Commit a31eb4a2 authored by Jiufei Xue's avatar Jiufei Xue Committed by Jens Axboe
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io_uring: use EPOLLEXCLUSIVE flag to aoid thundering herd type behavior 



Applications can pass this flag in to avoid accept thundering herd.

Signed-off-by: default avatarJiufei Xue <jiufei.xue@linux.alibaba.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 5769a351

fs/io_uring.c

+7 −2
Original line number Diff line number Diff line
@@ -4245,6 +4245,10 @@ static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt, 


	pt->error = 0;

	poll->head = head;



	if (poll->events & EPOLLEXCLUSIVE)

		add_wait_queue_exclusive(head, &poll->wait);

	else

		add_wait_queue(head, &poll->wait);

}
@@ -4602,7 +4606,8 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe 
#ifdef __BIG_ENDIAN

	events = swahw32(events);

#endif

	poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;

	poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP |

		       (events & EPOLLEXCLUSIVE);



	io_get_req_task(req);

	return 0;