From 51aac424aef980a6238d4907a5bb5a411fa926eb Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 14 Oct 2021 16:10:17 +0100 Subject: io_uring: optimise io_import_iovec nonblock passing First, change IO_URING_F_NONBLOCK to take sign bit of the int, so checking for it can be turned into test + sign-based-jump, makes the binary smaller and may be faster. Then, instead of passing need_lock boolean into io_import_iovec() just give it issue_flags, which is already stored somewhere. Saves some space on stack, a couple of test + cmov operations and other conversions. note: we still leave force_nonblock = issue_flags & IO_URING_F_NONBLOCK variable, but it's optimised out by the compiler into testing issue_flags directly. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/ee96547e692f6c975c229cd82fc721679571a734.1634144845.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 47 +++++++++++++++++++++++++---------------------- 1 file changed, 25 insertions(+), 22 deletions(-) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index bb5cd8715f61..0a0f84b28eba 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -198,8 +198,9 @@ struct io_rings { }; enum io_uring_cmd_flags { - IO_URING_F_NONBLOCK = 1, - IO_URING_F_COMPLETE_DEFER = 2, + IO_URING_F_COMPLETE_DEFER = 1, + /* int's last bit, sign checks are usually faster than a bit test */ + IO_URING_F_NONBLOCK = INT_MIN, }; struct io_mapped_ubuf { @@ -3037,10 +3038,11 @@ static void io_ring_submit_lock(struct io_ring_ctx *ctx, bool needs_lock) } static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len, - int bgid, bool needs_lock) + int bgid, unsigned int issue_flags) { struct io_buffer *kbuf = req->kbuf; struct io_buffer *head; + bool needs_lock = !(issue_flags & IO_URING_F_NONBLOCK); if (req->flags & REQ_F_BUFFER_SELECTED) return kbuf; @@ -3072,13 +3074,13 @@ static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len, } static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len, - bool needs_lock) + unsigned int issue_flags) { struct io_buffer *kbuf; u16 bgid; bgid = req->buf_index; - kbuf = io_buffer_select(req, len, bgid, needs_lock); + kbuf = io_buffer_select(req, len, bgid, issue_flags); if (IS_ERR(kbuf)) return kbuf; return u64_to_user_ptr(kbuf->addr); @@ -3086,7 +3088,7 @@ static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len, #ifdef CONFIG_COMPAT static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov, - bool needs_lock) + unsigned int issue_flags) { struct compat_iovec __user *uiov; compat_ssize_t clen; @@ -3102,7 +3104,7 @@ static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov, return -EINVAL; len = clen; - buf = io_rw_buffer_select(req, &len, needs_lock); + buf = io_rw_buffer_select(req, &len, issue_flags); if (IS_ERR(buf)) return PTR_ERR(buf); iov[0].iov_base = buf; @@ -3112,7 +3114,7 @@ static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov, #endif static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, - bool needs_lock) + unsigned int issue_flags) { struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr); void __user *buf; @@ -3124,7 +3126,7 @@ static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, len = iov[0].iov_len; if (len < 0) return -EINVAL; - buf = io_rw_buffer_select(req, &len, needs_lock); + buf = io_rw_buffer_select(req, &len, issue_flags); if (IS_ERR(buf)) return PTR_ERR(buf); iov[0].iov_base = buf; @@ -3133,7 +3135,7 @@ static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, } static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, - bool needs_lock) + unsigned int issue_flags) { if (req->flags & REQ_F_BUFFER_SELECTED) { struct io_buffer *kbuf = req->kbuf; @@ -3147,14 +3149,14 @@ static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, #ifdef CONFIG_COMPAT if (req->ctx->compat) - return io_compat_import(req, iov, needs_lock); + return io_compat_import(req, iov, issue_flags); #endif - return __io_iov_buffer_select(req, iov, needs_lock); + return __io_iov_buffer_select(req, iov, issue_flags); } static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, - struct iov_iter *iter, bool needs_lock) + struct iov_iter *iter, unsigned int issue_flags) { void __user *buf = u64_to_user_ptr(req->rw.addr); size_t sqe_len = req->rw.len; @@ -3172,7 +3174,7 @@ static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) { if (req->flags & REQ_F_BUFFER_SELECT) { - buf = io_rw_buffer_select(req, &sqe_len, needs_lock); + buf = io_rw_buffer_select(req, &sqe_len, issue_flags); if (IS_ERR(buf)) return PTR_ERR(buf); req->rw.len = sqe_len; @@ -3184,7 +3186,7 @@ static int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, } if (req->flags & REQ_F_BUFFER_SELECT) { - ret = io_iov_buffer_select(req, *iovec, needs_lock); + ret = io_iov_buffer_select(req, *iovec, issue_flags); if (!ret) iov_iter_init(iter, rw, *iovec, 1, (*iovec)->iov_len); *iovec = NULL; @@ -3323,7 +3325,8 @@ static inline int io_rw_prep_async(struct io_kiocb *req, int rw) struct iovec *iov = iorw->s.fast_iov; int ret; - ret = io_import_iovec(rw, req, &iov, &iorw->s.iter, false); + /* submission path, ->uring_lock should already be taken */ + ret = io_import_iovec(rw, req, &iov, &iorw->s.iter, IO_URING_F_NONBLOCK); if (unlikely(ret < 0)) return ret; @@ -3451,7 +3454,7 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags) } else { s = &__s; iovec = s->fast_iov; - ret = io_import_iovec(READ, req, &iovec, &s->iter, !force_nonblock); + ret = io_import_iovec(READ, req, &iovec, &s->iter, issue_flags); if (ret < 0) return ret; @@ -3579,7 +3582,7 @@ static int io_write(struct io_kiocb *req, unsigned int issue_flags) } else { s = &__s; iovec = s->fast_iov; - ret = io_import_iovec(WRITE, req, &iovec, &s->iter, !force_nonblock); + ret = io_import_iovec(WRITE, req, &iovec, &s->iter, issue_flags); if (ret < 0) return ret; iov_iter_save_state(&s->iter, &s->iter_state); @@ -4902,11 +4905,11 @@ static int io_recvmsg_copy_hdr(struct io_kiocb *req, } static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req, - bool needs_lock) + unsigned int issue_flags) { struct io_sr_msg *sr = &req->sr_msg; - return io_buffer_select(req, &sr->len, sr->bgid, needs_lock); + return io_buffer_select(req, &sr->len, sr->bgid, issue_flags); } static inline unsigned int io_put_recv_kbuf(struct io_kiocb *req) @@ -4969,7 +4972,7 @@ static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) } if (req->flags & REQ_F_BUFFER_SELECT) { - kbuf = io_recv_buffer_select(req, !force_nonblock); + kbuf = io_recv_buffer_select(req, issue_flags); if (IS_ERR(kbuf)) return PTR_ERR(kbuf); kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr); @@ -5021,7 +5024,7 @@ static int io_recv(struct io_kiocb *req, unsigned int issue_flags) return -ENOTSOCK; if (req->flags & REQ_F_BUFFER_SELECT) { - kbuf = io_recv_buffer_select(req, !force_nonblock); + kbuf = io_recv_buffer_select(req, issue_flags); if (IS_ERR(kbuf)) return PTR_ERR(kbuf); buf = u64_to_user_ptr(kbuf->addr); -- cgit