Re: [PATCH v3 4/4] io_uring: add support for zone-append
From: Jens Axboe <axboe@kernel.dk>
Date: 2020-07-05 21:00:52
Also in:
io-uring, linux-fsdevel, lkml
On 7/5/20 12:47 PM, Kanchan Joshi wrote:
quoted hunk ↗ jump to hunk
From: Selvakumar S <redacted> For zone-append, block-layer will return zone-relative offset via ret2 of ki_complete interface. Make changes to collect it, and send to user-space using cqe->flags. Signed-off-by: Selvakumar S <redacted> Signed-off-by: Kanchan Joshi <redacted> Signed-off-by: Nitesh Shetty <redacted> Signed-off-by: Javier Gonzalez <redacted> --- fs/io_uring.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)diff --git a/fs/io_uring.c b/fs/io_uring.c index 155f3d8..cbde4df 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c@@ -402,6 +402,8 @@ struct io_rw { struct kiocb kiocb; u64 addr; u64 len; + /* zone-relative offset for append, in sectors */ + u32 append_offset; };
I don't like this very much at all. As it stands, the first cacheline of io_kiocb is set aside for request-private data. io_rw is already exactly 64 bytes, which means that you're now growing io_rw beyond a cacheline and increasing the size of io_kiocb as a whole. Maybe you can reuse io_rw->len for this, as that is only used on the submission side of things. -- Jens Axboe