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).
Signed-off-by: Jens Axboe <[email protected]> --- fs/io_uring.c | 6 +++++- include/uapi/linux/io_uring.h | 5 +++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6c10841e4342..50b9cfa8c861 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -524,12 +524,16 @@ static void io_fill_cq_error(struct io_ring_ctx *ctx, unsigned ki_index, static void io_complete_scqring_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *iocb = container_of(kiocb, struct io_kiocb, rw); + unsigned ev_flags = 0; kiocb_end_write(kiocb); fput(kiocb->ki_filp); - io_complete_scqring(iocb, res, 0); + if (res > 0 && test_bit(KIOCB_F_FORCE_NONBLOCK, &iocb->ki_flags)) + ev_flags = IOEV_FLAG_CACHEHIT; + + io_complete_scqring(iocb, res, ev_flags); } static void io_complete_scqring_iopoll(struct kiocb *kiocb, long res, long res2) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index bd665d38dd97..7dd21126f142 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -56,6 +56,11 @@ struct io_uring_event { __u32 flags; }; +/* + * io_uring_event->flags + */ +#define IOEV_FLAG_CACHEHIT (1 << 0) /* IO did not hit media */ + /* * Magic offsets for the application to mmap the data it needs */ -- 2.17.1
