Re: [PATCH 0/2] improve SQPOLL handling

[Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>]

hello,

This is a gentle ping.

Regards,
Xiaogaung Wang

> The first patch tries to improve various issues in current implementation:
>    The prepare_to_wait() usage in __io_sq_thread() is weird. If multiple ctxs
> share one same poll thread, one ctx will put poll thread in TASK_INTERRUPTIBLE,
> but if other ctxs have work to do, we don't need to change task's stat at all.
> I think only if all ctxs don't have work to do, we can do it.
>    We use round-robin strategy to make multiple ctxs share one same poll thread,
> but there are various condition in __io_sq_thread(), which seems complicated and
> may affect round-robin strategy.
>    In io_sq_thread(), we always call io_sq_thread_drop_mm() when we complete a
> round of ctxs iteration, which maybe inefficient.
> 
> The second patch adds a IORING_SETUP_SQPOLL_PERCPU flag, for those rings which
> have SQPOLL enabled and are willing to be bound to one same cpu, hence share
> one same poll thread, add a capability that these rings can share one poll thread
> by specifying a new IORING_SETUP_SQPOLL_PERCPU flag. FIO tool can integrate this
> feature easily, so we can test multiple rings to share same poll thread easily.
> 
> Xiaoguang Wang (2):
>    io_uring: refactor io_sq_thread() handling
>    io_uring: support multiple rings to share same poll thread by
>      specifying same cpu
> 
>   fs/io_uring.c                 | 307 ++++++++++++++++++++--------------
>   include/uapi/linux/io_uring.h |   1 +
>   2 files changed, 181 insertions(+), 127 deletions(-)
>