Commit 16f72070 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: don't resched with empty task_list 



Entering tctx_task_work() with empty task_list is a strange scenario,
that can happen only on rare occasion during task exit, so let's not
check for task_list emptiness in advance and do it do-while style. The
code still correct for the empty case, just would do extra work about
which we don't care.

Do extra step and do the check before cond_resched(), so we don't
resched if have nothing to execute.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c4173e288e69793d03c7d7ce826f9d28afba718a.1623949695.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c6538be9

fs/io_uring.c

+3 −1
Original line number Diff line number Diff line
@@ -1896,7 +1896,7 @@ static void tctx_task_work(struct callback_head *cb) 


	clear_bit(0, &tctx->task_state);



	while (!wq_list_empty(&tctx->task_list)) {

	while (1) {

		struct io_wq_work_node *node;



		spin_lock_irq(&tctx->task_lock);
@@ -1917,6 +1917,8 @@ static void tctx_task_work(struct callback_head *cb) 
			req->task_work.func(&req->task_work);

			node = next;

		}

		if (wq_list_empty(&tctx->task_list))

			break;

		cond_resched();

	}