[PATCH 2/2] mm: move pgscan and pgsteal to node stats
From: JP Kobryn
Date: Thu Feb 12 2026 - 01:40:21 EST
It would be useful to narrow down reclaim to specific nodes.
Provide per-node reclaim visibility by changing the pgscan and pgsteal
stats from global vm_event_item's to node_stat_item's. Note this change has
the side effect of now tracking these stats on a per-memcg basis.
Signed-off-by: JP Kobryn <inwardvessel@xxxxxxxxx>
Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
drivers/virtio/virtio_balloon.c | 8 ++++----
include/linux/mmzone.h | 12 +++++++++++
include/linux/vm_event_item.h | 12 -----------
mm/memcontrol.c | 36 ++++++++++++++++++---------------
mm/vmscan.c | 32 +++++++++++------------------
mm/vmstat.c | 24 +++++++++++-----------
6 files changed, 60 insertions(+), 64 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 74fe59f5a78c..1341d9d1a2a1 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -374,13 +374,13 @@ static inline unsigned int update_balloon_vm_stats(struct virtio_balloon *vb)
update_stat(vb, idx++, VIRTIO_BALLOON_S_ALLOC_STALL, stall);
update_stat(vb, idx++, VIRTIO_BALLOON_S_ASYNC_SCAN,
- pages_to_bytes(events[PGSCAN_KSWAPD]));
+ pages_to_bytes(global_node_page_state(PGSCAN_KSWAPD)));
update_stat(vb, idx++, VIRTIO_BALLOON_S_DIRECT_SCAN,
- pages_to_bytes(events[PGSCAN_DIRECT]));
+ pages_to_bytes(global_node_page_state(PGSCAN_DIRECT)));
update_stat(vb, idx++, VIRTIO_BALLOON_S_ASYNC_RECLAIM,
- pages_to_bytes(events[PGSTEAL_KSWAPD]));
+ pages_to_bytes(global_node_page_state(PGSTEAL_KSWAPD)));
update_stat(vb, idx++, VIRTIO_BALLOON_S_DIRECT_RECLAIM,
- pages_to_bytes(events[PGSTEAL_DIRECT]));
+ pages_to_bytes(global_node_page_state(PGSTEAL_DIRECT)));
#ifdef CONFIG_HUGETLB_PAGE
update_stat(vb, idx++, VIRTIO_BALLOON_S_HTLB_PGALLOC,
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 762609d5f0af..fc39c107a4b5 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -255,6 +255,18 @@ enum node_stat_item {
PGDEMOTE_DIRECT,
PGDEMOTE_KHUGEPAGED,
PGDEMOTE_PROACTIVE,
+ PGSTEAL_KSWAPD,
+ PGSTEAL_DIRECT,
+ PGSTEAL_KHUGEPAGED,
+ PGSTEAL_PROACTIVE,
+ PGSTEAL_ANON,
+ PGSTEAL_FILE,
+ PGSCAN_KSWAPD,
+ PGSCAN_DIRECT,
+ PGSCAN_KHUGEPAGED,
+ PGSCAN_PROACTIVE,
+ PGSCAN_ANON,
+ PGSCAN_FILE,
#ifdef CONFIG_NUMA
PGALLOC_MPOL_DEFAULT,
PGALLOC_MPOL_PREFERRED,
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 92f80b4d69a6..6f1787680658 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -40,19 +40,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
PGLAZYFREED,
PGREFILL,
PGREUSE,
- PGSTEAL_KSWAPD,
- PGSTEAL_DIRECT,
- PGSTEAL_KHUGEPAGED,
- PGSTEAL_PROACTIVE,
- PGSCAN_KSWAPD,
- PGSCAN_DIRECT,
- PGSCAN_KHUGEPAGED,
- PGSCAN_PROACTIVE,
PGSCAN_DIRECT_THROTTLE,
- PGSCAN_ANON,
- PGSCAN_FILE,
- PGSTEAL_ANON,
- PGSTEAL_FILE,
#ifdef CONFIG_NUMA
PGSCAN_ZONE_RECLAIM_SUCCESS,
PGSCAN_ZONE_RECLAIM_FAILED,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 86f43b7e5f71..bde0b6536be6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -328,6 +328,18 @@ static const unsigned int memcg_node_stat_items[] = {
PGDEMOTE_DIRECT,
PGDEMOTE_KHUGEPAGED,
PGDEMOTE_PROACTIVE,
+ PGSTEAL_KSWAPD,
+ PGSTEAL_DIRECT,
+ PGSTEAL_KHUGEPAGED,
+ PGSTEAL_PROACTIVE,
+ PGSTEAL_ANON,
+ PGSTEAL_FILE,
+ PGSCAN_KSWAPD,
+ PGSCAN_DIRECT,
+ PGSCAN_KHUGEPAGED,
+ PGSCAN_PROACTIVE,
+ PGSCAN_ANON,
+ PGSCAN_FILE,
#ifdef CONFIG_HUGETLB_PAGE
NR_HUGETLB,
#endif
@@ -441,14 +453,6 @@ static const unsigned int memcg_vm_event_stat[] = {
#endif
PSWPIN,
PSWPOUT,
- PGSCAN_KSWAPD,
- PGSCAN_DIRECT,
- PGSCAN_KHUGEPAGED,
- PGSCAN_PROACTIVE,
- PGSTEAL_KSWAPD,
- PGSTEAL_DIRECT,
- PGSTEAL_KHUGEPAGED,
- PGSTEAL_PROACTIVE,
PGFAULT,
PGMAJFAULT,
PGREFILL,
@@ -1496,15 +1500,15 @@ static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
/* Accumulated memory events */
seq_buf_printf(s, "pgscan %lu\n",
- memcg_events(memcg, PGSCAN_KSWAPD) +
- memcg_events(memcg, PGSCAN_DIRECT) +
- memcg_events(memcg, PGSCAN_PROACTIVE) +
- memcg_events(memcg, PGSCAN_KHUGEPAGED));
+ memcg_page_state(memcg, PGSCAN_KSWAPD) +
+ memcg_page_state(memcg, PGSCAN_DIRECT) +
+ memcg_page_state(memcg, PGSCAN_PROACTIVE) +
+ memcg_page_state(memcg, PGSCAN_KHUGEPAGED));
seq_buf_printf(s, "pgsteal %lu\n",
- memcg_events(memcg, PGSTEAL_KSWAPD) +
- memcg_events(memcg, PGSTEAL_DIRECT) +
- memcg_events(memcg, PGSTEAL_PROACTIVE) +
- memcg_events(memcg, PGSTEAL_KHUGEPAGED));
+ memcg_page_state(memcg, PGSTEAL_KSWAPD) +
+ memcg_page_state(memcg, PGSTEAL_DIRECT) +
+ memcg_page_state(memcg, PGSTEAL_PROACTIVE) +
+ memcg_page_state(memcg, PGSTEAL_KHUGEPAGED));
for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++) {
#ifdef CONFIG_MEMCG_V1
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 614ccf39fe3f..16a0f21e3ea1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1977,7 +1977,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
unsigned long nr_taken;
struct reclaim_stat stat;
bool file = is_file_lru(lru);
- enum vm_event_item item;
+ enum node_stat_item item;
struct pglist_data *pgdat = lruvec_pgdat(lruvec);
bool stalled = false;
@@ -2003,10 +2003,8 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, nr_taken);
item = PGSCAN_KSWAPD + reclaimer_offset(sc);
- if (!cgroup_reclaim(sc))
- __count_vm_events(item, nr_scanned);
- count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
- __count_vm_events(PGSCAN_ANON + file, nr_scanned);
+ mod_lruvec_state(lruvec, item, nr_scanned);
+ mod_lruvec_state(lruvec, PGSCAN_ANON + file, nr_scanned);
spin_unlock_irq(&lruvec->lru_lock);
@@ -2023,10 +2021,8 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
stat.nr_demoted);
__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
item = PGSTEAL_KSWAPD + reclaimer_offset(sc);
- if (!cgroup_reclaim(sc))
- __count_vm_events(item, nr_reclaimed);
- count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
- __count_vm_events(PGSTEAL_ANON + file, nr_reclaimed);
+ mod_lruvec_state(lruvec, item, nr_reclaimed);
+ mod_lruvec_state(lruvec, PGSTEAL_ANON + file, nr_reclaimed);
lru_note_cost_unlock_irq(lruvec, file, stat.nr_pageout,
nr_scanned - nr_reclaimed);
@@ -4536,7 +4532,7 @@ static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
{
int i;
int gen;
- enum vm_event_item item;
+ enum node_stat_item item;
int sorted = 0;
int scanned = 0;
int isolated = 0;
@@ -4595,13 +4591,11 @@ static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
}
item = PGSCAN_KSWAPD + reclaimer_offset(sc);
- if (!cgroup_reclaim(sc)) {
- __count_vm_events(item, isolated);
+ if (!cgroup_reclaim(sc))
__count_vm_events(PGREFILL, sorted);
- }
- count_memcg_events(memcg, item, isolated);
+ mod_lruvec_state(lruvec, item, isolated);
count_memcg_events(memcg, PGREFILL, sorted);
- __count_vm_events(PGSCAN_ANON + type, isolated);
+ mod_lruvec_state(lruvec, PGSCAN_ANON + type, isolated);
trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, scan_batch,
scanned, skipped, isolated,
type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);
@@ -4686,7 +4680,7 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
LIST_HEAD(clean);
struct folio *folio;
struct folio *next;
- enum vm_event_item item;
+ enum node_stat_item item;
struct reclaim_stat stat;
struct lru_gen_mm_walk *walk;
bool skip_retry = false;
@@ -4750,10 +4744,8 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
stat.nr_demoted);
item = PGSTEAL_KSWAPD + reclaimer_offset(sc);
- if (!cgroup_reclaim(sc))
- __count_vm_events(item, reclaimed);
- count_memcg_events(memcg, item, reclaimed);
- __count_vm_events(PGSTEAL_ANON + type, reclaimed);
+ mod_lruvec_state(lruvec, item, reclaimed);
+ mod_lruvec_state(lruvec, PGSTEAL_ANON + type, reclaimed);
spin_unlock_irq(&lruvec->lru_lock);
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 74e0ddde1e93..e4b259989d58 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1291,6 +1291,18 @@ const char * const vmstat_text[] = {
[I(PGDEMOTE_DIRECT)] = "pgdemote_direct",
[I(PGDEMOTE_KHUGEPAGED)] = "pgdemote_khugepaged",
[I(PGDEMOTE_PROACTIVE)] = "pgdemote_proactive",
+ [I(PGSTEAL_KSWAPD)] = "pgsteal_kswapd",
+ [I(PGSTEAL_DIRECT)] = "pgsteal_direct",
+ [I(PGSTEAL_KHUGEPAGED)] = "pgsteal_khugepaged",
+ [I(PGSTEAL_PROACTIVE)] = "pgsteal_proactive",
+ [I(PGSTEAL_ANON)] = "pgsteal_anon",
+ [I(PGSTEAL_FILE)] = "pgsteal_file",
+ [I(PGSCAN_KSWAPD)] = "pgscan_kswapd",
+ [I(PGSCAN_DIRECT)] = "pgscan_direct",
+ [I(PGSCAN_KHUGEPAGED)] = "pgscan_khugepaged",
+ [I(PGSCAN_PROACTIVE)] = "pgscan_proactive",
+ [I(PGSCAN_ANON)] = "pgscan_anon",
+ [I(PGSCAN_FILE)] = "pgscan_file",
#ifdef CONFIG_NUMA
[I(PGALLOC_MPOL_DEFAULT)] = "pgalloc_mpol_default",
[I(PGALLOC_MPOL_PREFERRED)] = "pgalloc_mpol_preferred",
@@ -1344,19 +1356,7 @@ const char * const vmstat_text[] = {
[I(PGREFILL)] = "pgrefill",
[I(PGREUSE)] = "pgreuse",
- [I(PGSTEAL_KSWAPD)] = "pgsteal_kswapd",
- [I(PGSTEAL_DIRECT)] = "pgsteal_direct",
- [I(PGSTEAL_KHUGEPAGED)] = "pgsteal_khugepaged",
- [I(PGSTEAL_PROACTIVE)] = "pgsteal_proactive",
- [I(PGSCAN_KSWAPD)] = "pgscan_kswapd",
- [I(PGSCAN_DIRECT)] = "pgscan_direct",
- [I(PGSCAN_KHUGEPAGED)] = "pgscan_khugepaged",
- [I(PGSCAN_PROACTIVE)] = "pgscan_proactive",
[I(PGSCAN_DIRECT_THROTTLE)] = "pgscan_direct_throttle",
- [I(PGSCAN_ANON)] = "pgscan_anon",
- [I(PGSCAN_FILE)] = "pgscan_file",
- [I(PGSTEAL_ANON)] = "pgsteal_anon",
- [I(PGSTEAL_FILE)] = "pgsteal_file",
#ifdef CONFIG_NUMA
[I(PGSCAN_ZONE_RECLAIM_SUCCESS)] = "zone_reclaim_success",
--
2.47.3