Re: [PATCH RFC v1 1/3] aio-poll: avoid unnecessary polling time computation

[JAEHOON KIM <jhkim@linux.ibm.com>]

On 2/17/2026 7:16 AM, Stefan Hajnoczi wrote:
> On Mon, Feb 16, 2026 at 02:47:27PM -0600, JAEHOON KIM wrote:
>> On 2/16/2026 9:21 AM, Stefan Hajnoczi wrote:
>>> On Tue, Jan 13, 2026 at 11:48:22AM -0600, Jaehoon Kim wrote:
>>>> Nodes are no longer added to poll_aio_handlers when adaptive polling is
>>>> disabled, preventing unnecessary try_poll_mode() calls. Additionally,
>>>> aio_poll() skips try_poll_mode() when timeout is 0.
>>>>
>>>> This avoids iterating over all nodes to compute max_ns unnecessarily
>>>> when polling is disabled or timeout is 0.
>>> Did you consider optimizing the case when polling is active and there is
>>> no way around calculating the polling time? Glib has ordered data
>>> structures that have lower operation costs than O(n).
>>>
>>> Stefan
>> If I understand correctly, while optimizing the data structure to be cheaper
>> than O(n) is one approach, I believe bypassing the function entirely
>> efficient
>> for cases where timeout=0 is frequently triggered.
>>
>> Since the result of the calculation is not used at all in these cases, it
>> seems
>> to more efficient to skip the function than to optimize calculation itself.
> Yes, skipping it when not needed makes sense and I'm in favor of it.
>
> I was thinking that, separately from this patch, the data structure
> might be worth optimizing since the value needs to be computed when
> polling is enabled.
>
> Stefan

That makes sense. I agree that when polling is enabled, optimizing the
data structure could help reduce the overhead of computing the value.
I'll take a closer look at potential improvements there.

Thanks,
Jaehoon