[RFC PATCH v3 7/7] mm/damon: Add "damon_migrate_{hot,cold}" vmstat

[Honggyu Kim]

This patch adds "damon_migrate_{hot,cold}" under node specific vmstat
counters at the following location.

  /sys/devices/system/node/node*/vmstat

The counted values are accumulcated to the global vmstat so it also
introduces the same counter at /proc/vmstat as well.

Signed-off-by: Honggyu Kim <honggyu.kim@xxxxxx>
---
 include/linux/mmzone.h |  4 ++++
 mm/damon/paddr.c       | 17 ++++++++++++++++-
 mm/vmstat.c            |  4 ++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a497f189d988..0005372c5503 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -214,6 +214,10 @@ enum node_stat_item {
 	PGDEMOTE_KSWAPD,
 	PGDEMOTE_DIRECT,
 	PGDEMOTE_KHUGEPAGED,
+#ifdef CONFIG_DAMON_PADDR
+	DAMON_MIGRATE_HOT,
+	DAMON_MIGRATE_COLD,
+#endif
 	NR_VM_NODE_STAT_ITEMS
 };
 
diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c
index fd9d35b5cc83..d559c242d151 100644
--- a/mm/damon/paddr.c
+++ b/mm/damon/paddr.c
@@ -235,10 +235,23 @@ enum migration_mode {
 
 static unsigned int migrate_folio_list(struct list_head *migrate_folios,
 				       struct pglist_data *pgdat,
+				       enum migration_mode mm,
 				       int target_nid)
 {
 	unsigned int nr_succeeded;
 	nodemask_t allowed_mask = NODE_MASK_NONE;
+	enum node_stat_item node_stat;
+
+	switch (mm) {
+	case MIG_MIGRATE_HOT:
+		node_stat = DAMON_MIGRATE_HOT;
+		break;
+	case MIG_MIGRATE_COLD:
+		node_stat = DAMON_MIGRATE_COLD;
+		break;
+	default:
+		return 0;
+	}
 
 	struct migration_target_control mtc = {
 		/*
@@ -263,6 +276,8 @@ static unsigned int migrate_folio_list(struct list_head *migrate_folios,
 		      (unsigned long)&mtc, MIGRATE_ASYNC, MR_DAMON,
 		      &nr_succeeded);
 
+	mod_node_page_state(pgdat, node_stat, nr_succeeded);
+
 	return nr_succeeded;
 }
 
@@ -302,7 +317,7 @@ static unsigned int damon_pa_migrate_folio_list(struct list_head *folio_list,
 	/* 'folio_list' is always empty here */
 
 	/* Migrate folios selected for migration */
-	nr_migrated += migrate_folio_list(&migrate_folios, pgdat, target_nid);
+	nr_migrated += migrate_folio_list(&migrate_folios, pgdat, mm, target_nid);
 	/* Folios that could not be migrated are still in @migrate_folios */
 	if (!list_empty(&migrate_folios)) {
 		/* Folios which weren't migrated go back on @folio_list */
diff --git a/mm/vmstat.c b/mm/vmstat.c
index db79935e4a54..be9ba89fede1 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1252,6 +1252,10 @@ const char * const vmstat_text[] = {
 	"pgdemote_kswapd",
 	"pgdemote_direct",
 	"pgdemote_khugepaged",
+#ifdef CONFIG_DAMON_PADDR
+	"damon_migrate_hot",
+	"damon_migrate_cold",
+#endif
 
 	/* enum writeback_stat_item counters */
 	"nr_dirty_threshold",
-- 
2.34.1