From 2fdd6fb5ff958a0f6b403e3f3ffd645b60b2a2b2 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 23 Jun 2023 12:23:25 +0100 Subject: [PATCH] io_uring: don't batch task put on reqs free We're trying to batch io_put_task() in io_free_batch_list(), but considering that the hot path is a simple inc, it's most cerainly and probably faster to just do io_put_task() instead of task tracking. We don't care about io_put_task_remote() as it's only for IOPOLL where polling/waiting is done by not the submitter task. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/4a7ef7dce845fe2bd35507bf389d6bd2d5c1edf0.1687518903.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/io_uring.c | 32 ++++++++++---------------------- 1 file changed, 10 insertions(+), 22 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 4d86139..3eec5c7 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -754,29 +754,29 @@ static void io_cqring_overflow_flush(struct io_ring_ctx *ctx) } /* can be called by any task */ -static void io_put_task_remote(struct task_struct *task, int nr) +static void io_put_task_remote(struct task_struct *task) { struct io_uring_task *tctx = task->io_uring; - percpu_counter_sub(&tctx->inflight, nr); + percpu_counter_sub(&tctx->inflight, 1); if (unlikely(atomic_read(&tctx->in_cancel))) wake_up(&tctx->wait); - put_task_struct_many(task, nr); + put_task_struct(task); } /* used by a task to put its own references */ -static void io_put_task_local(struct task_struct *task, int nr) +static void io_put_task_local(struct task_struct *task) { - task->io_uring->cached_refs += nr; + task->io_uring->cached_refs++; } /* must to be called somewhat shortly after putting a request */ -static inline void io_put_task(struct task_struct *task, int nr) +static inline void io_put_task(struct task_struct *task) { if (likely(task == current)) - io_put_task_local(task, nr); + io_put_task_local(task); else - io_put_task_remote(task, nr); + io_put_task_remote(task); } void io_task_refs_refill(struct io_uring_task *tctx) @@ -1033,7 +1033,7 @@ static void __io_req_complete_post(struct io_kiocb *req, unsigned issue_flags) * we don't hold ->completion_lock. Clean them here to avoid * deadlocks. */ - io_put_task_remote(req->task, 1); + io_put_task_remote(req->task); wq_list_add_head(&req->comp_list, &ctx->locked_free_list); ctx->locked_free_nr++; } @@ -1518,9 +1518,6 @@ void io_queue_next(struct io_kiocb *req) void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node) __must_hold(&ctx->uring_lock) { - struct task_struct *task = NULL; - int task_refs = 0; - do { struct io_kiocb *req = container_of(node, struct io_kiocb, comp_list); @@ -1550,19 +1547,10 @@ void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node) io_req_put_rsrc_locked(req, ctx); - if (req->task != task) { - if (task) - io_put_task(task, task_refs); - task = req->task; - task_refs = 0; - } - task_refs++; + io_put_task(req->task); node = req->comp_list.next; io_req_add_to_cache(req, ctx); } while (node); - - if (task) - io_put_task(task, task_refs); } static void __io_submit_flush_completions(struct io_ring_ctx *ctx) -- 2.7.4