Re: softirq parameters

[Rusty Russell <rusty@rustcorp.com.au>]

On Sun, 04 Aug 2002 22:37:46 -0700 (PDT)
"David S. Miller" <davem@redhat.com> wrote:

>    From: george anzinger <george@mvista.com>
>    Date: Sun, 04 Aug 2002 10:38:23 -0700
> 
>    Matthew Wilcox wrote:
>    > what do you guys think about this patch?  nobody's using the data argument
>    > to the softirq routines, but most of the routines want to know which
>    > CPU they're running on.
>    
>    I would vote no on this.  While no one is currently using
>    the data argument, it would be _hard_ to replace it if it
>    were needed.  The cpu, on the other hand, is available
>    regardless of it being passed or not and thus does not
>    _need_ to be passed.
> 
> Furthermore, this is one of the most important hot paths in
> the entire kernel, any simplification and or improvement
> in code generated to implement these paths is desirable.
> 
> I fully supporty Matthew's change.

Partially agree.  Removing all args might be worthwhile.  But all these
softirqs use the "cpu" arg to access per-cpu data, which should be
changed to use the per_cpu_data mechanism anyway, which removes the
point of the arg.

Things haven't been changed over because I haven't pushed the per-cpu
interface changes (required for some archs 8() to Linus yet.  But you'll
want them so we can save space (you only need allocate per-cpu data for
cpus where cpu_possible(i) is true).

Clear?
Rusty.
-- 
   there are those who do and those who hang on and you don't see too
   many doers quoting their contemporaries.  -- Larry McVoy