io_uring: submit-completion free batching

io_submit_flush_completions() does completion batching, but may also use
free batching as iopoll does. The main beneficiaries should be buffered
reads/writes and send/recv.

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 aef6406..885dd16 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1924,26 +1924,6 @@ static inline void io_req_complete_nostate(struct io_kiocb *req, long res,
        io_put_req(req);
 }
 
-static void io_submit_flush_completions(struct io_comp_state *cs,
-                                       struct io_ring_ctx *ctx)
-{
-       int i, nr = cs->nr;
-
-       spin_lock_irq(&ctx->completion_lock);
-       for (i = 0; i < nr; i++) {
-               struct io_kiocb *req = cs->reqs[i];
-
-               __io_cqring_fill_event(req, req->result, req->compl.cflags);
-       }
-       io_commit_cqring(ctx);
-       spin_unlock_irq(&ctx->completion_lock);
-
-       io_cqring_ev_posted(ctx);
-       for (i = 0; i < nr; i++)
-               io_double_put_req(cs->reqs[i]);
-       cs->nr = 0;
-}
-
 static void io_req_complete_state(struct io_kiocb *req, long res,
                                  unsigned int cflags)
 {
@@ -2329,6 +2309,35 @@ static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req)
                __io_req_free_batch_flush(req->ctx, rb);
 }
 
+static void io_submit_flush_completions(struct io_comp_state *cs,
+                                       struct io_ring_ctx *ctx)
+{
+       int i, nr = cs->nr;
+       struct io_kiocb *req;
+       struct req_batch rb;
+
+       io_init_req_batch(&rb);
+       spin_lock_irq(&ctx->completion_lock);
+       for (i = 0; i < nr; i++) {
+               req = cs->reqs[i];
+               __io_cqring_fill_event(req, req->result, req->compl.cflags);
+       }
+       io_commit_cqring(ctx);
+       spin_unlock_irq(&ctx->completion_lock);
+
+       io_cqring_ev_posted(ctx);
+       for (i = 0; i < nr; i++) {
+               req = cs->reqs[i];
+
+               /* submission and completion refs */
+               if (refcount_sub_and_test(2, &req->refs))
+                       io_req_free_batch(&rb, req);
+       }
+
+       io_req_free_batch_finish(ctx, &rb);
+       cs->nr = 0;
+}
+
 /*
  * Drop reference to request, return next in chain (if there is one) if this
  * was the last reference to this request.