Commit a31eb4a2 authored by Jiufei Xue's avatar Jiufei Xue Committed by Jens Axboe

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
......@@ -4245,7 +4245,11 @@ static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
pt->error = 0;
poll->head = head;
add_wait_queue(head, &poll->wait);
if (poll->events & EPOLLEXCLUSIVE)
add_wait_queue_exclusive(head, &poll->wait);
else
add_wait_queue(head, &poll->wait);
}
static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
......@@ -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;
......
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