linux-kernel - Re: r8169: disable ASPM during NAPI poll locking changes --> BUG: Invalid wait context --> PREEMPT

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Date:   Sun, 21 May 2023 16:27:10 +0200
From:   Mike Galbraith <efault@....de>
To:     Heiner Kallweit <hkallweit1@...il.com>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: Re: r8169: disable ASPM during NAPI poll locking changes --> BUG:
 Invalid wait context --> PREEMPT_RT pain

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.

	-Mike