diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 483639fb727b..a411ce2c7501 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -303,10 +303,13 @@ Description:	Do background GC aggressively when set. Set to 0 by default.
 		GC approach and turns SSR mode on.
 		gc urgent low(2): lowers the bar of checking I/O idling in
 		order to process outstanding discard commands and GC a
-		little bit aggressively. uses cost benefit GC approach.
+		little bit aggressively. always uses cost benefit GC approach,
+		and will override age-threshold GC approach if ATGC is enabled
+		at the same time.
 		gc urgent mid(3): does GC forcibly in a period of given
 		gc_urgent_sleep_time and executes a mid level of I/O idling check.
-		uses cost benefit GC approach.
+		always uses cost benefit GC approach, and will override
+		age-threshold GC approach if ATGC is enabled at the same time.
 
 What:		/sys/fs/f2fs/<disk>/gc_urgent_sleep_time
 Date:		August 2017
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 5a661a0e7663..687b2ce82c85 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -227,6 +227,8 @@ static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
 
 	switch (sbi->gc_mode) {
 	case GC_IDLE_CB:
+	case GC_URGENT_LOW:
+	case GC_URGENT_MID:
 		gc_mode = GC_CB;
 		break;
 	case GC_IDLE_GREEDY: