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Date: Thu, 18 Jan 2024 17:50:06 +0100
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Jakub Kicinski <kuba@kernel.org>
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Subject: Re: [PATCH net-next 15/24] net: Use nested-BH locking for XDP
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On 2024-01-18 08:38:12 [-0800], Jakub Kicinski wrote:
> > If this is the per-CPU BH lock (which I want to remove) then it will
> > continue until all softirqs complete.
>=20
> So there's no way for a process to know on RT that someone with higher
> prio is waiting for it to release its locks? :(

You could add a function to check if your current priority is inherited
=66rom someone else and if so start dropping the locks you think are
responsible for it.
I made a PoC that appears to work for timer_list timer which is one of
the softirqs. This made me realise that I need in more spots and I am
doing it for the wrong reasons=E2=80=A6

Sebastian