Re: [PATCH 2/4] generic-smp: remove kmalloc usage

Rusty Russell
2009-02-19T04:32:17Z

On Thursday 19 February 2009 02:35:35 Ingo Molnar wrote:
>
> * Rusty Russell <rusty@rustcorp.com.au> wrote:
>
> > On Tuesday 17 February 2009 20:13:59 Ingo Molnar wrote:
> > > We should not bend backwards trying to preserve that kmalloc()
> > > [and prove that it's safe and race-free] - i.e. the burden of
> > > proof is on the person insisting that it's needed, not on the
> > > person wanting to remove it.
> >
> > Respectfully disagree. The kmalloc has been there for a very long time,
> > and doing fine AFAICT.
>
> The kmalloc(GFP_ATOMIC) has been in kernel/smp.c for about half
> a year

Oops, yes.

So if we care about the kmalloc, why didn't we see benchmarks when we
switched from the x86 smp_call_function_mask to the generic one? Or did
I just miss them (there's nothing in the git commit).

Now, I think the current patch is quite neat and may not been benchmarks to
justify it, but it'd still be nice if it were faster, but noone seems to know.

Rusty.