From f36ba6cf1ab6b05a538aae9cca896917db14ba27 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 5 Jan 2023 11:22:21 +0000 Subject: [PATCH] io_uring: don't iterate cq wait fast path Task work runners keep running until all queues tw items are exhausted. It's also rare for defer tw to queue normal tw and vise versa. Taking it into account, there is only a dim chance that further iterating the io_cqring_wait() fast path will get us anything and so we can remove the loop there. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/1f9565726661266abaa5d921e97433c831759ecf.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index da9b0397f9a1..dfc94654e082 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2510,18 +2510,16 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, if (!io_allowed_run_tw(ctx)) return -EEXIST; - - do { - /* always run at least 1 task work to process local work */ - ret = io_run_task_work_ctx(ctx); + if (!llist_empty(&ctx->work_llist)) { + ret = io_run_local_work(ctx); if (ret < 0) return ret; - io_cqring_overflow_flush(ctx); - - /* if user messes with these they will just get an early return */ - if (__io_cqring_events_user(ctx) >= min_events) - return 0; - } while (ret > 0); + } + io_run_task_work(); + io_cqring_overflow_flush(ctx); + /* if user messes with these they will just get an early return */ + if (__io_cqring_events_user(ctx) >= min_events) + return 0; if (sig) { #ifdef CONFIG_COMPAT -- 2.25.1