Re: [PATCH] android: binder: Disable preemption while holding the global binder lock

Peter Zijlstra
2016-09-14T13:38:33Z

On Wed, Sep 14, 2016 at 09:10:01AM +0200, Peter Zijlstra wrote:
> On Tue, Sep 13, 2016 at 12:53:27PM -0700, Arve Hjønnevåg wrote:

> > Most of the tasks here are not RR/FIFO/DL tasks. I don't see anything
> > in the rtmutex code or documentation that indicates that they don't
> > work for normal tasks. From what I can tell the priority gets boosted
> > in every case. This may not work as well for CFS tasks as for realtime
> > tasks, but it should at least help when there is a large priority
> > difference.
>
> It does something (it used to explicitly ignore OTHER) but its not
> something well defined or usable.

I looked again, and while it updates the ->prio field for OTHER tasks,
that does not seem to cause a change to the actual weight field (which
is derived from ->static_prio).

So it really should not do anything.. as I remebered it.