Re: [PATCH] block: don't ignore REQ_NOWAIT for direct IO
From: Pavel Begunkov <asml.silence@gmail.com>
Date: 2020-11-20 17:16:31
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On 20/11/2020 17:10, 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.
I'll leave it for judgement to those who know that code better, but io_schedule() is gone from my traces.
quoted hunk ↗ jump to hunk
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- 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);@@ -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;
-- Pavel Begunkov