From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 19 Sep 2019 15:48:55 +0000 (-0600)
Subject: io_uring: use cond_resched() in sqthread
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=9831a90ce64362f8429e8fd23838a9db2cdf7803;p=uclinux-h8%2Flinux.git

io_uring: use cond_resched() in sqthread

If preempt isn't enabled in the kernel, we can run into hang issues with
sqthread submissions. Use cond_resched() to play nice instead of
cpu_relax(), if we end up starting the loop and not having any events
pending for submissions.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 854dedd885fa..05a299e80159 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2438,7 +2438,7 @@ static int io_sq_thread(void *data)
 			 * to sleep.
 			 */
 			if (inflight || !time_after(jiffies, timeout)) {
-				cpu_relax();
+				cond_resched();
 				continue;
 			}