[RFC -V4 6/6] autonuma, memory tiering: Add page promotion counter

[Huang Ying <ying.huang@intel.com>]

To distinguish the number of promotion from the original inter-socket
NUMA balancing migration.  The counter is per-node (target node).
This is to identify imbalance among NUMA nodes.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
---
 include/linux/mmzone.h |  1 +
 mm/migrate.c           | 10 +++++++++-
 mm/vmstat.c            |  1 +
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index c10efdc92b17..b384489897b7 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -209,6 +209,7 @@ enum node_stat_item {
 #endif
 #ifdef CONFIG_NUMA_BALANCING
 	PGPROMOTE_CANDIDATE,	/* candidate pages to promote */
+	PGPROMOTE_SUCCESS,	/* promote successfully */
 #endif
 	NR_VM_NODE_STAT_ITEMS
 };
diff --git a/mm/migrate.c b/mm/migrate.c
index d8d80b111a6a..0f4106b6c4fe 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2161,8 +2161,13 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
 			putback_lru_page(page);
 		}
 		isolated = 0;
-	} else
+	} else {
 		count_vm_numa_event(NUMA_PAGE_MIGRATE);
+		if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
+		    !node_is_toptier(page_to_nid(page)) && node_is_toptier(node))
+			mod_node_page_state(NODE_DATA(node), PGPROMOTE_SUCCESS,
+					    nr_succeeded);
+	}
 	BUG_ON(!list_empty(&migratepages));
 	return isolated;
 
@@ -2287,6 +2292,9 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 	mod_node_page_state(page_pgdat(page),
 			NR_ISOLATED_ANON + page_lru,
 			-HPAGE_PMD_NR);
+	if (!node_is_toptier(page_to_nid(page)) && node_is_toptier(node))
+		mod_node_page_state(NODE_DATA(node), PGPROMOTE_SUCCESS,
+				    HPAGE_PMD_NR);
 	return isolated;
 
 out_fail:
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 2e60cc0232ef..ba5f6f987711 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1217,6 +1217,7 @@ const char * const vmstat_text[] = {
 #endif
 #ifdef CONFIG_NUMA_BALANCING
 	"pgpromote_candidate",
+	"pgpromote_success",
 #endif
 
 	/* enum writeback_stat_item counters */
-- 
2.28.0