netdev - Re: [PATCH bpf-next v5 1/3] bpf: remove extra lock_sock for TCP_ZEROCOPY

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Date:   Fri, 8 Jan 2021 19:09:59 +0100
From:   Eric Dumazet <edumazet@...gle.com>
To:     Stanislav Fomichev <sdf@...gle.com>
Cc:     netdev <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>
Subject: Re: [PATCH bpf-next v5 1/3] bpf: remove extra lock_sock for TCP_ZEROCOPY_RECEIVE

On Fri, Jan 8, 2021 at 7:03 PM Stanislav Fomichev <sdf@...gle.com> wrote:
>
> Add custom implementation of getsockopt hook for TCP_ZEROCOPY_RECEIVE.
> We skip generic hooks for TCP_ZEROCOPY_RECEIVE and have a custom
> call in do_tcp_getsockopt using the on-stack data. This removes
> 3% overhead for locking/unlocking the socket.
>
> Without this patch:
>      3.38%     0.07%  tcp_mmap  [kernel.kallsyms]  [k] __cgroup_bpf_run_filter_getsockopt
>             |
>              --3.30%--__cgroup_bpf_run_filter_getsockopt
>                        |
>                         --0.81%--__kmalloc
>
> With the patch applied:
>      0.52%     0.12%  tcp_mmap  [kernel.kallsyms]  [k] __cgroup_bpf_run_filter_getsockopt_kern
>


OK but we are adding yet another indirect call.

Can you add a patch on top of it adding INDIRECT_CALL_INET() avoidance ?

Thanks.