io_uring: switch !DRAIN fast path when possible
->drain_used is one way, which is not optimal if users use DRAIN but
very rarely. However, we can just clear it in io_drain_req() when all
drained before requests are gone. Also rename the flag to reflect the
change and be more clear about it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7f37a240857546a94df6348507edddacab150460.1623772051.git.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 6292b8d..25106cf 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -352,7 +352,7 @@ struct io_ring_ctx {
unsigned int eventfd_async: 1;
unsigned int restricted: 1;
unsigned int off_timeout_used: 1;
- unsigned int drain_used: 1;
+ unsigned int drain_active: 1;
} ____cacheline_aligned_in_smp;
/* submission data */
@@ -1346,10 +1346,10 @@ static void io_flush_timeouts(struct io_ring_ctx *ctx)
static void io_commit_cqring(struct io_ring_ctx *ctx)
{
- if (unlikely(ctx->off_timeout_used || ctx->drain_used)) {
+ if (unlikely(ctx->off_timeout_used || ctx->drain_active)) {
if (ctx->off_timeout_used)
io_flush_timeouts(ctx);
- if (ctx->drain_used)
+ if (ctx->drain_active)
io_queue_deferred(ctx);
}
/* order cqe stores with ring update */
@@ -6004,8 +6004,10 @@ static bool io_drain_req(struct io_kiocb *req)
/* Still need defer if there is pending req in defer list. */
if (likely(list_empty_careful(&ctx->defer_list) &&
- !(req->flags & REQ_F_IO_DRAIN)))
+ !(req->flags & REQ_F_IO_DRAIN))) {
+ ctx->drain_active = false;
return false;
+ }
seq = io_get_sequence(req);
/* Still a chance to pass the sequence check */
@@ -6446,7 +6448,7 @@ static void __io_queue_sqe(struct io_kiocb *req)
static inline void io_queue_sqe(struct io_kiocb *req)
{
- if (unlikely(req->ctx->drain_used) && io_drain_req(req))
+ if (unlikely(req->ctx->drain_active) && io_drain_req(req))
return;
if (likely(!(req->flags & REQ_F_FORCE_ASYNC))) {
@@ -6572,7 +6574,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
}
if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
- ctx->drain_used = true;
+ ctx->drain_active = true;
/*
* Taking sequential execution of a link, draining both sides
