io_uring: merge conditional unlock flush helpers

There is no reason not to use __io_cq_unlock_post_flush for intermediate
aux CQE flushing, all ->task_complete should apply there, i.e. if set it
should be the submitter task. Combine them, get rid of of
__io_cq_unlock_post() and rename the left function.

This place was also taking a couple percents of CPU according to
profiles for max throughput net benchmarks due to multishot recv
flooding it with completions.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bbed60734cbec2e833d9c7bdcf9741aada5d8aab.1687518903.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 70fffed..1b53a2a 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -637,20 +637,9 @@ static inline void io_cq_lock(struct io_ring_ctx *ctx)
        spin_lock(&ctx->completion_lock);
 }
 
-/* keep it inlined for io_submit_flush_completions() */
 static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
 {
        io_commit_cqring(ctx);
-       if (!ctx->task_complete)
-               spin_unlock(&ctx->completion_lock);
-
-       io_commit_cqring_flush(ctx);
-       io_cqring_wake(ctx);
-}
-
-static void __io_cq_unlock_post_flush(struct io_ring_ctx *ctx)
-{
-       io_commit_cqring(ctx);
 
        if (ctx->task_complete) {
                /*
@@ -1568,7 +1557,7 @@ static void __io_submit_flush_completions(struct io_ring_ctx *ctx)
                        }
                }
        }
-       __io_cq_unlock_post_flush(ctx);
+       __io_cq_unlock_post(ctx);
 
        if (!wq_list_empty(&ctx->submit_state.compl_reqs)) {
                io_free_batch_list(ctx, state->compl_reqs.first);