From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>,
Ming Lei <ming.lei@redhat.com>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
"Wunderlich, Mark" <mark.wunderlich@intel.com>,
"Vasudevan, Anil" <anil.vasudevan@intel.com>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-nvme@lists.infradead.org
Subject: [PATCH 02/15] block: don't try to poll multi-bio I/Os in __blkdev_direct_IO
Date: Wed, 12 May 2021 15:15:32 +0200 [thread overview]
Message-ID: <20210512131545.495160-3-hch@lst.de> (raw)
In-Reply-To: <20210512131545.495160-1-hch@lst.de>
If an iocb is split into multiple bios we can't poll for both. So don't
bother to even try to poll in that case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/block_dev.c | 37 ++++++++++++++-----------------------
1 file changed, 14 insertions(+), 23 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b8abccd03e5d..0080a3b710b4 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -375,7 +375,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
struct blk_plug plug;
struct blkdev_dio *dio;
struct bio *bio;
- bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
+ bool is_poll = (iocb->ki_flags & IOCB_HIPRI), do_poll = false;
bool is_read = (iov_iter_rw(iter) == READ), is_sync;
loff_t pos = iocb->ki_pos;
blk_qc_t qc = BLK_QC_T_NONE;
@@ -437,22 +437,9 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
pos += bio->bi_iter.bi_size;
nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
- if (!nr_pages) {
- bool polled = false;
-
- if (iocb->ki_flags & IOCB_HIPRI) {
- bio_set_polled(bio, iocb);
- polled = true;
- }
-
- qc = submit_bio(bio);
-
- if (polled)
- WRITE_ONCE(iocb->ki_cookie, qc);
- break;
- }
-
- if (!dio->multi_bio) {
+ if (dio->multi_bio) {
+ atomic_inc(&dio->ref);
+ } else if (nr_pages) {
/*
* AIO needs an extra reference to ensure the dio
* structure which is embedded into the first bio
@@ -462,11 +449,16 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
bio_get(bio);
dio->multi_bio = true;
atomic_set(&dio->ref, 2);
- } else {
- atomic_inc(&dio->ref);
+ } else if (is_poll) {
+ bio_set_polled(bio, iocb);
+ do_poll = true;
+ }
+ qc = submit_bio(bio);
+ if (!nr_pages) {
+ if (do_poll)
+ WRITE_ONCE(iocb->ki_cookie, qc);
+ break;
}
-
- submit_bio(bio);
bio = bio_alloc(GFP_KERNEL, nr_pages);
}
@@ -481,8 +473,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
if (!READ_ONCE(dio->waiter))
break;
- if (!(iocb->ki_flags & IOCB_HIPRI) ||
- !blk_poll(bdev_get_queue(bdev), qc, true))
+ if (!do_poll || !blk_poll(bdev_get_queue(bdev), qc, true))
blk_io_schedule();
}
__set_current_state(TASK_RUNNING);
--
2.30.2
next prev parent reply other threads:[~2021-05-12 13:16 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 13:15 switch block layer polling to a bio based model v3 Christoph Hellwig
2021-05-12 13:15 ` [PATCH 01/15] direct-io: remove blk_poll support Christoph Hellwig
2021-05-12 13:15 ` Christoph Hellwig [this message]
2021-05-12 20:54 ` [PATCH 02/15] block: don't try to poll multi-bio I/Os in __blkdev_direct_IO Sagi Grimberg
2021-05-16 18:01 ` Kanchan Joshi
2021-05-12 13:15 ` [PATCH 03/15] iomap: don't try to poll multi-bio I/Os in __iomap_dio_rw Christoph Hellwig
2021-05-12 21:32 ` Darrick J. Wong
2021-05-12 13:15 ` [PATCH 04/15] blk-mq: factor out a blk_qc_to_hctx helper Christoph Hellwig
2021-05-12 20:58 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 05/15] blk-mq: factor out a "classic" poll helper Christoph Hellwig
2021-05-12 20:59 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 06/15] blk-mq: remove blk_qc_t_to_tag and blk_qc_t_is_internal Christoph Hellwig
2021-05-12 21:42 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 07/15] blk-mq: remove blk_qc_t_valid Christoph Hellwig
2021-05-12 21:43 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 08/15] io_uring: don't sleep when polling for I/O Christoph Hellwig
2021-05-12 21:55 ` Sagi Grimberg
2021-05-19 13:02 ` Christoph Hellwig
2021-05-12 13:15 ` [PATCH 09/15] block: rename REQ_HIPRI to REQ_POLLED Christoph Hellwig
2021-05-12 21:56 ` Sagi Grimberg
2021-05-12 22:43 ` Chaitanya Kulkarni
2021-05-12 13:15 ` [PATCH 10/15] block: use SLAB_TYPESAFE_BY_RCU for the bio slab Christoph Hellwig
2021-05-12 13:15 ` [PATCH 11/15] block: define 'struct bvec_iter' as packed Christoph Hellwig
2021-05-12 21:58 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 12/15] block: switch polling to be bio based Christoph Hellwig
2021-05-12 22:03 ` Sagi Grimberg
2021-05-12 22:12 ` Keith Busch
2021-05-14 2:50 ` Keith Busch
2021-05-14 16:26 ` Keith Busch
2021-05-14 16:28 ` Christoph Hellwig
2021-05-13 1:26 ` Ming Lei
2021-05-13 1:23 ` Ming Lei
2021-05-12 13:15 ` [PATCH 13/15] block: don't allow writing to the poll queue attribute Christoph Hellwig
2021-05-12 22:04 ` Sagi Grimberg
2021-05-12 13:15 ` [PATCH 14/15] nvme-multipath: set QUEUE_FLAG_NOWAIT Christoph Hellwig
2021-05-12 13:15 ` [PATCH 15/15] nvme-multipath: enable polled I/O Christoph Hellwig
2021-05-12 22:10 ` Sagi Grimberg
2021-05-12 22:16 ` Keith Busch
2021-05-13 23:33 ` switch block layer polling to a bio based model v3 Wunderlich, Mark
-- strict thread matches above, loose matches on Subject: below --
2021-04-27 16:16 switch block layer polling to a bio based model v2 Christoph Hellwig
2021-04-27 16:16 ` [PATCH 02/15] block: don't try to poll multi-bio I/Os in __blkdev_direct_IO Christoph Hellwig
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