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>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index bfbf64f..c556775 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1092,6 +1092,8 @@
 enum {
 	CP_TIME,
 	REQ_TIME,
+	DISCARD_TIME,
+	GC_TIME,
 	MAX_TIME,
 };
 
@@ -1343,7 +1345,15 @@
 
 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)
@@ -1353,7 +1363,21 @@
 	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);
@@ -1362,7 +1386,7 @@
 	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);
 }
 
 /*