f2fs: add new idle interval timing for discard and gc paths

This helps to control the frequency of submission of discard and
GC requests independently, based on the need.
Suggested-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Documentation/ABI/testing/sysfs-fs-f2fs

@@ -121,7 +121,22 @@ What:		/sys/fs/f2fs/<disk>/idle_interval
 Date:		January 2016
 Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>
 Description:
-		 Controls the idle timing.
+		 Controls the idle timing for all paths other than
+		 discard and gc path.
+
+What:		/sys/fs/f2fs/<disk>/discard_idle_interval
+Date:		September 2018
+Contact:	"Chao Yu" <yuchao0@huawei.com>
+Contact:	"Sahitya Tummala" <stummala@codeaurora.org>
+Description:
+		 Controls the idle timing for discard path.
+
+What:		/sys/fs/f2fs/<disk>/gc_idle_interval
+Date:		September 2018
+Contact:	"Chao Yu" <yuchao0@huawei.com>
+Contact:	"Sahitya Tummala" <stummala@codeaurora.org>
+Description:
+		 Controls the idle timing for gc path.
 
 What:		/sys/fs/f2fs/<disk>/iostat_enable
 Date:		August 2017

fs/f2fs/f2fs.h

@@ -1093,6 +1093,8 @@ enum {
 enum {
 	CP_TIME,
 	REQ_TIME,
+	DISCARD_TIME,
+	GC_TIME,
 	MAX_TIME,
 };
 
@@ -1344,7 +1346,15 @@ static inline bool time_to_inject(struct f2fs_sb_info *sbi, int type)
 
 static inline void f2fs_update_time(struct f2fs_sb_info *sbi, int type)
 {
-	sbi->last_time[type] = jiffies;
+	unsigned long now = jiffies;
+
+	sbi->last_time[type] = now;
+
+	/* DISCARD_TIME and GC_TIME are based on REQ_TIME */
+	if (type == REQ_TIME) {
+		sbi->last_time[DISCARD_TIME] = now;
+		sbi->last_time[GC_TIME] = now;
+	}
 }
 
 static inline bool f2fs_time_over(struct f2fs_sb_info *sbi, int type)
@@ -1354,7 +1364,21 @@ static inline bool f2fs_time_over(struct f2fs_sb_info *sbi, int type)
 	return time_after(jiffies, sbi->last_time[type] + interval);
 }
 
-static inline bool is_idle(struct f2fs_sb_info *sbi)
+static inline unsigned int f2fs_time_to_wait(struct f2fs_sb_info *sbi,
+						int type)
+{
+	unsigned long interval = sbi->interval_time[type] * HZ;
+	unsigned int wait_ms = 0;
+	long delta;
+
+	delta = (sbi->last_time[type] + interval) - jiffies;
+	if (delta > 0)
+		wait_ms = jiffies_to_msecs(delta);
+
+	return wait_ms;
+}
+
+static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
 {
 	struct block_device *bdev = sbi->sb->s_bdev;
 	struct request_queue *q = bdev_get_queue(bdev);
@@ -1363,7 +1387,7 @@ static inline bool is_idle(struct f2fs_sb_info *sbi)
 	if (rl->count[BLK_RW_SYNC] || rl->count[BLK_RW_ASYNC])
 		return false;
 
-	return f2fs_time_over(sbi, REQ_TIME);
+	return f2fs_time_over(sbi, type);
 }
 
 /*

fs/f2fs/gc.c

@@ -80,7 +80,7 @@ static int gc_thread_func(void *data)
 		if (!mutex_trylock(&sbi->gc_mutex))
 			goto next;
 
-		if (!is_idle(sbi)) {
+		if (!is_idle(sbi, GC_TIME)) {
 			increase_sleep_time(gc_th, &wait_ms);
 			mutex_unlock(&sbi->gc_mutex);
 			goto next;

fs/f2fs/segment.c

@@ -508,7 +508,7 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
 	else
 		f2fs_build_free_nids(sbi, false, false);
 
-	if (!is_idle(sbi) &&
+	if (!is_idle(sbi, REQ_TIME) &&
 		(!excess_dirty_nats(sbi) && !excess_dirty_nodes(sbi)))
 		return;
 
@@ -1308,7 +1308,7 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
 		if (dc->state != D_PREP)
 			goto next;
 
-		if (dpolicy->io_aware && !is_idle(sbi)) {
+		if (dpolicy->io_aware && !is_idle(sbi, DISCARD_TIME)) {
 			io_interrupted = true;
 			break;
 		}
@@ -1368,7 +1368,7 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
 			f2fs_bug_on(sbi, dc->state != D_PREP);
 
 			if (dpolicy->io_aware && i < dpolicy->io_aware_gran &&
-								!is_idle(sbi)) {
+						!is_idle(sbi, DISCARD_TIME)) {
 				io_interrupted = true;
 				break;
 			}
@@ -1561,8 +1561,6 @@ static int issue_discard_thread(void *data)
 	struct discard_policy dpolicy;
 	unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
 	int issued;
-	unsigned long interval = sbi->interval_time[REQ_TIME] * HZ;
-	long delta;
 
 	set_freezable();
 
@@ -1599,10 +1597,8 @@ static int issue_discard_thread(void *data)
 			__wait_all_discard_cmd(sbi, &dpolicy);
 			wait_ms = dpolicy.min_interval;
 		} else if (issued == -1){
-			delta = (sbi->last_time[REQ_TIME] + interval) - jiffies;
-			if (delta > 0)
-				wait_ms = jiffies_to_msecs(delta);
-			else
+			wait_ms = f2fs_time_to_wait(sbi, DISCARD_TIME);
+			if (!wait_ms)
 				wait_ms = dpolicy.mid_interval;
 		} else {
 			wait_ms = dpolicy.max_interval;

fs/f2fs/super.c

@@ -2461,6 +2461,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
 	sbi->dir_level = DEF_DIR_LEVEL;
 	sbi->interval_time[CP_TIME] = DEF_CP_INTERVAL;
 	sbi->interval_time[REQ_TIME] = DEF_IDLE_INTERVAL;
+	sbi->interval_time[DISCARD_TIME] = DEF_IDLE_INTERVAL;
+	sbi->interval_time[GC_TIME] = DEF_IDLE_INTERVAL;
 	clear_sbi_flag(sbi, SBI_NEED_FSCK);
 
 	for (i = 0; i < NR_COUNT_TYPE; i++)

fs/f2fs/sysfs.c

@@ -404,6 +404,9 @@ F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_victim_search, max_victim_search);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, dir_level, dir_level);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, cp_interval, interval_time[CP_TIME]);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, idle_interval, interval_time[REQ_TIME]);
+F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, discard_idle_interval,
+					interval_time[DISCARD_TIME]);
+F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_idle_interval, interval_time[GC_TIME]);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, iostat_enable, iostat_enable);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, readdir_ra, readdir_ra);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_pin_file_thresh, gc_pin_file_threshold);
@@ -457,6 +460,8 @@ static struct attribute *f2fs_attrs[] = {
 	ATTR_LIST(dirty_nats_ratio),
 	ATTR_LIST(cp_interval),
 	ATTR_LIST(idle_interval),
+	ATTR_LIST(discard_idle_interval),
+	ATTR_LIST(gc_idle_interval),
 	ATTR_LIST(iostat_enable),
 	ATTR_LIST(readdir_ra),
 	ATTR_LIST(gc_pin_file_thresh),