From: Eric Dumazet <eric.dumazet@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: brakmo <brakmo@fb.com>, netdev <netdev@vger.kernel.org>,
Martin Lau <kafai@fb.com>, Alexei Starovoitov <ast@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 0/7] bpf: Propagate cn to TCP
Date: Mon, 25 Mar 2019 01:48:27 -0700 [thread overview]
Message-ID: <27e91d11-b454-924d-58ab-a68a0aade906@gmail.com> (raw)
In-Reply-To: <5aec97f1-545a-f898-fdd9-c5821d5c6e39@gmail.com>
On 03/25/2019 01:33 AM, Eric Dumazet wrote:
>
>
> On 03/24/2019 09:19 AM, Alexei Starovoitov wrote:
>> Cover letter also explains why bpf_skb_ecn_set_ce is not enough.
>> Please realize that existing qdiscs already doing this.
>> The patchset allows bpf-cgroup to do the same.
>
> Not the same thing I am afraid.
To be clear Alexei :
Existing qdisc set CE mark on a packet, exactly like a router would do.
Simple and universal.
This can be stacked, and done far away from the sender.
We do not _call_ back local TCP to propagate cn.
We simply rely on the fact that incoming ACK will carry the needed information,
and TCP stack already handles the case just fine.
Larry cover letter does not really explain why we need to handle a corner case
(local drops) with such intrusive changes.
TCP Small Queues already should make sure local drops are non existent.
next prev parent reply other threads:[~2019-03-25 8:48 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-23 8:05 [PATCH bpf-next 0/7] bpf: Propagate cn to TCP brakmo
2019-03-23 8:05 ` [PATCH bpf-next 1/7] bpf: Create BPF_PROG_CGROUP_INET_EGRESS_RUN_ARRAY brakmo
2019-03-23 8:05 ` [PATCH bpf-next 2/7] bpf: cgroup inet skb programs can return 0 to 3 brakmo
2019-03-23 8:05 ` [PATCH bpf-next 3/7] bpf: Update __cgroup_bpf_run_filter_skb with cn brakmo
2019-03-23 8:05 ` [PATCH bpf-next 4/7] bpf: Update BPF_CGROUP_RUN_PROG_INET_EGRESS calls brakmo
2019-03-23 8:05 ` [PATCH bpf-next 5/7] bpf: sysctl for probe_on_drop brakmo
2019-03-23 8:05 ` [PATCH bpf-next 6/7] bpf: Add cn support to hbm_out_kern.c brakmo
2019-03-23 8:05 ` [PATCH bpf-next 7/7] bpf: Add more stats to HBM brakmo
2019-03-23 9:12 ` [PATCH bpf-next 0/7] bpf: Propagate cn to TCP Eric Dumazet
2019-03-23 15:41 ` Alexei Starovoitov
2019-03-24 5:36 ` Eric Dumazet
2019-03-24 16:19 ` Alexei Starovoitov
2019-03-25 8:33 ` Eric Dumazet
2019-03-25 8:48 ` Eric Dumazet [this message]
2019-03-26 4:27 ` Alexei Starovoitov
2019-03-26 8:06 ` Eric Dumazet
2019-03-26 15:07 ` Alexei Starovoitov
2019-03-26 15:43 ` Eric Dumazet
2019-03-26 17:01 ` Alexei Starovoitov
2019-03-26 18:07 ` Eric Dumazet
2019-03-26 8:13 ` Eric Dumazet
2019-03-24 5:48 ` Eric Dumazet
2019-03-24 1:14 ` Lawrence Brakmo
2019-03-24 5:58 ` Eric Dumazet
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