From: Marco Crivellari Date: Fri, 5 Sep 2025 09:02:40 +0000 (+0200) Subject: io_uring: replace use of system_unbound_wq with system_dfl_wq X-Git-Tag: v6.18-rc1~137^2~26 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9f5f69d98efbcd4edb1c191cf91418688145e0d5;p=thirdparty%2Flinux.git io_uring: replace use of system_unbound_wq with system_dfl_wq Currently if a user enqueue a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This lack of consistentcy cannot be addressed without refactoring the API. system_unbound_wq should be the default workqueue so as not to enforce locality constraints for random work whenever it's not required. Adding system_dfl_wq to encourage its use when unbound work should be used. queue_work() / queue_delayed_work() / mod_delayed_work() will now use the new unbound wq: whether the user still use the old wq a warn will be printed along with a wq redirect to the new one. The old system_unbound_wq will be kept for a few release cycles. Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Signed-off-by: Jens Axboe --- diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 6fc5defcb1562..6d62f10416eb6 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3103,7 +3103,7 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) INIT_WORK(&ctx->exit_work, io_ring_exit_work); /* - * Use system_unbound_wq to avoid spawning tons of event kworkers + * Use system_dfl_wq to avoid spawning tons of event kworkers * if we're exiting a ton of rings at the same time. It just adds * noise and overhead, there's no discernable change in runtime * over using system_percpu_wq.