From: Pavel Begunkov <asml.silence@gmail.com>
To: linux-block@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>, Pavel Begunkov <asml.silence@gmail.com>
Subject: [PATCH 09/16] block: optimise boundary blkdev_read_iter's checks
Date: Tue, 19 Oct 2021 22:24:18 +0100 [thread overview]
Message-ID: <d8660b783e2237063a00f671afcf17a30c2e2c76.1634676157.git.asml.silence@gmail.com> (raw)
In-Reply-To: <cover.1634676157.git.asml.silence@gmail.com>
Combine pos and len checks and mark unlikely. Also, don't reexpand if
it's not truncated.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
block/fops.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/block/fops.c b/block/fops.c
index 21d25ee0e4bf..8f733c919ed1 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -503,17 +503,20 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
size_t shorted = 0;
ssize_t ret;
- if (pos >= size)
- return 0;
-
- size -= pos;
- if (iov_iter_count(to) > size) {
- shorted = iov_iter_count(to) - size;
- iov_iter_truncate(to, size);
+ if (unlikely(pos + iov_iter_count(to) > size)) {
+ if (pos >= size)
+ return 0;
+ size -= pos;
+ if (iov_iter_count(to) > size) {
+ shorted = iov_iter_count(to) - size;
+ iov_iter_truncate(to, size);
+ }
}
ret = generic_file_read_iter(iocb, to);
- iov_iter_reexpand(to, iov_iter_count(to) + shorted);
+
+ if (unlikely(shorted))
+ iov_iter_reexpand(to, iov_iter_count(to) + shorted);
return ret;
}
--
2.33.1
next prev parent reply other threads:[~2021-10-19 21:24 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-19 21:24 [PATCH 00/16] block optimisation round Pavel Begunkov
2021-10-19 21:24 ` [PATCH 01/16] block: turn macro helpers into inline functions Pavel Begunkov
2021-10-20 6:09 ` Christoph Hellwig
2021-10-19 21:24 ` [PATCH 02/16] block: convert leftovers to bdev_get_queue Pavel Begunkov
2021-10-19 22:34 ` Chaitanya Kulkarni
2021-10-19 21:24 ` [PATCH 03/16] block: optimise req_bio_endio() Pavel Begunkov
2021-10-20 6:11 ` Christoph Hellwig
2021-10-22 9:58 ` Shinichiro Kawasaki
2021-10-22 10:58 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 04/16] block: don't bloat enter_queue with percpu_ref Pavel Begunkov
2021-10-19 22:32 ` Chaitanya Kulkarni
2021-10-20 6:12 ` Christoph Hellwig
2021-10-20 12:08 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 05/16] block: inline a part of bio_release_pages() Pavel Begunkov
2021-10-20 6:13 ` Christoph Hellwig
2021-10-20 12:19 ` Pavel Begunkov
2021-10-20 14:15 ` Jens Axboe
2021-10-20 17:29 ` Christoph Hellwig
2021-10-19 21:24 ` [PATCH 06/16] block: clean up blk_mq_submit_bio() merging Pavel Begunkov
2021-10-20 6:16 ` Christoph Hellwig
2021-10-20 12:20 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 07/16] blocK: move plug flush functions to blk-mq.c Pavel Begunkov
2021-10-19 22:34 ` Chaitanya Kulkarni
2021-10-20 6:17 ` Christoph Hellwig
2021-10-20 12:23 ` Pavel Begunkov
2021-10-20 12:37 ` Christoph Hellwig
2021-10-20 13:18 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 08/16] block: optimise blk_flush_plug_list Pavel Begunkov
2021-10-20 6:29 ` Christoph Hellwig
2021-10-20 12:26 ` Pavel Begunkov
2021-10-19 21:24 ` Pavel Begunkov [this message]
2021-10-20 6:29 ` [PATCH 09/16] block: optimise boundary blkdev_read_iter's checks Christoph Hellwig
2021-10-19 21:24 ` [PATCH 10/16] block: optimise blkdev_bio_end_io() Pavel Begunkov
2021-10-20 6:30 ` Christoph Hellwig
2021-10-20 12:29 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 11/16] block: add optimised version bio_set_dev() Pavel Begunkov
2021-10-19 22:36 ` Chaitanya Kulkarni
2021-10-20 6:20 ` Christoph Hellwig
2021-10-20 12:29 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 12/16] block: add single bio async direct IO helper Pavel Begunkov
2021-10-20 6:36 ` Christoph Hellwig
2021-10-20 12:35 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 13/16] block: add async version of bio_set_polled Pavel Begunkov
2021-10-20 6:37 ` Christoph Hellwig
2021-10-20 12:58 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 14/16] block: skip advance when async and not needed Pavel Begunkov
2021-10-20 6:41 ` Christoph Hellwig
2021-10-19 21:24 ` [PATCH 15/16] block: optimise blk_may_split for normal rw Pavel Begunkov
2021-10-20 6:25 ` Christoph Hellwig
2021-10-20 13:38 ` Pavel Begunkov
2021-10-19 21:24 ` [PATCH 16/16] block: optimise submit_bio_checks " Pavel Begunkov
2021-10-20 6:26 ` Christoph Hellwig
2021-10-19 23:31 ` [PATCH 00/16] block optimisation round Jens Axboe
2021-10-20 0:21 ` Jens Axboe
2021-10-20 0:22 ` Jens Axboe
2021-10-20 14:12 ` (subset) " Jens Axboe
2021-10-20 14:54 ` Pavel Begunkov
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