Re: Comments on new user events ABI

[Steven Rostedt]

On Tue, 29 Mar 2022 09:25:52 -0700
Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote:

> Thanks for flagging.
> 
> Whoever added this user_bpf* stuff please remove it immediately.
> It was never reviewed by bpf maintainers.

Heh, now you know how the x86 maintainers feel ;-)

> 
> It's a hard Nack to add a bpf interface to user_events.

Agreed, I'm thinking of marking the entire thing as broken such that it can
be worked on a bit more without a total revert (but still remove the BPF
portion on your request).

Beau, I agree with Mathieu, I don't think it's a good idea to expose the
"ftrace/perf/etc" users. The only thing that the application needs is a bit
to say "call the write now". And let the work be done within the kernel.
I think a single bit may be better, that way you can have many more events
on a page, and since they do not get modified often, it will be in hot
cache and fast.

-- Steve