Re: [PATCH RFC v1 3/3] qapi/iothread: introduce poll-weight parameter for aio-poll

[Markus Armbruster <armbru@redhat.com>]

Halil Pasic <pasic@linux.ibm.com> writes:

> On Thu, 15 Jan 2026 08:28:51 +0100
> Markus Armbruster <armbru@redhat.com> wrote:
>
>> I understand that you're mirroring how @poll-grow and @poll-shrink work,
>> but let's ignore that for a minute.
>> 
>> Compare four possible interfaces:
>> 
>> 1. Optional @poll-weight defaults to 2.  Values <= 0 are rejected.
>> 
>> 2. Optional @poll-weight defaults to 2.  Value 0 is replaced by the
>>    default value 2.  Values < 0 are rejected.
>> 
>> 3. Optional @poll-weight defaults to 0.  Values < 0 are rejected.  Value
>>    0 makes the system pick a value, namely 2.
>> 
>> 4. Optional @poll-weight defaults to 0.  Values < 0 are rejected.  Value
>>    0 makes the system pick a value.  It currently picks 2.
>> 
>> The difference between 3. and 4. is that 3. makes "system picks 2" part
>> of the contract, while 4. doesn't.
>> 
>> 1. is the simplest.  Is 2.'s additional complexity worthwhile?  3.'s?
>> 4.'s?
>
> Isn't there more options? Like

Yes :)

> 5. Optional @poll-weight defaults to system-default.  Value 0 is replaced
> by the system pick the system default value. Currently the system default
> value is 2. Values < 0 are rejected.
>
> That would mean:
> * current value inspectable
> * system default not part of the interface contract
> * interface offers a "please go back to value not user specified:
>   operation
>
> BTW I like your approach with explicitly listing and evaluating the
> options a lot!

Thanks!