io_uring: optimise io_req_task_work_add()
Inline io_task_work_add() into io_req_task_work_add(). They both work
with a request, so keeping them separate doesn't make things much more
clear, but merging allows optimise it. Apart from small wins like not
reading req->ctx or not calculating @notify in the hot path, i.e. with
tctx->task_state set, it avoids doing wake_up_process() for every single
add, but only after actually done task_work_add().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6b805b1..7a6b2b3 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1911,13 +1911,17 @@ static void tctx_task_work(struct callback_head *cb)
cond_resched();
}
-static int io_task_work_add(struct task_struct *tsk, struct io_kiocb *req,
- enum task_work_notify_mode notify)
+static int io_req_task_work_add(struct io_kiocb *req)
{
+ struct task_struct *tsk = req->task;
struct io_uring_task *tctx = tsk->io_uring;
+ enum task_work_notify_mode notify;
struct io_wq_work_node *node, *prev;
unsigned long flags;
- int ret;
+ int ret = 0;
+
+ if (unlikely(tsk->flags & PF_EXITING))
+ return -ESRCH;
WARN_ON_ONCE(!tctx);
@@ -1930,14 +1934,23 @@ static int io_task_work_add(struct task_struct *tsk, struct io_kiocb *req,
test_and_set_bit(0, &tctx->task_state))
return 0;
- if (!task_work_add(tsk, &tctx->task_work, notify))
+ /*
+ * SQPOLL kernel thread doesn't need notification, just a wakeup. For
+ * all other cases, use TWA_SIGNAL unconditionally to ensure we're
+ * processing task_work. There's no reliable way to tell if TWA_RESUME
+ * will do the job.
+ */
+ notify = (req->ctx->flags & IORING_SETUP_SQPOLL) ? TWA_NONE : TWA_SIGNAL;
+
+ if (!task_work_add(tsk, &tctx->task_work, notify)) {
+ wake_up_process(tsk);
return 0;
+ }
/*
* Slow path - we failed, find and delete work. if the work is not
* in the list, it got run and we're fine.
*/
- ret = 0;
spin_lock_irqsave(&tctx->task_lock, flags);
wq_list_for_each(node, prev, &tctx->task_list) {
if (&req->io_task_work.node == node) {
@@ -1951,33 +1964,6 @@ static int io_task_work_add(struct task_struct *tsk, struct io_kiocb *req,
return ret;
}
-static int io_req_task_work_add(struct io_kiocb *req)
-{
- struct task_struct *tsk = req->task;
- struct io_ring_ctx *ctx = req->ctx;
- enum task_work_notify_mode notify;
- int ret;
-
- if (tsk->flags & PF_EXITING)
- return -ESRCH;
-
- /*
- * SQPOLL kernel thread doesn't need notification, just a wakeup. For
- * all other cases, use TWA_SIGNAL unconditionally to ensure we're
- * processing task_work. There's no reliable way to tell if TWA_RESUME
- * will do the job.
- */
- notify = TWA_NONE;
- if (!(ctx->flags & IORING_SETUP_SQPOLL))
- notify = TWA_SIGNAL;
-
- ret = io_task_work_add(tsk, req, notify);
- if (!ret)
- wake_up_process(tsk);
-
- return ret;
-}
-
static bool io_run_task_work_head(struct callback_head **work_head)
{
struct callback_head *work, *next;
