There are reports of high io_uring submission latency for ext4 and xfs, which is due to iomap not propagating nowait flag to the block layer resulting in waiting for IO during tag allocation. Cc: stable@xxxxxxxxxxxxxxx Link: https://github.com/axboe/liburing/issues/826#issuecomment-2674131870 Reported-by: wu lei <uwydoc@xxxxxxxxx> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> --- fs/iomap/direct-io.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index b521eb15759e..25c5e87dbd94 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -81,6 +81,9 @@ static void iomap_dio_submit_bio(const struct iomap_iter *iter, WRITE_ONCE(iocb->private, bio); } + if (iocb->ki_flags & IOCB_NOWAIT) + bio->bi_opf |= REQ_NOWAIT; + if (dio->dops && dio->dops->submit_io) dio->dops->submit_io(iter, bio, pos); else -- 2.48.1
