Commit 9f010507 authored by Jens Axboe's avatar Jens Axboe

io_uring: set task_work notify method at init time

While doing so, switch SQPOLL to TWA_SIGNAL_NO_IPI as well, as that
just does a task wakeup and then we can remove the special wakeup we
have in task_work_add.
Reviewed-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-5-axboe@kernel.dkSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 6cf5862e
...@@ -366,6 +366,7 @@ struct io_ring_ctx { ...@@ -366,6 +366,7 @@ struct io_ring_ctx {
struct io_rings *rings; struct io_rings *rings;
unsigned int flags; unsigned int flags;
enum task_work_notify_mode notify_method;
unsigned int compat: 1; unsigned int compat: 1;
unsigned int drain_next: 1; unsigned int drain_next: 1;
unsigned int restricted: 1; unsigned int restricted: 1;
...@@ -2621,8 +2622,8 @@ static void tctx_task_work(struct callback_head *cb) ...@@ -2621,8 +2622,8 @@ static void tctx_task_work(struct callback_head *cb)
static void io_req_task_work_add(struct io_kiocb *req, bool priority) static void io_req_task_work_add(struct io_kiocb *req, bool priority)
{ {
struct task_struct *tsk = req->task; struct task_struct *tsk = req->task;
struct io_ring_ctx *ctx = req->ctx;
struct io_uring_task *tctx = tsk->io_uring; struct io_uring_task *tctx = tsk->io_uring;
enum task_work_notify_mode notify;
struct io_wq_work_node *node; struct io_wq_work_node *node;
unsigned long flags; unsigned long flags;
bool running; bool running;
...@@ -2645,18 +2646,8 @@ static void io_req_task_work_add(struct io_kiocb *req, bool priority) ...@@ -2645,18 +2646,8 @@ static void io_req_task_work_add(struct io_kiocb *req, bool priority)
if (running) if (running)
return; return;
/* if (likely(!task_work_add(tsk, &tctx->task_work, ctx->notify_method)))
* 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 (likely(!task_work_add(tsk, &tctx->task_work, notify))) {
if (notify == TWA_NONE)
wake_up_process(tsk);
return; return;
}
spin_lock_irqsave(&tctx->task_lock, flags); spin_lock_irqsave(&tctx->task_lock, flags);
tctx->task_running = false; tctx->task_running = false;
...@@ -11335,6 +11326,14 @@ static __cold int io_uring_create(unsigned entries, struct io_uring_params *p, ...@@ -11335,6 +11326,14 @@ static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
if (!capable(CAP_IPC_LOCK)) if (!capable(CAP_IPC_LOCK))
ctx->user = get_uid(current_user()); ctx->user = get_uid(current_user());
/*
* For SQPOLL, we just need a wakeup, always.
*/
if (ctx->flags & IORING_SETUP_SQPOLL)
ctx->notify_method = TWA_SIGNAL_NO_IPI;
else
ctx->notify_method = TWA_SIGNAL;
/* /*
* This is just grabbed for accounting purposes. When a process exits, * This is just grabbed for accounting purposes. When a process exits,
* the mm is exited and dropped before the files, hence we need to hang * the mm is exited and dropped before the files, hence we need to hang
......
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