Re: [RFC PATCH 6/8] preempt/dynamic: Provide preempt_schedule[_notrace]() static calls

From: Josh Poimboeuf
Date: Wed Jan 27 2021 - 14:04:38 EST


On Wed, Jan 27, 2021 at 01:00:07PM -0600, Josh Poimboeuf wrote:
> On Wed, Jan 27, 2021 at 07:44:01PM +0100, Peter Zijlstra wrote:
> > On Wed, Jan 27, 2021 at 10:33:08AM -0600, Josh Poimboeuf wrote:
> >
> > > What did you think about .static_call_tramp_key? I could whip up a
> > > patch later unless you beat me to it.
> >
> > Yeah, I'm not sure.. why duplicate information already present in
> > kallsyms?
>
> Well, but it's not exactly duplicating kallsyms. No need to store
> symbol names, just the pointer relationships. And kallsyms is
> presumably slow.
>
> > There's a fair number of features that already require KALLSYMS, I can't
> > really be bothered about adding one more (kprobes, function_tracer,
> > stack_tracer, ftrace_syscalls).
>
> Right, but I don't think they rely on KALLSYMS_ALL?

Scratch that, I forgot about your last hack. (That's what I get for
emailing during meetings.)

I mean - your patch is fine... let me just whip up the alternative and
we can compare.

--
Josh