On 11/20/20 10:10 AM, Pavel Begunkov wrote: > io_uring's direct nowait requests end up waiting on io_schedule() in > sbitmap, that's seems to be so because blkdev_direct_IO() fails to > propagate IOCB_NOWAIT to a bio and hence to blk-mq. > > Signed-off-by: Pavel Begunkov <[email protected]> > --- > fs/block_dev.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/fs/block_dev.c b/fs/block_dev.c > index 9e84b1928b94..e7e860c78d93 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -263,6 +263,8 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct > iov_iter *iter, > bio.bi_opf = dio_bio_write_op(iocb); > task_io_account_write(ret); > } > + if (iocb->ki_flags & IOCB_NOWAIT) > + bio.bi_opf |= REQ_NOWAIT; > if (iocb->ki_flags & IOCB_HIPRI) > bio_set_polled(&bio, iocb);
Was thinking this wasn't needed, but I guess that users could do sync && NOWAIT and get -EAGAIN if using preadv2/pwritev2. > @@ -416,6 +418,8 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter > *iter, int nr_pages) > bio->bi_opf = dio_bio_write_op(iocb); > task_io_account_write(bio->bi_iter.bi_size); > } > + if (iocb->ki_flags & IOCB_NOWAIT) > + bio->bi_opf |= REQ_NOWAIT; > > dio->size += bio->bi_iter.bi_size; > pos += bio->bi_iter.bi_size; Looks fine to me, we definitely should not be waiting on tags for IOCB_NOWAIT IO. Will run some shakedown and test for 5.11. -- Jens Axboe
