From 16f72070386fca59312bde696cff917bb04b183e Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 17 Jun 2021 18:14:09 +0100 Subject: [PATCH] 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: Pavel Begunkov Link: https://lore.kernel.org/r/c4173e288e69793d03c7d7ce826f9d28afba718a.1623949695.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 51db0d80b67b..55bc348ed8fe 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -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(); } -- 2.11.0