Re: [PATCH 8/8] RFC: use a TASK_FIFO kthread for read completion support

Gao Xiang
2026-04-15T06:05:08Z

On 2026/4/15 13:55, Christoph Hellwig wrote:
> On Tue, Apr 14, 2026 at 10:23:13AM +0800, Gao Xiang wrote:

...

>
>>> Tejun asked Sandeep if setting the workqueue thread priority to
>>> -19 through sysfs (i.e. making them higher priority than normal
>>> kernel threads) had the same effect on latency as using a dedicated
>>> per-cpu RT task thread. THere was no followup.
>>
>> I think the issue is that people are not already working on the
>> same topic:
>>
>> - Unlike large subsystems like XFS, people don't already work on
>> EROFS unless they have new requirements or urgent production
>> issues;
>>
>> - The original latency issue was already considered as "done" in
>> 2023, and I'm not sure if Sandeep could have the bandwidth to
>> pause his current work and test more setups according to this
>> ongoing discussion in 2026.
>
> Which unfortunately might explain the sad state of Android. You
> really need dedicated people around and help to improve core
> infrastructure, instead of adding random Kconfig choices.

Sigh, let's not regard it as a technical problem, and it's more
of a non-technical development resource issue among different
resource groups & vendors.

The detailed background is much much more complex than I could
write all down explicitly here, but at least I will try to
contact with Sandeep and more related people to test again
in 2026 if a cleaner approach can be worked out.

Thanks,
Gao Xiang