Re: [PATCH 03/10] smp,cpumask: introduce on_each_cpu_cond_mask

From: Linus Torvalds
Date: Sun Jul 29 2018 - 15:57:00 EST


On Sun, Jul 29, 2018 at 11:55 AM Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> > On Jul 29, 2018, at 10:51 AM, Rik van Riel <riel@xxxxxxxxxxx> wrote:
> >
> > This seems to result in systems with ->has_wbinvd_exit
> > only calling wbinvd_ipi on OTHER CPUs, and not on the
> > CPU where the guest exited with wbinvd?
> >
> > This seems unintended.
> >
> > I guess looking into on_each_cpu_mask might be a little
> > higher priority than waiting until the next Outreachy
> > season :)
>
> The right approach might be a tree wise rename from smp_call_... to on_other_cpus_mask() it similar. The current naming and semantics are extremely confusing.

Ugh.

Renaming might be worth it, but at least one issue is that we are
simply not very consistent.

For example. smp_call_function_many() does indeed explicitly ignore
the current CPU.

But smp_call_function_any() (one "m" less) does _not_ ignore the
current CPU, and in fact prefers it.

So it's not that smp_call_... should *generally* be renamed. Only some
of the cases might be worth renaming.

And just a "rename and forget" isn't really great. As Rik's example
shows, existing users should be checked too..

Linus