On Tue, Jun 14, 2022 at 9:11 AM Sebastian Andrzej Siewior
<bigeasy@xxxxxxxxxxxxx> wrote:
>
> On 2022-06-13 23:13:49 [+0200], Arnd Bergmann wrote:
> > 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.
>
> So where do I put this patch to? If I remember correctly then arm64 is
> using this. ARM has its own thing and x86 has this change already.
I don't see HAVE_SOFTIRQ_ON_OWN_STACK for arm, parisc, powerpc,
s390, sh, sparc and x86, but not arm64. I would suggest having a single
patch that does the same change across all architectures that don't already do
this, and then merging it either through tip or through my asm-generic tree.
> - ksoftirqd thread.
> - in the force-threaded interrupt after the main handler.
> - any time after bh-counter hits zero due local_bh_enable().
>
> The last one will cause higher task stacks.
Does this mean it only happens when a softirq gets raised from task context
(which would be predictable), or also at an arbitrary time if it gets raised
by a non-threaded hardirq or IPI?
Arnd
