttle(void)
sc->nr.unqueued_dirty += stat.nr_unqueued_dirty;
sc->nr.writeback += stat.nr_writeback;
sc->nr.immediate += stat.nr_immediate;
+ sc->nr.demoted += stat.nr_demoted;
sc->nr.taken += nr_taken;
if (file)
sc->nr.file_taken += nr_taken;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 1a431dc..d1e4993 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1192,6 +1192,8 @@ int fragmentation_index(struct zone *zone, unsigned int order)
"pgrefill",
"pgsteal_kswapd",
"pgsteal_direct",
+ "pgdemote_kswapd",
+ "pgdemote_direct",
"pgscan_kswapd",
"pgscan_direct",
"pgscan_direct_throttle",
--
1.8.3.1