From 4fccfcbb733794634d4e873e7973c1847beca5bf Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 12 Feb 2021 11:55:17 +0000 Subject: [PATCH] io_uring: don't split out consume out of SQE get Remove io_consume_sqe() and inline it back into io_get_sqe(). It requires req dealloc on error, but in exchange we get cleaner io_submit_sqes() and better locality for cached_sq_head. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 87f2f8e660e8..9c58be0579f3 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6762,7 +6762,7 @@ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) * 2) allows the kernel side to track the head on its own, even * though the application is the one updating it. */ - head = READ_ONCE(sq_array[ctx->cached_sq_head & ctx->sq_mask]); + head = READ_ONCE(sq_array[ctx->cached_sq_head++ & ctx->sq_mask]); if (likely(head < ctx->sq_entries)) return &ctx->sq_sqes[head]; @@ -6772,11 +6772,6 @@ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) return NULL; } -static inline void io_consume_sqe(struct io_ring_ctx *ctx) -{ - ctx->cached_sq_head++; -} - /* * Check SQE restrictions (opcode and flags). * @@ -6915,18 +6910,17 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr) struct io_kiocb *req; int err; - sqe = io_get_sqe(ctx); - if (unlikely(!sqe)) { - io_consume_sqe(ctx); - break; - } req = io_alloc_req(ctx); if (unlikely(!req)) { if (!submitted) submitted = -EAGAIN; break; } - io_consume_sqe(ctx); + sqe = io_get_sqe(ctx); + if (unlikely(!sqe)) { + kmem_cache_free(req_cachep, req); + break; + } /* will complete beyond this point, count as submitted */ submitted++;