[RFC] hung_task: task white-listing for hung tasks

[Aniruddha Banerjee <aniruddhab@nvidia.com>]

Hello,

In the current hung_task framework, there is no way to white-list tasks for which a higher hang time out might be acceptable and expected even:

Usecase: I want to keep a low hung_task timeout to catch more tasks which are hung-up. However, certain tasks (like sync, which flushes to a slow eMMC) may have a higher timeout.

Problem: There is no way to implement the aforementioned usecase without increasing the hang task timeout, which will reduce the effictiveness of the hung_task framework.

Solution:

1. Introduce a white-list of tasks that have a much higher timeout.
2. Create a simple sysfs interface with which it might be possible to dynamically add/remove any task in the white-list.

Please let me know what you think about the problem and the proposed solution?

Regards,
Aniruddha