On Mon, Jun 13, 2022 at 8:27 PM Sebastian Andrzej Siewior
<bigeasy@xxxxxxxxxxxxx> wrote:
>
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>
> PREEMPT_RT preempts softirqs and the current implementation avoids
> do_softirq_own_stack() and only uses __do_softirq().
>
> Disable the unused softirqs stacks on PREEMPT_RT to safe some memory and
> ensure that do_softirq_own_stack() is not used which is not expected.
>
> [bigeasy: commit description.]
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
It's probably best to keep this together with the corresponding architecture
specific changes. I was a bit worried about bisection at first, but
then realized
that this is not a problem for mainline since ARCH_SUPPORTS_RT is not
yet enabled on any architecture.
How are softirqs called on preempt_rt? Does this result in higher stack usage
for the normal task stacks again, or are they run in separate threads anyway?
Arnd
