While we submit direct writes, if the inode is flagged with nodatasum, there's no benefit to submit asynchronously, because a) we don't have to calculate checksum across processors, b) and direct IO has started a plug, but async submit makes us queue IO on each device's scheduled IO list instead of DIO's plug list, so that IOs get much less merges in general. Lets use sync submit for nodatasum inodes. Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx> --- fs/btrfs/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 95c2120..f4a48d8 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8467,7 +8467,7 @@ static inline int __btrfs_submit_dio_bio(struct bio *bio, struct inode *inode, goto err; } map: - ret = btrfs_map_bio(fs_info, bio, 0, async_submit); + ret = btrfs_map_bio(fs_info, bio, 0, 0); err: bio_put(bio); return ret; -- 2.9.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
