[PATCH v2 1/7] f2fs: make BG GC more aggressive for zoned devices

[Daeho Jeong]

From: Daeho Jeong <daehojeong@xxxxxxxxxx>

Since we don't have any GC on device side for zoned devices, need more
aggressive BG GC. So, tune the parameters for that.

Signed-off-by: Daeho Jeong <daehojeong@xxxxxxxxxx>
---
 fs/f2fs/f2fs.h  | 20 ++++++++++++++++++--
 fs/f2fs/gc.c    | 25 +++++++++++++++++++++----
 fs/f2fs/gc.h    | 21 +++++++++++++++++++++
 fs/f2fs/super.c |  5 +++++
 4 files changed, 65 insertions(+), 6 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ac19c61f0c3e..5e4db3ba534a 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2854,13 +2854,26 @@ static inline bool is_inflight_io(struct f2fs_sb_info *sbi, int type)
 	return false;
 }
 
+static inline bool is_inflight_read_io(struct f2fs_sb_info *sbi)
+{
+	return get_pages(sbi, F2FS_RD_DATA) || get_pages(sbi, F2FS_DIO_READ);
+}
+
 static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
 {
+	bool zoned_gc = (type == GC_TIME &&
+			F2FS_HAS_FEATURE(sbi, F2FS_FEATURE_BLKZONED));
+
 	if (sbi->gc_mode == GC_URGENT_HIGH)
 		return true;
 
-	if (is_inflight_io(sbi, type))
-		return false;
+	if (zoned_gc) {
+		if (is_inflight_read_io(sbi))
+			return false;
+	} else {
+		if (is_inflight_io(sbi, type))
+			return false;
+	}
 
 	if (sbi->gc_mode == GC_URGENT_MID)
 		return true;
@@ -2869,6 +2882,9 @@ static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
 			(type == DISCARD_TIME || type == GC_TIME))
 		return true;
 
+	if (zoned_gc)
+		return true;
+
 	return f2fs_time_over(sbi, type);
 }
 
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 724bbcb447d3..46e3bc26b78a 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -116,7 +116,17 @@ static int gc_thread_func(void *data)
 			goto next;
 		}
 
-		if (has_enough_invalid_blocks(sbi))
+		if (f2fs_sb_has_blkzoned(sbi)) {
+			if (has_enough_free_blocks(sbi, LIMIT_NO_ZONED_GC)) {
+				wait_ms = gc_th->no_gc_sleep_time;
+				f2fs_up_write(&sbi->gc_lock);
+				goto next;
+			}
+			if (wait_ms == gc_th->no_gc_sleep_time)
+				wait_ms = gc_th->max_sleep_time;
+		}
+
+		if (need_to_boost_gc(sbi))
 			decrease_sleep_time(gc_th, &wait_ms);
 		else
 			increase_sleep_time(gc_th, &wait_ms);
@@ -179,9 +189,16 @@ int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
 		return -ENOMEM;
 
 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
-	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
-	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
-	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
+
+	if (f2fs_sb_has_blkzoned(sbi)) {
+		gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME_ZONED;
+		gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME_ZONED;
+		gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME_ZONED;
+	} else {
+		gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
+		gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
+		gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
+	}
 
 	gc_th->gc_wake = false;
 
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index a8ea3301b815..55c4ba73362e 100644
--- a/fs/f2fs/gc.h
+++ b/fs/f2fs/gc.h
@@ -15,6 +15,11 @@
 #define DEF_GC_THREAD_MAX_SLEEP_TIME	60000
 #define DEF_GC_THREAD_NOGC_SLEEP_TIME	300000	/* wait 5 min */
 
+/* GC sleep parameters for zoned deivces */
+#define DEF_GC_THREAD_MIN_SLEEP_TIME_ZONED	10
+#define DEF_GC_THREAD_MAX_SLEEP_TIME_ZONED	20
+#define DEF_GC_THREAD_NOGC_SLEEP_TIME_ZONED	60000
+
 /* choose candidates from sections which has age of more than 7 days */
 #define DEF_GC_THREAD_AGE_THRESHOLD		(60 * 60 * 24 * 7)
 #define DEF_GC_THREAD_CANDIDATE_RATIO		20	/* select 20% oldest sections as candidates */
@@ -25,6 +30,9 @@
 #define LIMIT_INVALID_BLOCK	40 /* percentage over total user space */
 #define LIMIT_FREE_BLOCK	40 /* percentage over invalid + free space */
 
+#define LIMIT_NO_ZONED_GC	60 /* percentage over total user space of no gc for zoned devices */
+#define LIMIT_BOOST_ZONED_GC	25 /* percentage over total user space of boosted gc for zoned devices */
+
 #define DEF_GC_FAILED_PINNED_FILES	2048
 #define MAX_GC_FAILED_PINNED_FILES	USHRT_MAX
 
@@ -152,6 +160,12 @@ static inline void decrease_sleep_time(struct f2fs_gc_kthread *gc_th,
 		*wait -= min_time;
 }
 
+static inline bool has_enough_free_blocks(struct f2fs_sb_info *sbi,
+						unsigned int limit_perc)
+{
+	return free_sections(sbi) > ((sbi->total_sections * limit_perc) / 100);
+}
+
 static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
 {
 	block_t user_block_count = sbi->user_block_count;
@@ -167,3 +181,10 @@ static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
 		free_user_blocks(sbi) <
 			limit_free_user_blocks(invalid_user_blocks));
 }
+
+static inline bool need_to_boost_gc(struct f2fs_sb_info *sbi)
+{
+	if (f2fs_sb_has_blkzoned(sbi))
+		return !has_enough_free_blocks(sbi, LIMIT_BOOST_ZONED_GC);
+	return has_enough_invalid_blocks(sbi);
+}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 3959fd137cc9..ca2101ad918e 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -707,6 +707,11 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
 			if (!strcmp(name, "on")) {
 				F2FS_OPTION(sbi).bggc_mode = BGGC_MODE_ON;
 			} else if (!strcmp(name, "off")) {
+				if (f2fs_sb_has_blkzoned(sbi)) {
+					f2fs_warn(sbi, "zoned devices need bggc");
+					kfree(name);
+					return -EINVAL;
+				}
 				F2FS_OPTION(sbi).bggc_mode = BGGC_MODE_OFF;
 			} else if (!strcmp(name, "sync")) {
 				F2FS_OPTION(sbi).bggc_mode = BGGC_MODE_SYNC;
-- 
2.46.0.598.g6f2099f65c-goog