From: Hannes Reinecke <hare@suse.de>
To: Jens Axboe <axboe@kernel.dk>,
linux-aio@kvack.org, linux-block@vger.kernel.org,
linux-api@vger.kernel.org
Cc: hch@lst.de, jmoyer@redhat.com, avi@scylladb.com,
jannh@google.com, viro@ZenIV.linux.org.uk
Subject: Re: [PATCH 19/19] io_uring: add io_uring_event cache hit information
Date: Sun, 10 Feb 2019 10:36:57 +0100 [thread overview]
Message-ID: <ca60183a-bb43-930c-8bf1-026c2528723d@suse.de> (raw)
In-Reply-To: <20190209211346.26060-20-axboe@kernel.dk>
On 2/9/19 10:13 PM, Jens Axboe wrote:
> 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 <axboe@kernel.dk>
> ---
> 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 11a549b5dcbf..d7a10484d748 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -587,11 +587,16 @@ 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 e23408692118..24906e99fdc7 100644
> --- a/include/uapi/linux/io_uring.h
> +++ b/include/uapi/linux/io_uring.h
> @@ -69,6 +69,11 @@ struct io_uring_cqe {
> __u32 flags;
> };
>
> +/*
> + * io_uring_event->flags
> + */
> +#define IOCQE_FLAG_CACHEHIT (1U << 0) /* IO did not hit media */
> +
> /*
> * Magic offsets for the application to mmap the data it needs
> */
>
Hmm. The point of this patch being ... what?
Just setting a newly introduced flag seems to be a bit pointless.
Unless it has some magic interaction with io_cqring_add_event().
But then that function would have had to have knowledge of that flag
already, which would be ... odd.
Please clarify.
Cheers,
Hannes
next prev parent reply other threads:[~2019-02-10 9:37 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-09 21:13 [PATCHSET v14] io_uring IO interface Jens Axboe
2019-02-09 21:13 ` [PATCH 01/19] fs: add an iopoll method to struct file_operations Jens Axboe
2019-02-09 21:13 ` [PATCH 02/19] block: wire up block device iopoll method Jens Axboe
2019-02-09 21:13 ` [PATCH 03/19] block: add bio_set_polled() helper Jens Axboe
2019-02-09 21:13 ` [PATCH 04/19] iomap: wire up the iopoll method Jens Axboe
2019-02-09 21:13 ` [PATCH 05/19] Add io_uring IO interface Jens Axboe
2019-02-10 12:03 ` Thomas Gleixner
2019-02-10 14:19 ` Jens Axboe
2019-02-09 21:13 ` [PATCH 06/19] io_uring: add fsync support Jens Axboe
2019-02-09 21:13 ` [PATCH 07/19] io_uring: support for IO polling Jens Axboe
2019-02-09 21:13 ` [PATCH 08/19] fs: add fget_many() and fput_many() Jens Axboe
2019-02-09 21:13 ` [PATCH 09/19] io_uring: use fget/fput_many() for file references Jens Axboe
2019-02-09 21:13 ` [PATCH 10/19] io_uring: batch io_kiocb allocation Jens Axboe
2019-02-09 21:13 ` [PATCH 11/19] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2019-02-09 21:13 ` [PATCH 12/19] io_uring: add support for pre-mapped user IO buffers Jens Axboe
2019-02-09 21:13 ` [PATCH 13/19] net: split out functions related to registering inflight socket files Jens Axboe
2019-02-09 21:13 ` [PATCH 14/19] io_uring: add file set registration Jens Axboe
2019-02-09 23:52 ` Matt Mullins
2019-02-10 0:47 ` Jens Axboe
[not found] ` <60e4c6a489549daad1fb2c5e8eee5496c668d79a.camel@fb.com>
2019-02-10 2:34 ` Jens Axboe
2019-02-10 2:57 ` Jens Axboe
2019-02-10 19:55 ` Matt Mullins
2019-02-09 21:13 ` [PATCH 15/19] io_uring: add submission polling Jens Axboe
2019-02-09 21:13 ` [PATCH 16/19] io_uring: add io_kiocb ref count Jens Axboe
2019-02-10 9:19 ` Hannes Reinecke
2019-02-09 21:13 ` [PATCH 17/19] io_uring: add support for IORING_OP_POLL Jens Axboe
2019-02-10 9:28 ` Hannes Reinecke
2019-02-09 21:13 ` [PATCH 18/19] io_uring: allow workqueue item to handle multiple buffered requests Jens Axboe
2019-02-10 9:31 ` Hannes Reinecke
2019-02-09 21:13 ` [PATCH 19/19] io_uring: add io_uring_event cache hit information Jens Axboe
2019-02-10 9:36 ` Hannes Reinecke [this message]
2019-02-10 13:39 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2019-02-11 19:00 [PATCHSET v15] io_uring IO interface Jens Axboe
2019-02-11 19:00 ` [PATCH 19/19] io_uring: add io_uring_event cache hit information Jens Axboe
2019-02-08 17:34 [PATCHSET v13] io_uring IO interface Jens Axboe
2019-02-08 17:34 ` [PATCH 19/19] io_uring: add io_uring_event cache hit information Jens Axboe
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ca60183a-bb43-930c-8bf1-026c2528723d@suse.de \
--to=hare@suse.de \
--cc=avi@scylladb.com \
--cc=axboe@kernel.dk \
--cc=hch@lst.de \
--cc=jannh@google.com \
--cc=jmoyer@redhat.com \
--cc=linux-aio@kvack.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=viro@ZenIV.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).