From: Martin KaFai Lau <martin.lau@linux.dev>
To: Kuniyuki Iwashima <kuniyu@google.com>,
Shakeel Butt <shakeel.butt@linux.dev>,
Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Stanislav Fomichev <sdf@fomichev.me>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@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 v8 bpf-next/net 2/6] net-memcg: Allow decoupling memcg from global protocol memory accounting.
Date: Wed, 17 Sep 2025 12:18:28 -0700 [thread overview]
Message-ID: <dcc22c04-94fb-4e1c-a69f-b033078867c7@linux.dev> (raw)
In-Reply-To: <20250910192057.1045711-3-kuniyu@google.com>
On 9/10/25 12:19 PM, Kuniyuki Iwashima wrote:
> Some protocols (e.g., TCP, UDP) implement memory accounting for socket
> buffers and charge memory to per-protocol global counters pointed to by
> sk->sk_proto->memory_allocated.
>
> If a socket has sk->sk_memcg, this memory is also charged to memcg as
> "sock" in memory.stat.
>
> We do not need to pay costs for two orthogonal memory accounting
> mechanisms. A microbenchmark result is in the subsequent bpf patch.
>
> Let's decouple sockets under memcg from the global per-protocol memory
> accounting if mem_cgroup_sk_exclusive() returns true.
>
> Note that this does NOT disable memcg, but rather the per-protocol one.
The bpf side changes look reasonable. I believe the commit message in v8 has
clarified the reason and its behavior. memcg reviewers, please take a look.
next prev parent reply other threads:[~2025-09-17 19:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-10 19:19 [PATCH v8 bpf-next/net 0/6] bpf: Allow decoupling memcg from sk->sk_prot->memory_allocated Kuniyuki Iwashima
2025-09-10 19:19 ` [PATCH v8 bpf-next/net 1/6] tcp: Save lock_sock() for memcg in inet_csk_accept() Kuniyuki Iwashima
2025-09-17 6:37 ` kernel test robot
2025-09-17 6:37 ` [LTP] " kernel test robot
2025-09-17 7:03 ` Kuniyuki Iwashima
2025-09-17 7:03 ` [LTP] " Kuniyuki Iwashima via ltp
2025-09-10 19:19 ` [PATCH v8 bpf-next/net 2/6] net-memcg: Allow decoupling memcg from global protocol memory accounting Kuniyuki Iwashima
2025-09-17 19:18 ` Martin KaFai Lau [this message]
2025-09-10 19:19 ` [PATCH v8 bpf-next/net 3/6] net-memcg: Introduce net.core.memcg_exclusive sysctl Kuniyuki Iwashima
2025-09-10 19:19 ` [PATCH v8 bpf-next/net 4/6] bpf: Support bpf_setsockopt() for BPF_CGROUP_INET_SOCK_CREATE Kuniyuki Iwashima
2025-09-10 19:19 ` [PATCH v8 bpf-next/net 5/6] bpf: Introduce SK_BPF_MEMCG_FLAGS and SK_BPF_MEMCG_EXCLUSIVE Kuniyuki Iwashima
2025-09-10 19:19 ` [PATCH v8 bpf-next/net 6/6] selftest: bpf: Add test for SK_MEMCG_EXCLUSIVE Kuniyuki Iwashima
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