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io_uring: optimise iowq refcounting

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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
1 changed files with 16 additions and 9 deletions
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25
fs/io_uring.c
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@ -1115,14 +1115,19 @@ static inline void req_ref_get(struct io_kiocb *req)
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)) {
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)
{
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;
/* linked timeouts should have two refs once prep'ed */
io_req_refcount(req);
io_req_refcount(nxt);
io_req_set_refcount(req);
io_req_set_refcount(nxt);
req_ref_get(nxt);
nxt->timeout.head = req;
@ -5233,7 +5238,7 @@ static int io_arm_poll_handler(struct io_kiocb *req)
req->apoll = apoll;
req->flags |= REQ_F_POLLED;
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,
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)
return -EINVAL;
io_req_refcount(req);
io_req_set_refcount(req);
poll->events = io_poll_parse_events(sqe, flags);
return 0;
}
@ -6313,9 +6318,11 @@ static void io_wq_submit_work(struct io_wq_work *work)
struct io_kiocb *timeout;
int ret = 0;
io_req_refcount(req);
/* will be dropped by ->io_free_work() after returning to io-wq */
req_ref_get(req);
/* one will be dropped by ->io_free_work() after returning to io-wq */
if (!(req->flags & REQ_F_REFCOUNT))
__io_req_set_refcount(req, 2);
else
req_ref_get(req);
timeout = io_prep_linked_timeout(req);
if (timeout)