Re: [PATCH 5/5] io_uring: leverage completion cache for poll requests

[Hao Xu <haoxu@linux.alibaba.com>]

在 2021/9/19 下午11:52, Hao Xu 写道:
> 在 2021/9/19 下午8:04, Pavel Begunkov 写道:
>> On 9/18/21 7:11 AM, Hao Xu wrote:
>>> 在 2021/9/18 上午4:39, Pavel Begunkov 写道:
>>>> On 9/17/21 8:38 PM, Hao Xu wrote:
>>>>> Leverage completion cache to handle completions of poll requests in a
>>>>> batch.
>>>>> Good thing is we save compl_nr - 1 completion_lock and
>>>>> io_cqring_ev_posted.
>>>>> Bad thing is compl_nr extra ifs in flush_completion.
>>>>
>>>> It does something really wrong breaking all abstractions, we can't go
>>>> with this. Can we have one of those below?
>>>> - __io_req_complete(issue_flags), forwarding issue_flags from above
>>>> - or maybe io_req_task_complete(), if we're in tw
>>> Make sense. we may need to remove io_clean_op logic in
>>
>>> io_req_complete_state(), multishot reqs shouldn't do it, and it's ok for
>>> normal reqs since we do it later in __io_submit_flush_completions->
>>> io_req_free_batch->io_dismantle_req->io_clean_op, correct me if I'm
>>> wrong.
>>
>> req->compl.cflags is in the first 64B, i.e. aliased with req->rw and
>> others. We need to clean everything left in there before using the
>> space, that's what io_clean_op() there is for
> True, and that's why we souldn't do it for multishot reqs, since they
> are not completed yet, and we won't reuse the req resource until its
> final completion.
I see what you are saying now..yes, we shouldn't remove that
io_clean_op there.
>>