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block: add single bio async direct IO helper 

As with __blkdev_direct_IO_simple(), we can implement direct IO more
efficiently if there is only one bio. Add __blkdev_direct_IO_async() and
blkdev_bio_end_io_async(). This patch brings me from 4.45-4.5 MIOPS with
nullblk to 4.7+.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f0ae4109b7a6934adede490f84d188d53b97051b.1635006010.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-10-23 17:21:32 +01:00 committed by Jens Axboe
parent 599593a82f
commit 54a88eb838
1 changed files with 84 additions and 3 deletions
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87
block/fops.c
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@ -305,6 +305,85 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
return ret;
}
static void blkdev_bio_end_io_async(struct bio *bio)
{
struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
struct kiocb *iocb = dio->iocb;
ssize_t ret;
if (likely(!bio->bi_status)) {
ret = dio->size;
iocb->ki_pos += ret;
} else {
ret = blk_status_to_errno(bio->bi_status);
}
iocb->ki_complete(iocb, ret, 0);
if (dio->flags & DIO_SHOULD_DIRTY) {
bio_check_pages_dirty(bio);
} else {
bio_release_pages(bio, false);
bio_put(bio);
}
}
static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
struct iov_iter *iter,
unsigned int nr_pages)
{
struct block_device *bdev = iocb->ki_filp->private_data;
struct blkdev_dio *dio;
struct bio *bio;
loff_t pos = iocb->ki_pos;
int ret = 0;
if ((pos | iov_iter_alignment(iter)) &
(bdev_logical_block_size(bdev) - 1))
return -EINVAL;
bio = bio_alloc_kiocb(iocb, nr_pages, &blkdev_dio_pool);
dio = container_of(bio, struct blkdev_dio, bio);
dio->flags = 0;
dio->iocb = iocb;
bio_set_dev(bio, bdev);
bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
bio->bi_write_hint = iocb->ki_hint;
bio->bi_end_io = blkdev_bio_end_io_async;
bio->bi_ioprio = iocb->ki_ioprio;
ret = bio_iov_iter_get_pages(bio, iter);
if (unlikely(ret)) {
bio->bi_status = BLK_STS_IOERR;
bio_endio(bio);
return ret;
}
dio->size = bio->bi_iter.bi_size;
if (iov_iter_rw(iter) == READ) {
bio->bi_opf = REQ_OP_READ;
if (iter_is_iovec(iter)) {
dio->flags |= DIO_SHOULD_DIRTY;
bio_set_pages_dirty(bio);
}
} else {
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;
if (iocb->ki_flags & IOCB_HIPRI) {
bio_set_polled(bio, iocb);
submit_bio(bio);
WRITE_ONCE(iocb->private, bio);
} else {
submit_bio(bio);
}
return -EIOCBQUEUED;
}
static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
{
unsigned int nr_pages;
@ -313,9 +392,11 @@ static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
return 0;
nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1);
if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_VECS)
return __blkdev_direct_IO_simple(iocb, iter, nr_pages);
if (likely(nr_pages <= BIO_MAX_VECS)) {
if (is_sync_kiocb(iocb))
return __blkdev_direct_IO_simple(iocb, iter, nr_pages);
return __blkdev_direct_IO_async(iocb, iter, nr_pages);
}
return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
}