Re: [PATCH v2 0/2] async hybrid for pollable requests

[Pavel Begunkov <asml.silence@gmail.com>]

On 10/18/21 11:29, Hao Xu wrote:
> 1/2 is a prep patch. 2/2 is the main one.
> The good thing: see commit message.
> the side effect: for normal io-worker path, added two if and two local
> variables. for FORCE_ASYNC path, added three if and several dereferences
> 
> I think it is fine since the io-worker path is not the fast path, and
> the benefit of this patchset is worth it.

We don't care about overhead in iowq, but would be better to get rid
of the in_worker in io_read(). See comments to 1/2.

Btw, you told that it performs better comparing to normal
IOSQE_ASYNC. I'm confused, didn't we agree that it can be
merged into IOSQE_ASYNC without extra flags?

> 
> Btw, we need to tweak the io-cancel.c a bit, not a big problem.
> liburing tests will come later.
> 
> v1-->v2:
>   - split logic of force_nonblock
>   - tweak added code in io_wq_submit_work to reduce overhead
>   from Pavel's commments.
> 
> Hao Xu (2):
>    io_uring: split logic of force_nonblock
>    io_uring: implement async hybrid mode for pollable requests
> 
>   fs/io_uring.c                 | 85 ++++++++++++++++++++++++++---------
>   include/uapi/linux/io_uring.h |  4 +-
>   2 files changed, 66 insertions(+), 23 deletions(-)
> 

-- 
Pavel Begunkov