io_uring: optimise iowq refcounting

If a requests is forwarded into io-wq, there is a good chance it hasn't
been refcounted yet and we can save one req_ref_get() by setting the
refcount number to the right value directly.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/2d53f4449faaf73b4a4c5de667fc3c176d974860.1628981736.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-08-15 10:40:18 +01:00 committed by Jens Axboe
parent a141dd896f
commit 48dcd38d73

View File

@ -1115,14 +1115,19 @@ static inline void req_ref_get(struct io_kiocb *req)
atomic_inc(&req->refs); atomic_inc(&req->refs);
} }
static inline void io_req_refcount(struct io_kiocb *req) static inline void __io_req_set_refcount(struct io_kiocb *req, int nr)
{ {
if (!(req->flags & REQ_F_REFCOUNT)) { if (!(req->flags & REQ_F_REFCOUNT)) {
req->flags |= REQ_F_REFCOUNT; req->flags |= REQ_F_REFCOUNT;
atomic_set(&req->refs, 1); atomic_set(&req->refs, nr);
} }
} }
static inline void io_req_set_refcount(struct io_kiocb *req)
{
__io_req_set_refcount(req, 1);
}
static inline void io_req_set_rsrc_node(struct io_kiocb *req) static inline void io_req_set_rsrc_node(struct io_kiocb *req)
{ {
struct io_ring_ctx *ctx = req->ctx; struct io_ring_ctx *ctx = req->ctx;
@ -1306,8 +1311,8 @@ static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
return NULL; return NULL;
/* linked timeouts should have two refs once prep'ed */ /* linked timeouts should have two refs once prep'ed */
io_req_refcount(req); io_req_set_refcount(req);
io_req_refcount(nxt); io_req_set_refcount(nxt);
req_ref_get(nxt); req_ref_get(nxt);
nxt->timeout.head = req; nxt->timeout.head = req;
@ -5233,7 +5238,7 @@ static int io_arm_poll_handler(struct io_kiocb *req)
req->apoll = apoll; req->apoll = apoll;
req->flags |= REQ_F_POLLED; req->flags |= REQ_F_POLLED;
ipt.pt._qproc = io_async_queue_proc; ipt.pt._qproc = io_async_queue_proc;
io_req_refcount(req); io_req_set_refcount(req);
ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask, ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
io_async_wake); io_async_wake);
@ -5421,7 +5426,7 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe
if (flags & ~IORING_POLL_ADD_MULTI) if (flags & ~IORING_POLL_ADD_MULTI)
return -EINVAL; return -EINVAL;
io_req_refcount(req); io_req_set_refcount(req);
poll->events = io_poll_parse_events(sqe, flags); poll->events = io_poll_parse_events(sqe, flags);
return 0; return 0;
} }
@ -6313,9 +6318,11 @@ static void io_wq_submit_work(struct io_wq_work *work)
struct io_kiocb *timeout; struct io_kiocb *timeout;
int ret = 0; int ret = 0;
io_req_refcount(req); /* one will be dropped by ->io_free_work() after returning to io-wq */
/* will be dropped by ->io_free_work() after returning to io-wq */ if (!(req->flags & REQ_F_REFCOUNT))
req_ref_get(req); __io_req_set_refcount(req, 2);
else
req_ref_get(req);
timeout = io_prep_linked_timeout(req); timeout = io_prep_linked_timeout(req);
if (timeout) if (timeout)