Commit 5af1d13e authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: batch put_task_struct() 



As every iopoll request have a task ref, it becomes expensive to put
them one by one, instead we can put several at once integrating that
into io_req_free_batch().

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent dd6f843a

fs/io_uring.c

+27 −2
Original line number Diff line number Diff line
@@ -1544,7 +1544,6 @@ static void io_dismantle_req(struct io_kiocb *req) 
		kfree(req->io);

	if (req->file)

		io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));

	__io_put_req_task(req);

	io_req_clean_work(req);



	if (req->flags & REQ_F_INFLIGHT) {
@@ -1564,6 +1563,7 @@ static void __io_free_req(struct io_kiocb *req) 
	struct io_ring_ctx *ctx;



	io_dismantle_req(req);

	__io_put_req_task(req);

	ctx = req->ctx;

	if (likely(!io_is_fallback_req(req)))

		kmem_cache_free(req_cachep, req);
@@ -1807,8 +1807,18 @@ static void io_free_req(struct io_kiocb *req) 
struct req_batch {

	void *reqs[IO_IOPOLL_BATCH];

	int to_free;



	struct task_struct	*task;

	int			task_refs;

};



static inline void io_init_req_batch(struct req_batch *rb)

{

	rb->to_free = 0;

	rb->task_refs = 0;

	rb->task = NULL;

}



static void __io_req_free_batch_flush(struct io_ring_ctx *ctx,

				      struct req_batch *rb)

{
@@ -1822,6 +1832,10 @@ static void io_req_free_batch_finish(struct io_ring_ctx *ctx, 
{

	if (rb->to_free)

		__io_req_free_batch_flush(ctx, rb);

	if (rb->task) {

		put_task_struct_many(rb->task, rb->task_refs);

		rb->task = NULL;

	}

}



static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req)
@@ -1833,6 +1847,17 @@ static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req) 
	if (req->flags & REQ_F_LINK_HEAD)

		io_queue_next(req);



	if (req->flags & REQ_F_TASK_PINNED) {

		if (req->task != rb->task) {

			if (rb->task)

				put_task_struct_many(rb->task, rb->task_refs);

			rb->task = req->task;

			rb->task_refs = 0;

		}

		rb->task_refs++;

		req->flags &= ~REQ_F_TASK_PINNED;

	}



	io_dismantle_req(req);

	rb->reqs[rb->to_free++] = req;

	if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs)))
@@ -1978,7 +2003,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, 
	/* order with ->result store in io_complete_rw_iopoll() */

	smp_rmb();



	rb.to_free = 0;

	io_init_req_batch(&rb);

	while (!list_empty(done)) {

		int cflags = 0;