On Wed, Feb 26, 2025 at 02:06:51AM +0000, Pavel Begunkov wrote: > On 2/26/25 01:53, Darrick J. Wong wrote: > > On Wed, Feb 26, 2025 at 01:33:58AM +0000, Pavel Begunkov wrote: > > > 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; > > > > Shouldn't this go in iomap_dio_bio_opflags? > > It can, if that's the preference, but iomap_dio_zero() would need > to have a separate check. It also affects 5.4, and I'm not sure > which version would be easier to back port. Yes, please don't go scattering the bi_opf setting code all around the file. Also, do you need to modify iomap_dio_zero? --D > -- > Pavel Begunkov >
