[PATCH v3] f2fs: add async reset zone command support

[Daejun Park]

Changelog:

v2 -> v3
Modified arguments to be correct for ftrace parameter.
Changed __submit_zone_reset_cmd to void return.
Refactored the f2fs_wait_discard_bio function.
Fixed code that was previously incorrectly merged.

v1 -> v2
Changed to apply the optional async reset write pointer by default.

This patch enables submit reset zone command asynchornously. It helps
decrease average latency of write IOs in high utilization scenario by
faster checkpointing.

Signed-off-by: Daejun Park <daejun7.park@xxxxxxxxxxx>
---
 fs/f2fs/segment.c           | 85 ++++++++++++++++++++++++++++++++++---
 include/trace/events/f2fs.h | 18 +++++++-
 2 files changed, 95 insertions(+), 8 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 6db410f1bb8c..d5be88fada0f 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1196,6 +1196,44 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
 static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
 				struct block_device *bdev, block_t lstart,
 				block_t start, block_t len);
+
+#ifdef CONFIG_BLK_DEV_ZONED
+static void __submit_zone_reset_cmd(struct f2fs_sb_info *sbi,
+				   struct discard_cmd *dc, blk_opf_t flag,
+				   struct list_head *wait_list,
+				   unsigned int *issued)
+{
+	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
+	struct block_device *bdev = dc->bdev;
+	struct bio *bio = bio_alloc(bdev, 0, REQ_OP_ZONE_RESET | flag, GFP_NOFS);
+	unsigned long flags;
+
+	trace_f2fs_issue_reset_zone(bdev, dc->di.start);
+
+	spin_lock_irqsave(&dc->lock, flags);
+	dc->state = D_SUBMIT;
+	dc->bio_ref++;
+	spin_unlock_irqrestore(&dc->lock, flags);
+
+	if (issued)
+		(*issued)++;
+
+	atomic_inc(&dcc->queued_discard);
+	dc->queued++;
+	list_move_tail(&dc->list, wait_list);
+
+	/* sanity check on discard range */
+	__check_sit_bitmap(sbi, dc->di.lstart, dc->di.lstart + dc->di.len);
+
+	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(dc->di.start);
+	bio->bi_private = dc;
+	bio->bi_end_io = f2fs_submit_discard_endio;
+	submit_bio(bio);
+
+	atomic_inc(&dcc->issued_discard);
+}
+#endif
+
 /* this function is copied from blkdev_issue_discard from block/blk-lib.c */
 static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
 				struct discard_policy *dpolicy,
@@ -1217,6 +1255,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK))
 		return 0;
 
+#ifdef CONFIG_BLK_DEV_ZONED
+	if (f2fs_sb_has_blkzoned(sbi) && bdev_is_zoned(bdev)) {
+		__submit_zone_reset_cmd(sbi, dc, flag, wait_list, issued);
+		return 0;
+	}
+#endif
+
 	trace_f2fs_issue_discard(bdev, dc->di.start, dc->di.len);
 
 	lstart = dc->di.lstart;
@@ -1461,6 +1506,19 @@ static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
 	}
 }
 
+#ifdef CONFIG_BLK_DEV_ZONED
+static void __queue_zone_reset_cmd(struct f2fs_sb_info *sbi,
+		struct block_device *bdev, block_t blkstart, block_t lblkstart,
+		block_t blklen)
+{
+	trace_f2fs_queue_reset_zone(bdev, blkstart);
+
+	mutex_lock(&SM_I(sbi)->dcc_info->cmd_lock);
+	__insert_discard_cmd(sbi, bdev, lblkstart, blkstart, blklen);
+	mutex_unlock(&SM_I(sbi)->dcc_info->cmd_lock);
+}
+#endif
+
 static void __queue_discard_cmd(struct f2fs_sb_info *sbi,
 		struct block_device *bdev, block_t blkstart, block_t blklen)
 {
@@ -1725,11 +1783,20 @@ static void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, block_t blkaddr)
 	mutex_lock(&dcc->cmd_lock);
 	dc = __lookup_discard_cmd(sbi, blkaddr);
 	if (dc) {
-		if (dc->state == D_PREP) {
-			__punch_discard_cmd(sbi, dc, blkaddr);
-		} else {
+		if (f2fs_sb_has_blkzoned(sbi) && bdev_is_zoned(dc->bdev)) {
+			/* force submit zone reset */
+			if (dc->state == D_PREP)
+				__submit_zone_reset_cmd(sbi, dc, REQ_SYNC,
+							&dcc->wait_list, NULL);
 			dc->ref++;
 			need_wait = true;
+		} else {
+			if (dc->state == D_PREP) {
+				__punch_discard_cmd(sbi, dc, blkaddr);
+			} else {
+				dc->ref++;
+				need_wait = true;
+			}
 		}
 	}
 	mutex_unlock(&dcc->cmd_lock);
@@ -1876,9 +1943,15 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
 				 blkstart, blklen);
 			return -EIO;
 		}
-		trace_f2fs_issue_reset_zone(bdev, blkstart);
-		return blkdev_zone_mgmt(bdev, REQ_OP_ZONE_RESET,
-					sector, nr_sects, GFP_NOFS);
+
+		if (unlikely(!is_sbi_flag_set(sbi, SBI_POR_DOING))) {
+			trace_f2fs_issue_reset_zone(bdev, blkstart);
+			return blkdev_zone_mgmt(bdev, REQ_OP_ZONE_RESET,
+						sector, nr_sects, GFP_NOFS);
+		}
+
+		__queue_zone_reset_cmd(sbi, bdev, blkstart, lblkstart, blklen);
+		return 0;
 	}
 
 	/* For conventional zones, use regular discard if supported */
diff --git a/include/trace/events/f2fs.h b/include/trace/events/f2fs.h
index 99cbc5949e3c..ee1477de8324 100644
--- a/include/trace/events/f2fs.h
+++ b/include/trace/events/f2fs.h
@@ -1512,7 +1512,7 @@ DEFINE_EVENT(f2fs_discard, f2fs_remove_discard,
 	TP_ARGS(dev, blkstart, blklen)
 );
 
-TRACE_EVENT(f2fs_issue_reset_zone,
+DECLARE_EVENT_CLASS(f2fs_reset_zone,
 
 	TP_PROTO(struct block_device *dev, block_t blkstart),
 
@@ -1528,11 +1528,25 @@ TRACE_EVENT(f2fs_issue_reset_zone,
 		__entry->blkstart = blkstart;
 	),
 
-	TP_printk("dev = (%d,%d), reset zone at block = 0x%llx",
+	TP_printk("dev = (%d,%d), zone at block = 0x%llx",
 		show_dev(__entry->dev),
 		(unsigned long long)__entry->blkstart)
 );
 
+DEFINE_EVENT(f2fs_reset_zone, f2fs_queue_reset_zone,
+
+	TP_PROTO(struct block_device *dev, block_t blkstart),
+
+	TP_ARGS(dev, blkstart)
+);
+
+DEFINE_EVENT(f2fs_reset_zone, f2fs_issue_reset_zone,
+
+	TP_PROTO(struct block_device *dev, block_t blkstart),
+
+	TP_ARGS(dev, blkstart)
+);
+
 TRACE_EVENT(f2fs_issue_flush,
 
 	TP_PROTO(struct block_device *dev, unsigned int nobarrier,
-- 
2.25.1