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Date:   Tue, 31 Oct 2023 12:53:48 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Daniel Borkmann <daniel@iogearbox.net>
Cc:     Peilin Ye <yepeilin.cs@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>,
        Yonghong Song <yonghong.song@linux.dev>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        Peilin Ye <peilin.ye@bytedance.com>, netdev@vger.kernel.org,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        Cong Wang <cong.wang@bytedance.com>,
        Jiang Wang <jiang.wang@bytedance.com>,
        Youlun Zhang <zhangyoulun@bytedance.com>
Subject: Re: [PATCH net] veth: Fix RX stats for bpf_redirect_peer() traffic
Message-ID: <20231031125348.70fc975e@kernel.org>
In-Reply-To: <94c88020-5282-c82b-8f88-a2d012444699@iogearbox.net>
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        <59be18ff-dabc-2a07-3d78-039461b0f3f7@iogearbox.net>
        <20231028231135.GA2236124@n191-129-154.byted.org>
        <94c88020-5282-c82b-8f88-a2d012444699@iogearbox.net>
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On Mon, 30 Oct 2023 15:19:26 +0100 Daniel Borkmann wrote:
> > Since I didn't want to update host-veth's TX counters.  If we
> > bpf_redirect_peer()ed a packet from NIC TC ingress to Pod-veth TC ingress,
> > I think it means we've bypassed host-veth TX?  
> 
> Yes. So the idea is to transition to tstats replace the location where
> we used to bump lstats with tstat's tx counter, and only the peer redirect
> would bump the rx counter.. then upon stats traversal we fold the latter into
> the rx stats which was populated by the opposite's tx counters. Makes sense.
> 
> OT: does cadvisor run inside the Pod to collect the device stats? Just
> curious how it gathers them.

Somewhat related - where does netkit count stats?

> >> Definitely no new stats ndo resp indirect call in fast path.  
> > 
> > Yeah, I think I'll put a comment saying that all devices that support
> > BPF_F_PEER must use tstats (or must use lstats), then.  
> 
> sgtm.

Is comment good enough? Can we try to do something more robust?
Move the allocation of stats into the core at registration based 
on some u8 assigned in the driver? (I haven't looked at the code TBH)