Re: [PATCH v5 2/6] mm/memcg: Disable threshold event handlers on PREEMPT_RT

Valentin Schneider
2023-03-01T18:23:19Z

On 26/02/22 21:41, Sebastian Andrzej Siewior wrote:
> During the integration of PREEMPT_RT support, the code flow around
> memcg_check_events() resulted in `twisted code'. Moving the code around
> and avoiding then would then lead to an additional local-irq-save
> section within memcg_check_events(). While looking better, it adds a
> local-irq-save section to code flow which is usually within an
> local-irq-off block on non-PREEMPT_RT configurations.
>

Hey, sorry for necro'ing a year-old thread - would you happen to remember
what the issues were with memcg_check_events()? I ran tests against
cgroupv1 using an eventfd on OOM with the usual debug arsenal and didn't
detect anything, I'm guessing it has to do with the IRQ-off region
memcg_check_events() is called from?

I want cgroupv1 to die as much as the next person, but in that specific
situation I kinda need cgroupv1 to behave somewhat sanely on RT with
threshold events :/

Cheers