Re: [PATCH 06/12] uprobes: add batch uprobe register/unregister APIs

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Mon, 1 Jul 2024 18:34:55 -0700
Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:

> > > How about this? I'll keep the existing get_uprobe_consumer(idx, ctx)
> > > contract, which works for the only user right now, BPF multi-uprobes.
> > > When it's time to add another consumer that works with a linked list,
> > > we can add another more complicated contract that would do
> > > iterator-style callbacks. This would be used by linked list users, and
> > > we can transparently implement existing uprobe_register_batch()
> > > contract on top of if by implementing a trivial iterator wrapper on
> > > top of get_uprobe_consumer(idx, ctx) approach.
> >
> > Agreed, anyway as far as it uses an array of uprobe_consumer, it works.
> > When we need to register list of the structure, we may be possible to
> > allocate an array or introduce new function.
> >
> 
> Cool, glad we agree. What you propose above with start + next + ctx
> seems like a way forward if we need this.
> 
> BTW, is this (batched register/unregister APIs) something you'd like
> to use from the tracefs-based (or whatever it's called, I mean non-BPF
> ones) uprobes as well? Or there is just no way to even specify a batch
> of uprobes? Just curious if you had any plans for this.

No, because current tracefs dynamic event interface is not designed for
batched registration. I think we can expand it to pass wildcard symbols
(for kprobe and fprobe) or list of addresses (for uprobes) for uprobe.
Um, that maybe another good idea.

Thank you!

-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>