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From: Jens Axboe <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>
Subject: [PATCH 1/3] io_uring: add remote task_work execution helper
Date: Fri, 29 Mar 2024 14:09:28 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

All our task_work handling is targeted at the state in the io_kiocb
itself, which is what it is being used for. However, MSG_RING rolls its
own task_work handling, ignoring how that is usually done.

In preparation for switching MSG_RING to be able to use the normal
task_work handling, add io_req_task_work_add_remote() which allows the
caller to pass in the target io_ring_ctx.

Signed-off-by: Jens Axboe <[email protected]>
---
 io_uring/io_uring.c | 30 ++++++++++++++++++++++--------
 io_uring/io_uring.h |  2 ++
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index fddaefb9cbff..a311a244914b 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1232,9 +1232,10 @@ void tctx_task_work(struct callback_head *cb)
 	WARN_ON_ONCE(ret);
 }
 
-static inline void io_req_local_work_add(struct io_kiocb *req, unsigned flags)
+static inline void io_req_local_work_add(struct io_kiocb *req,
+					 struct io_ring_ctx *ctx,
+					 unsigned flags)
 {
-	struct io_ring_ctx *ctx = req->ctx;
 	unsigned nr_wait, nr_tw, nr_tw_prev;
 	struct llist_node *head;
 
@@ -1300,9 +1301,10 @@ static inline void io_req_local_work_add(struct io_kiocb *req, unsigned flags)
 	wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);
 }
 
-static void io_req_normal_work_add(struct io_kiocb *req)
+static void io_req_normal_work_add(struct io_kiocb *req,
+				   struct task_struct *task)
 {
-	struct io_uring_task *tctx = req->task->io_uring;
+	struct io_uring_task *tctx = task->io_uring;
 	struct io_ring_ctx *ctx = req->ctx;
 
 	/* task_work already pending, we're done */
@@ -1321,7 +1323,7 @@ static void io_req_normal_work_add(struct io_kiocb *req)
 		return;
 	}
 
-	if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))
+	if (likely(!task_work_add(task, &tctx->task_work, ctx->notify_method)))
 		return;
 
 	io_fallback_tw(tctx, false);
@@ -1331,10 +1333,22 @@ void __io_req_task_work_add(struct io_kiocb *req, unsigned flags)
 {
 	if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
 		rcu_read_lock();
-		io_req_local_work_add(req, flags);
+		io_req_local_work_add(req, req->ctx, flags);
+		rcu_read_unlock();
+	} else {
+		io_req_normal_work_add(req, req->task);
+	}
+}
+
+void io_req_task_work_add_remote(struct io_kiocb *req, struct io_ring_ctx *ctx,
+				 unsigned flags)
+{
+	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
+		rcu_read_lock();
+		io_req_local_work_add(req, ctx, flags);
 		rcu_read_unlock();
 	} else {
-		io_req_normal_work_add(req);
+		io_req_normal_work_add(req, READ_ONCE(ctx->submitter_task));
 	}
 }
 
@@ -1348,7 +1362,7 @@ static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
 						    io_task_work.node);
 
 		node = node->next;
-		io_req_normal_work_add(req);
+		io_req_normal_work_add(req, req->task);
 	}
 }
 
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 1eb65324792a..4155379ee586 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -74,6 +74,8 @@ struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
 			       unsigned issue_flags);
 
 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
+void io_req_task_work_add_remote(struct io_kiocb *req, struct io_ring_ctx *ctx,
+				 unsigned flags);
 bool io_alloc_async_data(struct io_kiocb *req);
 void io_req_task_queue(struct io_kiocb *req);
 void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
-- 
2.43.0


  reply	other threads:[~2024-03-29 20:12 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-03-29 20:09 [PATCHSET v2 0/3] Cleanup and improve MSG_RING performance Jens Axboe
2024-03-29 20:09 ` Jens Axboe [this message]
2024-04-01 17:30   ` [PATCH 1/3] io_uring: add remote task_work execution helper David Wei
2024-04-01 18:02     ` Jens Axboe
2024-03-29 20:09 ` [PATCH 2/3] io_uring/msg_ring: cleanup posting to IOPOLL vs !IOPOLL ring Jens Axboe
2024-03-29 20:09 ` [PATCH 3/3] io_uring/msg_ring: improve handling of target CQE posting Jens Axboe
2024-04-01 17:57   ` David Wei
  -- strict thread matches above, loose matches on Subject: below --
2024-03-28 18:52 [PATCHSET 0/3] Cleanup and improve MSG_RING performance Jens Axboe
2024-03-28 18:52 ` [PATCH 1/3] io_uring: add remote task_work execution helper Jens Axboe
2024-03-29 12:51   ` Pavel Begunkov
2024-03-29 13:31     ` Jens Axboe
2024-03-29 15:50       ` Pavel Begunkov
2024-03-29 16:10         ` Jens Axboe

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