[PATCH 0/3] drm: commit_work scheduling

[peterz at infradead.org]

On Mon, Sep 21, 2020 at 11:21:54AM +0200, Daniel Vetter wrote:

> So question to rt/worker folks: What's the best way to let userspace set
> the scheduling mode and priorities of things the kernel does on its
> behalf? Surely we're not the first ones where if userspace runs with some
> rt priority it'll starve out the kernel workers that it needs. Hardcoding
> something behind a subsystem ioctl (which just means every time userspace
> changes what it does, we need a new such flag or mode) can't be the right
> thing.
> 
> Peter, Tejun?

So regular workqueues do not support RT priorities, but you can set
their nice value somewhere in /sys.

The kthread_work stuff used in these patches result in a regular kthread
and as such the user interface for changing its scheduling class or
priority is that of any other 'random' task.