From 81ea0ab0c08314ffad75f19ffc895bb0a71153cb Mon Sep 17 00:00:00 2001 From: Li Chen Date: Mon, 2 Feb 2026 22:37:54 +0800 Subject: io_uring: allow io-wq workers to exit when unused commit 91214661489467f8452d34edbf257488d85176e4 upstream. io_uring keeps a per-task io-wq around, even when the task no longer has any io_uring instances. If the task previously used io_uring for file I/O, this can leave an unrelated iou-wrk-* worker thread behind after the last io_uring instance is gone. When the last io_uring ctx is removed from the task context, mark the io-wq exit-on-idle so workers can go away. Clear the flag on subsequent io_uring usage. Signed-off-by: Li Chen Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/tctx.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'io_uring') diff --git a/io_uring/tctx.c b/io_uring/tctx.c index 6d6f44215ec8..91f4b830b77b 100644 --- a/io_uring/tctx.c +++ b/io_uring/tctx.c @@ -122,6 +122,14 @@ int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) return ret; } } + + /* + * Re-activate io-wq keepalive on any new io_uring usage. The wq may have + * been marked for idle-exit when the task temporarily had no active + * io_uring instances. + */ + if (tctx->io_wq) + io_wq_set_exit_on_idle(tctx->io_wq, false); if (!xa_load(&tctx->xa, (unsigned long)ctx)) { node = kmalloc(sizeof(*node), GFP_KERNEL); if (!node) @@ -183,6 +191,9 @@ __cold void io_uring_del_tctx_node(unsigned long index) if (tctx->last == node->ctx) tctx->last = NULL; kfree(node); + + if (xa_empty(&tctx->xa) && tctx->io_wq) + io_wq_set_exit_on_idle(tctx->io_wq, true); } __cold void io_uring_clean_tctx(struct io_uring_task *tctx) -- cgit v1.2.3