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From: Martin KaFai Lau <kafai@fb.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: "Toke Høiland-Jørgensen" <toke@redhat.com>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"Linux Kernel Network Developers" <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>, "Cong Wang" <cong.wang@bytedance.com>,
	"Jamal Hadi Salim" <jhs@mojatatu.com>,
	"Jiri Pirko" <jiri@resnulli.us>
Subject: Re: [RFC Patch net-next] net_sched: introduce eBPF based Qdisc
Date: Thu, 16 Sep 2021 21:19:03 -0700	[thread overview]
Message-ID: <20210917041903.yuepvbvajtheuvct@kafai-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <CAM_iQpUjJ+goqoFX+vPUXbcvt3oDga2UgA-MKMXJh9iYY8j_6g@mail.gmail.com>

On Fri, Sep 03, 2021 at 06:09:46PM -0700, Cong Wang wrote:
> On Wed, Sep 1, 2021 at 10:45 AM Martin KaFai Lau <kafai@fb.com> wrote:
> > _if_ it is using as a qdisc object/interface,
> > the patch "looks" easier because it obscures some of the ops/interface
> > from the bpf user.  The user will eventually ask for more flexibility
> > and then an on-par interface as the kernel's qdisc.  If there are some
> > common 'ops', the common bpf code can be shared as a library in userspace
> > or there is also kfunc call to call into the kernel implementation.
> > For existing kernel qdisc author,  it will be easier to use the same
> > interface also.
> 
> Thanks for showing the advantages of a kernel module. And no, we
> are not writing kernel modules in eBPF.
The line is very blurry between a bpf_prog and kernel module,
especially with the advancement of bpf, btf, and CO-RE.

Both bpf_prog.o (struct_ops or not) and some_native_kern_mod.ko are attaching
to some kernel hooks to be called.  If writing bpf and attaching it to a hook
does not work for you, bpf does not fit your case.

> And kfunc call really sucks, it does not even guarantee a stable ABI, it
> is a serious mistake you made for eBPF.
Not ture.  It depends on what is allowed to be called by bpf.
Needless to say I cannot agree with the "sucks" description.

This kind of dismissive discussion is worse than unproductive
and not the best way to use the mailing list time.

  reply	other threads:[~2021-09-17  4:19 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-21  1:02 [RFC Patch net-next] net_sched: introduce eBPF based Qdisc Cong Wang
2021-08-24 23:47 ` Martin KaFai Lau
2021-09-01  4:39   ` Cong Wang
2021-09-01  5:45     ` John Fastabend
2021-09-01 10:42       ` Toke Høiland-Jørgensen
2021-09-01 17:45         ` Martin KaFai Lau
2021-09-01 18:03           ` Alexei Starovoitov
2021-09-02 16:57           ` Toke Høiland-Jørgensen
2021-09-02 20:40             ` John Fastabend
2021-09-02 22:27               ` Toke Høiland-Jørgensen
2021-09-02 23:35                 ` Martin KaFai Lau
2021-09-03 14:44                   ` Toke Høiland-Jørgensen
2021-09-03 15:33                     ` Jamal Hadi Salim
2021-09-10  6:55                     ` Martin KaFai Lau
2021-09-10 11:31                       ` Toke Høiland-Jørgensen
2021-09-04  1:09           ` Cong Wang
2021-09-17  4:19             ` Martin KaFai Lau [this message]
2021-09-04  1:30         ` Cong Wang
2021-09-06 11:45           ` Toke Høiland-Jørgensen
2021-09-04  1:05       ` Cong Wang

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