From: Johannes Weiner <hannes@cmpxchg.org>
To: Kuniyuki Iwashima <kuniyu@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
Stanislav Fomichev <sdf@fomichev.me>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Neal Cardwell <ncardwell@google.com>,
Willem de Bruijn <willemb@google.com>,
Mina Almasry <almasrymina@google.com>,
Kuniyuki Iwashima <kuni1840@gmail.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH v5 bpf-next/net 4/5] net-memcg: Allow decoupling memcg from global protocol memory accounting.
Date: Thu, 4 Sep 2025 07:34:56 +0100 [thread overview]
Message-ID: <20250904063456.GB2144@cmpxchg.org> (raw)
In-Reply-To: <20250903190238.2511885-5-kuniyu@google.com>
On Wed, Sep 03, 2025 at 07:02:03PM +0000, Kuniyuki Iwashima wrote:
> If all workloads were guaranteed to be controlled under memcg, the issue
> could be worked around by setting tcp_mem[0~2] to UINT_MAX.
>
> In reality, this assumption does not always hold, and processes not
> controlled by memcg lose the seatbelt and can consume memory up to
> the global limit, becoming noisy neighbour.
It's been repeatedly pointed out to you that this container
configuration is not, and cannot be, supported. Processes not
controlled by memcg have many avenues to become noisy neighbors in a
multi-tenant system.
So my NAK still applies. Please carry this forward in all future patch
submissions even if your implementation changes.
next prev parent reply other threads:[~2025-09-04 6:34 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-03 19:01 [PATCH v5 bpf-next/net 0/5] bpf: Allow decoupling memcg from sk->sk_prot->memory_allocated Kuniyuki Iwashima
2025-09-03 19:02 ` [PATCH v5 bpf-next/net 1/5] tcp: Save lock_sock() for memcg in inet_csk_accept() Kuniyuki Iwashima
2025-09-03 19:02 ` [PATCH v5 bpf-next/net 2/5] bpf: Support bpf_setsockopt() for BPF_CGROUP_INET_SOCK_CREATE Kuniyuki Iwashima
2025-09-03 19:02 ` [PATCH v5 bpf-next/net 3/5] bpf: Introduce SK_BPF_MEMCG_FLAGS and SK_BPF_MEMCG_SOCK_ISOLATED Kuniyuki Iwashima
2025-09-03 19:02 ` [PATCH v5 bpf-next/net 4/5] net-memcg: Allow decoupling memcg from global protocol memory accounting Kuniyuki Iwashima
2025-09-04 6:34 ` Johannes Weiner [this message]
2025-09-04 20:21 ` Kuniyuki Iwashima
2025-09-05 21:25 ` Shakeel Butt
2025-09-05 21:56 ` Kuniyuki Iwashima
2025-09-03 19:02 ` [PATCH v5 bpf-next/net 5/5] selftest: bpf: Add test for SK_BPF_MEMCG_SOCK_ISOLATED Kuniyuki Iwashima
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