Add vmstat counter to track scanning, migration and
type of pages.

Signed-off-by: Raghavendra K T <raghavendra.kt@amd.com>
---
 include/linux/mm.h            | 13 ++++++++
 include/linux/vm_event_item.h | 12 +++++++
 mm/kscand.c                   | 63 +++++++++++++++++++++++++++++++++--
 mm/vmstat.c                   | 12 +++++++
 4 files changed, 98 insertions(+), 2 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index fa538feaa8d9..0d579d0294bf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -655,6 +655,19 @@ struct vm_operations_struct {
 					  unsigned long addr);
 };
 
+#ifdef CONFIG_KSCAND
+void count_kscand_mm_scans(void);
+void count_kscand_vma_scans(void);
+void count_kscand_migadded(void);
+void count_kscand_migrated(void);
+void count_kscand_migrate_failed(void);
+void count_kscand_slowtier(void);
+void count_kscand_toptier(void);
+void count_kscand_idlepage(void);
+void count_kscand_hotpage(void);
+void count_kscand_coldpage(void);
+#endif
+
 #ifdef CONFIG_NUMA_BALANCING
 static inline void vma_numab_state_init(struct vm_area_struct *vma)
 {
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 9e15a088ba38..b5643be5dd94 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -67,6 +67,18 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		NUMA_HINT_FAULTS_LOCAL,
 		NUMA_PAGE_MIGRATE,
 #endif
+#ifdef CONFIG_KSCAND
+		KSCAND_MM_SCANS,
+		KSCAND_VMA_SCANS,
+		KSCAND_MIGADDED,
+		KSCAND_MIGRATED,
+		KSCAND_MIGRATE_FAILED,
+		KSCAND_SLOWTIER,
+		KSCAND_TOPTIER,
+		KSCAND_IDLEPAGE,
+		KSCAND_HOTPAGE,
+		KSCAND_COLDPAGE,
+#endif
 #ifdef CONFIG_MIGRATION
 		PGMIGRATE_SUCCESS, PGMIGRATE_FAIL,
 		THP_MIGRATION_SUCCESS,
diff --git a/mm/kscand.c b/mm/kscand.c
index a73606f7ca3c..e14645565ba7 100644
--- a/mm/kscand.c
+++ b/mm/kscand.c
@@ -339,6 +339,47 @@ struct attribute_group kscand_attr_group = {
 };
 #endif
 
+void count_kscand_mm_scans(void)
+{
+	count_vm_numa_event(KSCAND_MM_SCANS);
+}
+void count_kscand_vma_scans(void)
+{
+	count_vm_numa_event(KSCAND_VMA_SCANS);
+}
+void count_kscand_migadded(void)
+{
+	count_vm_numa_event(KSCAND_MIGADDED);
+}
+void count_kscand_migrated(void)
+{
+	count_vm_numa_event(KSCAND_MIGRATED);
+}
+void count_kscand_migrate_failed(void)
+{
+	count_vm_numa_event(KSCAND_MIGRATE_FAILED);
+}
+void count_kscand_slowtier(void)
+{
+	count_vm_numa_event(KSCAND_SLOWTIER);
+}
+void count_kscand_toptier(void)
+{
+	count_vm_numa_event(KSCAND_TOPTIER);
+}
+void count_kscand_idlepage(void)
+{
+	count_vm_numa_event(KSCAND_IDLEPAGE);
+}
+void count_kscand_hotpage(void)
+{
+	count_vm_numa_event(KSCAND_HOTPAGE);
+}
+void count_kscand_coldpage(void)
+{
+	count_vm_numa_event(KSCAND_COLDPAGE);
+}
+
 static inline int kscand_has_work(void)
 {
 	return !list_empty(&kscand_scan.mm_head);
@@ -653,6 +694,8 @@ static int kmigrated_promote_folio(struct kscand_migrate_info *info,
 
 	if (!is_hot_page(folio))
 		return KSCAND_NOT_HOT_PAGE;
+	else
+		count_kscand_hotpage();
 
 	folio_get(folio);
 
@@ -803,12 +846,15 @@ static int hot_vma_idle_pte_entry(pte_t *pte,
 	}
 
 	if (!kscand_eligible_srcnid(srcnid)) {
+		count_kscand_toptier();
 		if (folio_test_young(folio) || folio_test_referenced(folio)
 				|| pte_young(pteval)) {
 			scanctrl->nodeinfo[srcnid]->nr_accessed++;
 		}
 		folio_put(folio);
 		return 0;
+	} else {
+		count_kscand_slowtier();
 	}
 	if (!folio_test_idle(folio) && !prev_idle &&
 		(folio_test_young(folio) || folio_test_referenced(folio))) {
@@ -820,7 +866,14 @@ static int hot_vma_idle_pte_entry(pte_t *pte,
 			info->pfn = folio_pfn(folio);
 			info->address = addr;
 			list_add_tail(&info->migrate_node, &scanctrl->scan_list);
+			count_kscand_migadded();
 		}
+		folio_put(folio);
+		return 0;
+	} else {
+		if (prev_idle)
+			count_kscand_coldpage();
+		count_kscand_idlepage();
 	}
 
 	folio_put(folio);
@@ -1045,10 +1098,13 @@ static void kmigrated_migrate_mm(struct kmigrated_mm_slot *mm_slot)
 			mstat_counter--;
 
 			/* TBD: encode migrated count here, currently assume folio_nr_pages */
-			if (!ret)
+			if (!ret) {
+				count_kscand_migrated();
 				msuccess++;
-			else
+			} else {
+				count_kscand_migrate_failed();
 				mfailed++;
+			}
 
 			kfree(info);
 
@@ -1269,6 +1325,7 @@ static unsigned long kscand_scan_mm_slot(void)
 
 	for_each_vma(vmi, vma) {
 		kscand_walk_page_vma(vma, &kscand_scanctrl);
+		count_kscand_vma_scans();
 		vma_scanned_size += vma->vm_end - vma->vm_start;
 
 		if (vma_scanned_size >= mm_slot_scan_size ||
@@ -1304,6 +1361,8 @@ static unsigned long kscand_scan_mm_slot(void)
 
 	update_mmslot_info = true;
 
+	count_kscand_mm_scans();
+
 	total = get_slowtier_accesed(&kscand_scanctrl);
 	target_node = get_target_node(&kscand_scanctrl);
 
diff --git a/mm/vmstat.c b/mm/vmstat.c
index a78d70ddeacd..5ba82d2ffe71 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1347,6 +1347,18 @@ const char * const vmstat_text[] = {
 	"numa_hint_faults_local",
 	"numa_pages_migrated",
 #endif
+#ifdef CONFIG_KSCAND
+	"nr_kscand_mm_scans",
+	"nr_kscand_vma_scans",
+	"nr_kscand_migadded",
+	"nr_kscand_migrated",
+	"nr_kscand_migrate_failed",
+	"nr_kscand_slowtier",
+	"nr_kscand_toptier",
+	"nr_kscand_idlepage",
+	"nr_kscand_hotpage",
+	"nr_kscand_coldpage",
+#endif
 #ifdef CONFIG_MIGRATION
 	"pgmigrate_success",
 	"pgmigrate_fail",
-- 
2.34.1