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io_uring: don't sleep when polling for I/O

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There is no point in sleeping for the expected I/O completion timeout
in the io_uring async polling model as we never poll for a specific
I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2021-10-12 13:12:20 +02:00 committed by Jens Axboe
parent ef99b2d376
commit d729cf9acb
3 changed files with 5 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
block/blk-mq.c
View file

@ -4103,7 +4103,8 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags)
if (current->plug) if (current->plug)
blk_flush_plug_list(current->plug, false); blk_flush_plug_list(current->plug, false);
if (q->poll_nsec != BLK_MQ_POLL_CLASSIC) { if (!(flags & BLK_POLL_NOSLEEP) &&
q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
if (blk_mq_poll_hybrid(q, cookie)) if (blk_mq_poll_hybrid(q, cookie))
return 1; return 1;
} }

2
fs/io_uring.c
View file

@ -2457,7 +2457,7 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
long min) long min)
{ {
struct io_kiocb *req, *tmp; struct io_kiocb *req, *tmp;
unsigned int poll_flags = 0; unsigned int poll_flags = BLK_POLL_NOSLEEP;
LIST_HEAD(done); LIST_HEAD(done);
/* /*

2
include/linux/blkdev.h
View file

@ -566,6 +566,8 @@ blk_status_t errno_to_blk_status(int errno);
/* only poll the hardware once, don't continue until a completion was found */ /* only poll the hardware once, don't continue until a completion was found */
#define BLK_POLL_ONESHOT (1 << 0) #define BLK_POLL_ONESHOT (1 << 0)
/* do not sleep to wait for the expected completion time */
#define BLK_POLL_NOSLEEP (1 << 1)
int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags); int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags);
static inline struct request_queue *bdev_get_queue(struct block_device *bdev) static inline struct request_queue *bdev_get_queue(struct block_device *bdev)