mm/migrate: add nr_split to trace_mm_migrate_pages stats.

Add nr_split to trace_mm_migrate_pages for large folio (including THP)
split events.

[akpm@linux-foundation.org: cleanup per Huang, Ying]
Link: https://lkml.kernel.org/r/20231017163129.2025214-2-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: x-y-z

include/trace/events/migrate.h

@@ -49,37 +49,41 @@ TRACE_EVENT(mm_migrate_pages,
 
 	TP_PROTO(unsigned long succeeded, unsigned long failed,
 		 unsigned long thp_succeeded, unsigned long thp_failed,
-		 unsigned long thp_split, enum migrate_mode mode, int reason),
+		 unsigned long thp_split, unsigned long large_folio_split,
+		 enum migrate_mode mode, int reason),
 
 	TP_ARGS(succeeded, failed, thp_succeeded, thp_failed,
-		thp_split, mode, reason),
+		thp_split, large_folio_split, mode, reason),
 
 	TP_STRUCT__entry(
 		__field(	unsigned long,		succeeded)
 		__field(	unsigned long,		failed)
 		__field(	unsigned long,		thp_succeeded)
 		__field(	unsigned long,		thp_failed)
 		__field(	unsigned long,		thp_split)
+		__field(	unsigned long,		large_folio_split)
 		__field(	enum migrate_mode,	mode)
 		__field(	int,			reason)
 	),
 
 	TP_fast_assign(
-		__entry->succeeded	= succeeded;
-		__entry->failed		= failed;
-		__entry->thp_succeeded	= thp_succeeded;
-		__entry->thp_failed	= thp_failed;
-		__entry->thp_split	= thp_split;
-		__entry->mode		= mode;
-		__entry->reason		= reason;
+		__entry->succeeded			= succeeded;
+		__entry->failed				= failed;
+		__entry->thp_succeeded		= thp_succeeded;
+		__entry->thp_failed			= thp_failed;
+		__entry->thp_split			= thp_split;
+		__entry->large_folio_split	= large_folio_split;
+		__entry->mode				= mode;
+		__entry->reason				= reason;
 	),
 
-	TP_printk("nr_succeeded=%lu nr_failed=%lu nr_thp_succeeded=%lu nr_thp_failed=%lu nr_thp_split=%lu mode=%s reason=%s",
+	TP_printk("nr_succeeded=%lu nr_failed=%lu nr_thp_succeeded=%lu nr_thp_failed=%lu nr_thp_split=%lu nr_split=%lu mode=%s reason=%s",
 		__entry->succeeded,
 		__entry->failed,
 		__entry->thp_succeeded,
 		__entry->thp_failed,
 		__entry->thp_split,
+		__entry->large_folio_split,
 		__print_symbolic(__entry->mode, MIGRATE_MODE),
 		__print_symbolic(__entry->reason, MIGRATE_REASON))
 );

mm/migrate.c

@@ -1686,7 +1686,7 @@ static int migrate_pages_batch(struct list_head *from,
 
 					if (!ret) {
 						stats->nr_thp_split += is_thp;
-						stats->nr_split += is_large;
+						stats->nr_split++;
 						break;
 					} else if (reason == MR_LONGTERM_PIN &&
 						   ret == -EAGAIN) {
@@ -1979,7 +1979,8 @@ int migrate_pages(struct list_head *from, new_folio_t get_new_folio,
 	count_vm_events(THP_MIGRATION_SPLIT, stats.nr_thp_split);
 	trace_mm_migrate_pages(stats.nr_succeeded, stats.nr_failed_pages,
 			       stats.nr_thp_succeeded, stats.nr_thp_failed,
-			       stats.nr_thp_split, mode, reason);
+			       stats.nr_thp_split, stats.nr_split, mode,
+			       reason);
 
 	if (ret_succeeded)
 		*ret_succeeded = stats.nr_succeeded;