Re: [RFC PATCH bpf-next] bpf: Introduce bpf_timer

[Cong Wang <xiyou.wangcong@gmail.com>]

On Sun, May 23, 2021 at 9:01 AM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Fri, May 21, 2021 at 2:37 PM Cong Wang <xiyou.wangcong@gmail.com> wrote:
> >
> > Hi, Alexei
> >
> > On Thu, May 20, 2021 at 11:52 PM Alexei Starovoitov
> > <alexei.starovoitov@gmail.com> wrote:
> > >
> > > From: Alexei Starovoitov <ast@kernel.org>
> >
> > Why do you intentionally keep people in the original discussion
> > out of your CC? Remember you are the one who objected the
> > idea by questioning its usefulness no matter how I hard I tried
> > to explain? I am glad you changed your mind, but it does not
> > mean you should forget to credit other people.
>
> I didn't change my mind and I still object to your stated
> _reasons_ for timers.

What is _your reason_ to introduce timers? Clearly you provide
absolutely nothing here. ;)


>
> > >
> > > Introduce 'struct bpf_timer' that can be embedded in most BPF map types
> > > and helpers to operate on it:
> > > long bpf_timer_init(struct bpf_timer *timer, void *callback, int flags)
> > > long bpf_timer_mod(struct bpf_timer *timer, u64 msecs)
> > > long bpf_timer_del(struct bpf_timer *timer)
> >
> > Like we discussed, this approach would make the timer harder
> > to be independent of other eBPF programs, which is a must-have
> > for both of our use cases (mine and Jamal's). Like you explained,
> > this requires at least another program array, a tail call, a mandatory
> > prog pinning to work.
>
> That is simply not true.

Which part is not true? The above is what I got from your explanation.

Thanks.