[PATCH 1/2] f2fs: delay awaking discard thread

[Chao Yu]

From: Chao Yu <yuchao0@xxxxxxxxxx>

It's better to delay awaking discard thread while queuing discard commands
in checkpoint, it will help to give more chances for merging big and small
discard.

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
 fs/f2fs/segment.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d4bda1e54475..8097b4c8c7c7 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -971,7 +971,6 @@ static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
 		blkstart -= FDEV(devi).start_blk;
 	}
 	__update_discard_tree_range(sbi, bdev, lblkstart, blkstart, blklen);
-	wake_up(&SM_I(sbi)->dcc_info->discard_wait_queue);
 	return 0;
 }
 
@@ -1338,6 +1337,8 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
 		SM_I(sbi)->dcc_info->nr_discards -= total_len;
 		kmem_cache_free(discard_entry_slab, entry);
 	}
+
+	wake_up(&SM_I(sbi)->dcc_info->discard_wait_queue);
 }
 
 static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
-- 
2.12.2.575.gb14f27f