From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: [PATCH 18/18] io_uring: add io_uring_event cache hit information Date: Mon, 28 Jan 2019 14:35:38 -0700 Message-ID: <20190128213538.13486-19-axboe@kernel.dk> References: <20190128213538.13486-1-axboe@kernel.dk> Return-path: In-Reply-To: <20190128213538.13486-1-axboe@kernel.dk> Sender: owner-linux-aio@kvack.org To: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com, Jens Axboe List-Id: linux-man@vger.kernel.org Add hint on whether a read was served out of the page cache, or if it hit media. This is useful for buffered async IO, O_DIRECT reads would never have this set (for obvious reasons). If the read hit page cache, cqe->flags will have IOCQE_FLAG_CACHEHIT set. Signed-off-by: Jens Axboe --- fs/io_uring.c | 7 ++++++- include/uapi/linux/io_uring.h | 5 +++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 0240e0a04f6a..9b4b4f9d06a5 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -558,11 +558,16 @@ static void io_fput(struct io_kiocb *req) static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); + unsigned ev_flags = 0; kiocb_end_write(kiocb); io_fput(req); - io_cqring_add_event(req->ctx, req->user_data, res, 0); + + if (res > 0 && (req->flags & REQ_F_FORCE_NONBLOCK)) + ev_flags = IOCQE_FLAG_CACHEHIT; + + io_cqring_add_event(req->ctx, req->user_data, res, ev_flags); io_free_req(req); } diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 39d3d3336dce..589b6402081d 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -71,6 +71,11 @@ struct io_uring_cqe { __u32 flags; }; +/* + * io_uring_event->flags + */ +#define IOCQE_FLAG_CACHEHIT (1 << 0) /* IO did not hit media */ + /* * Magic offsets for the application to mmap the data it needs */ -- 2.17.1 -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@kvack.org. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: aart@kvack.org