io-wq: add cond_resched() to worker thread

to #26323578

commit fd1c4bc6e9b34a5e4fe7a3130a49380ef9d7037c upstream.

Reschedule the current IO worker to cut the risk that it is becoming
a cpu hog.
Signed-off-by: NHillf Danton <hdanton@sina.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

fs/io-wq.c

@@ -430,6 +430,8 @@ static void io_worker_handle_work(struct io_worker *worker)
 		if (signal_pending(current))
 			flush_signals(current);
 
+		cond_resched();
+
 		spin_lock_irq(&worker->lock);
 		worker->cur_work = work;
 		spin_unlock_irq(&worker->lock);