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io_uring: optimise fill_event() by inlining 

There are three cases where we much care about performance of
io_cqring_fill_event() -- flushing inline completions, iopoll and
io_req_complete_post(). Inline a hot part of fill_event() into them.

All others are not as important and we don't want to bloat binary for
them, so add a noinline version of the function for all other use
use cases.

nops test(batch=32): 16.932 vs 17.822 KIOPS

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a11d59424bf4417aca33f5ec21008bb3b0ebd11e.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-04-11 01:46:33 +01:00 committed by Jens Axboe
parent ff64216423
commit 8d13326e56
1 changed files with 36 additions and 21 deletions
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57
fs/io_uring.c
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@ -1336,7 +1336,7 @@ static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
}
static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
static inline struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
unsigned tail;
@ -1492,26 +1492,11 @@ static inline void req_ref_get(struct io_kiocb *req)
atomic_inc(&req->refs);
}
static bool io_cqring_fill_event(struct io_kiocb *req, long res,
unsigned int cflags)
static bool io_cqring_event_overflow(struct io_kiocb *req, long res,
unsigned int cflags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_uring_cqe *cqe;
trace_io_uring_complete(ctx, req->user_data, res, cflags);
/*
* If we can't get a cq entry, userspace overflowed the
* submission (by quite a lot). Increment the overflow count in
* the ring.
*/
cqe = io_get_cqring(ctx);
if (likely(cqe)) {
WRITE_ONCE(cqe->user_data, req->user_data);
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, cflags);
return true;
}
if (!atomic_read(&req->task->io_uring->in_idle)) {
struct io_overflow_cqe *ocqe;
@ -1539,6 +1524,36 @@ overflow:
return false;
}
static inline bool __io_cqring_fill_event(struct io_kiocb *req, long res,
unsigned int cflags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_uring_cqe *cqe;
trace_io_uring_complete(ctx, req->user_data, res, cflags);
/*
* If we can't get a cq entry, userspace overflowed the
* submission (by quite a lot). Increment the overflow count in
* the ring.
*/
cqe = io_get_cqring(ctx);
if (likely(cqe)) {
WRITE_ONCE(cqe->user_data, req->user_data);
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, cflags);
return true;
}
return io_cqring_event_overflow(req, res, cflags);
}
/* not as hot to bloat with inlining */
static noinline bool io_cqring_fill_event(struct io_kiocb *req, long res,
unsigned int cflags)
{
return __io_cqring_fill_event(req, res, cflags);
}
static void io_req_complete_post(struct io_kiocb *req, long res,
unsigned int cflags)
{
@ -1546,7 +1561,7 @@ static void io_req_complete_post(struct io_kiocb *req, long res,
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
io_cqring_fill_event(req, res, cflags);
__io_cqring_fill_event(req, res, cflags);
/*
* If we're the last reference to this request, add to our locked
* free_list cache.
@ -2101,7 +2116,7 @@ static void io_submit_flush_completions(struct io_comp_state *cs,
spin_lock_irq(&ctx->completion_lock);
for (i = 0; i < nr; i++) {
req = cs->reqs[i];
io_cqring_fill_event(req, req->result, req->compl.cflags);
__io_cqring_fill_event(req, req->result, req->compl.cflags);
}
io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);
@ -2241,7 +2256,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
if (req->flags & REQ_F_BUFFER_SELECTED)
cflags = io_put_rw_kbuf(req);
io_cqring_fill_event(req, req->result, cflags);
__io_cqring_fill_event(req, req->result, cflags);
(*nr_events)++;
if (req_ref_put_and_test(req))