Request completion is a very hot path in general, but there are 3 places
that can be doing it: io_free_batch_list(), io_req_complete_post() and
io_free_req_tw().
io_free_req_tw() is used rather marginally and we don't care about it.
Killing it can help to clean up and optimise the left two, do that by
replacing it with io_req_task_complete().
There are two things to consider:
1) io_free_req() is called when all refs are put, so we need to reinit
references. The easiest way to do that is to clear REQ_F_REFCOUNT.
2) We also don't need a cqe from it, so silence it with REQ_F_CQE_SKIP.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
io_uring/io_uring.c | 23 +++++------------------
1 file changed, 5 insertions(+), 18 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index b488a03ba009..43805d2621f5 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1121,26 +1121,13 @@ static inline void io_dismantle_req(struct io_kiocb *req)
io_put_file(req->file);
}
-static __cold void io_free_req_tw(struct io_kiocb *req, struct io_tw_state *ts)
-{
- struct io_ring_ctx *ctx = req->ctx;
-
- if (req->rsrc_node) {
- io_tw_lock(ctx, ts);
- io_put_rsrc_node(ctx, req->rsrc_node);
- }
- io_dismantle_req(req);
- io_put_task_remote(req->task, 1);
-
- spin_lock(&ctx->completion_lock);
- wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
- ctx->locked_free_nr++;
- spin_unlock(&ctx->completion_lock);
-}
-
__cold void io_free_req(struct io_kiocb *req)
{
- req->io_task_work.func = io_free_req_tw;
+ /* refs were already put, restore them for io_req_task_complete() */
+ req->flags &= ~REQ_F_REFCOUNT;
+ /* we only want to free it, don't post CQEs */
+ req->flags |= REQ_F_CQE_SKIP;
+ req->io_task_work.func = io_req_task_complete;
io_req_task_work_add(req);
}
--
2.40.0
