From 7f00651aebc9af600be1d9df2a775eeeaee6bebb Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 14 Apr 2021 13:38:34 +0100 Subject: [PATCH] io_uring: refactor io_ring_exit_work() Don't reinit io_ring_exit_work()'s exit work/completions on each iteration, that's wasteful. Also add list_rotate_left(), so if we failed to complete the task job, we don't try it again and again but defer it until others are processed. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index a807c3f22778..f0e6349f9919 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8575,6 +8575,9 @@ static void io_ring_exit_work(struct work_struct *work) WARN_ON_ONCE(time_after(jiffies, timeout)); } while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20)); + init_completion(&exit.completion); + init_task_work(&exit.task_work, io_tctx_exit_cb); + exit.ctx = ctx; /* * Some may use context even when all refs and requests have been put, * and they are free to do so while still holding uring_lock or @@ -8587,9 +8590,8 @@ static void io_ring_exit_work(struct work_struct *work) node = list_first_entry(&ctx->tctx_list, struct io_tctx_node, ctx_node); - exit.ctx = ctx; - init_completion(&exit.completion); - init_task_work(&exit.task_work, io_tctx_exit_cb); + /* don't spin on a single task if cancellation failed */ + list_rotate_left(&ctx->tctx_list); ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL); if (WARN_ON_ONCE(ret)) continue; @@ -8597,7 +8599,6 @@ static void io_ring_exit_work(struct work_struct *work) mutex_unlock(&ctx->uring_lock); wait_for_completion(&exit.completion); - cond_resched(); mutex_lock(&ctx->uring_lock); } mutex_unlock(&ctx->uring_lock);