Re: [PATCH v6 0/6] ioctl()-based API to query VMAs from /proc//maps

Andrew Morton
2024-06-27T21:11:27Z

On Thu, 27 Jun 2024 13:50:22 -0700 Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:

> On Thu, Jun 27, 2024 at 12:59 PM Andrew Morton
> > Is it possible/sensible to make this feature Kconfigurable so that people who
> > don't need it can omit it?
>
> It's just a matter of #ifdef/#endif, so not hard, technically
> speaking. But I'm wondering what's the concern? This is mostly newly
> added code (except factoring out get_vma_name logic, which won't be
> #ifdef'ed anyways), so if no one is using this new API, then it should
> cause no issue.
>
> Generally speaking, I'd say if we don't *have to* add the Kconfig
> option, I'd prefer that. But if you feel strongly, it's not hard for
> me to do, of course.
>
> Or are you concerned with the vmlinux code size increase? It doesn't
> seem to be large enough to warrant a Kconfig, IMO (from
> bloat-o-meter):
>
> do_procmap_query - 1308 +1308
> get_vma_name - 283 +283
> procfs_procmap_ioctl - 47 +47
> show_map_vma 444 274 -170
>
> But again, do let me know if you insist.

Yes, I'm thinking about being nice to small systems ("make
tinyconfig"!). The kernel just gets bigger and bigger over time,
little bit by little bit.

It's a judgment call - if making it configurable is ugly and/or adds
maintenance overhead then no.