Re: [PATCH bpf-next 00/13] Introduce BPF STRUCT_OPS

[Eric Dumazet <eric.dumazet@gmail.com>]

On 12/13/19 4:47 PM, Martin KaFai Lau wrote:
> This series introduces BPF STRUCT_OPS.  It is an infra to allow
> implementing some specific kernel's function pointers in BPF.
> The first use case included in this series is to implement
> TCP congestion control algorithm in BPF  (i.e. implement
> struct tcp_congestion_ops in BPF).
> 
> There has been attempt to move the TCP CC to the user space
> (e.g. CCP in TCP).   The common arguments are faster turn around,
> get away from long-tail kernel versions in production...etc,
> which are legit points.
> 
> BPF has been the continuous effort to join both kernel and
> userspace upsides together (e.g. XDP to gain the performance
> advantage without bypassing the kernel).  The recent BPF
> advancements (in particular BTF-aware verifier, BPF trampoline,
> BPF CO-RE...) made implementing kernel struct ops (e.g. tcp cc)
> possible in BPF.
> 
> The idea is to allow implementing tcp_congestion_ops in bpf.
> It allows a faster turnaround for testing algorithm in the
> production while leveraging the existing (and continue growing) BPF
> feature/framework instead of building one specifically for
> userspace TCP CC.
>

This is awesome work Martin !