[RFC PATCH 4/7] vmstat counter for pages migrated across zones

[kaiyang2@cs.cmu.edu]

From: Kaiyang Zhao <kaiyang2@cs.cmu.edu>

Add a counter for the number of pages migrated across zones in vmstat

Signed-off-by: Kaiyang Zhao <zh_kaiyang@hotmail.com>
---
 include/linux/vm_event_item.h | 1 +
 mm/compaction.c               | 2 ++
 mm/vmstat.c                   | 1 +
 3 files changed, 4 insertions(+)

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 8abfa1240040..be88819085b6 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -79,6 +79,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		COMPACTSTALL, COMPACTFAIL, COMPACTSUCCESS,
 		KCOMPACTD_WAKE,
 		KCOMPACTD_MIGRATE_SCANNED, KCOMPACTD_FREE_SCANNED,
+		COMPACT_CROSS_ZONE_MIGRATED,
 #endif
 #ifdef CONFIG_HUGETLB_PAGE
 		HTLB_BUDDY_PGALLOC, HTLB_BUDDY_PGALLOC_FAIL,
diff --git a/mm/compaction.c b/mm/compaction.c
index 03b5c4debc17..dea10ad8ec64 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2552,6 +2552,8 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
 
 	count_compact_events(COMPACTMIGRATE_SCANNED, cc->total_migrate_scanned);
 	count_compact_events(COMPACTFREE_SCANNED, cc->total_free_scanned);
+	if (dst_zone != cc->zone)
+		count_compact_events(COMPACT_CROSS_ZONE_MIGRATED, nr_succeeded);
 
 	trace_mm_compaction_end(cc, start_pfn, end_pfn, sync, ret);
 
diff --git a/mm/vmstat.c b/mm/vmstat.c
index c28046371b45..98af82e65ad9 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1324,6 +1324,7 @@ const char * const vmstat_text[] = {
 	"compact_daemon_wake",
 	"compact_daemon_migrate_scanned",
 	"compact_daemon_free_scanned",
+	"compact_cross_zone_migrated",
 #endif
 
 #ifdef CONFIG_HUGETLB_PAGE
-- 
2.40.1