Commit 9333f6b4 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: thin down io_commit_cqring() 



io_commit_cqring() is currently always under spinlock section, so it's
always better to keep it as slim as possible. Move
__io_commit_cqring_flush() out of it into ev_posted*(). If fast checks
do fail and this post-processing is required, we'll reacquire
->completion_lock, which is fine as we don't care about performance of
draining and offset timeouts.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/ec4e81fd720d3bc7bca8cb9152e080dad1a052f1.1647481208.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 66fc25ca

fs/io_uring.c

+15 −8
Original line number Diff line number Diff line
@@ -1779,20 +1779,21 @@ static __cold void io_flush_timeouts(struct io_ring_ctx *ctx) 
	spin_unlock_irq(&ctx->timeout_lock);

}



static inline void io_commit_cqring(struct io_ring_ctx *ctx)

{

	/* order cqe stores with ring update */

	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);

}



static __cold void __io_commit_cqring_flush(struct io_ring_ctx *ctx)

{

	spin_lock(&ctx->completion_lock);

	if (ctx->off_timeout_used)

		io_flush_timeouts(ctx);

	if (ctx->drain_active)

		io_queue_deferred(ctx);

}



static inline void io_commit_cqring(struct io_ring_ctx *ctx)

{

	if (unlikely(ctx->off_timeout_used || ctx->drain_active))

		__io_commit_cqring_flush(ctx);

	/* order cqe stores with ring update */

	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);

	io_commit_cqring(ctx);

	spin_unlock(&ctx->completion_lock);

}



static inline bool io_sqring_full(struct io_ring_ctx *ctx)
@@ -1860,6 +1861,9 @@ static void io_eventfd_signal(struct io_ring_ctx *ctx) 
 */

static inline void io_cqring_ev_posted(struct io_ring_ctx *ctx)

{

	if (unlikely(ctx->off_timeout_used || ctx->drain_active))

		__io_commit_cqring_flush(ctx);



	/*

	 * wake_up_all() may seem excessive, but io_wake_function() and

	 * io_should_wake() handle the termination of the loop and only
@@ -1873,6 +1877,9 @@ static inline void io_cqring_ev_posted(struct io_ring_ctx *ctx) 


static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)

{

	if (unlikely(ctx->off_timeout_used || ctx->drain_active))

		__io_commit_cqring_flush(ctx);



	if (ctx->flags & IORING_SETUP_SQPOLL) {

		if (wq_has_sleeper(&ctx->cq_wait))

			wake_up_all(&ctx->cq_wait);