Re: r8169: disable ASPM during NAPI poll locking changes --> BUG: Invalid wait context --> PREEMPT_RT pain

From: Sebastian Andrzej Siewior
Date: Mon May 22 2023 - 04:06:12 EST


On 2023-05-21 16:27:10 [+0200], Mike Galbraith wrote:
> On Sun, 2023-05-21 at 08:03 +0200, Mike Galbraith wrote:
> > Greetings,
> >
> > The locks added to prep for $subject induce invalid context moaning due
> > to not being raw locks, but if I do that, the hold time does very bad
> > things to RT.
>
> The locks aren't really 160us horrible. The GPU was enabled (oops),
> nouveau then makes box horrible for RT (and graphics:). With GPU
> turned back off, the largest trace I saw was 77us, which jibes pretty
> well with new max of low to mid 50s without ftrace running, or up a tad
> over 20us for this now pretty old commodity i7 desktop box.

So you are saying it is all good?
I've been looking at the r8169 the other day and it seemed all good
since it was only scheduling workqueues and NAPI. But now I see this
mac_ocp_lock + config25_lock which are acquire in hardirq context but
can't. This needs to be taken care.

> -Mike

Sebastian