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Thu, 24 Sep 2026 15:24:14 +0800 (CST) Received: from whupemk100010.china.huawei.com (unknown [7.152.184.41]) by mail.maildlp.com (Postfix) with ESMTPS id 60CFB4058C; Thu, 24 Sep 2026 15:36:07 +0800 (CST) Received: from octopus.huawei.com (10.67.174.191) by whupemk100010.china.huawei.com (7.152.184.41) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.45; Thu, 24 Sep 2026 15:36:05 +0800 From: Cai Xinchen To: , , , , , , , , , , , , , , , , , , , , CC: , , , , , , , , Subject: [PATCH RFC -next 2/5] tcp: sync memcg budget on protocol buffer updates Date: Thu, 24 Sep 2026 16:02:16 +0800 Message-ID: <20260924080219.1036588-3-caixinchen1@huawei.com> X-Mailer: git-send-email 2.18.0.huawei.25 In-Reply-To: <20260924080219.1036588-1-caixinchen1@huawei.com> References: <20260924080219.1036588-1-caixinchen1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.67.174.191] X-ClientProxiedBy: kwepems500001.china.huawei.com (7.221.188.70) To whupemk100010.china.huawei.com (7.152.184.41) X-Rspam-User: X-Stat-Signature: e3a53o6f7un3gywtcpxrhxfq1475o5xt X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 55143140007 X-HE-Tag: 1790235373-208225 X-HE-Meta: U2FsdGVkX1+jLH7KzHKWNvYlNjEGEdx08xH3L6W+jqyMxf3AHn4MTGWHes7w6Axcnh0Gis+to+zWWI9LBCHl2sfbjGpykrjsyIUiN14Gr9eC6k7ZXv1gb+cw0y0/RdfWQXjvvW0zQcuIsAA7P2L1PdG/tRMdiTDPfvm7Qi1F5PigScIAaCjJFOggGGdZMYWPeDzkIpoXHUbhCqIvhvjJADMjRdjIkM11CldwQ2e80H9Lvja9CcBiRZuc4qeHf3YGnOH0sg82oZC0KgILWafdCWP6ikEAVVX62lZTgCFI0neadL7AW0OZIUhFtswAWlYD6diOqBRtkL1iRiBuRf+czfEqvKr3aXO93n4Ir1FVBSMSwIxP/rWPYjmHu1/68q0YlNf+ZcaE17Pi6k7SD5cvLGX3XD15aBmRi2cNughXR2UozHeeBvZ9R8kwotVoEmLCeMNmzfLiV3Ut/dnd+FclwOH5bN8fVZhypWz/TTA97HrCh9PrVJHqv1WtiyLK84SoHPQmruxnQGeEKQq6id2IeOn92+6MJZOMIgwxsZyeRdpQkpTbVEgflhHuKC2pSysEMnEcHwdP9HrFRvcA/QeiI8ysry0crjO7n60nvibWify2TcPSggc0Y9BIcXEKCwPgD6sJcgaq5jRmZEpE6nPebMmnVSXoi+1l0ORt0c4CfGdHX/92BeKWHTXoIDwSDtaFk+7gL0oZoUbPkfAxVr40S7kPml8WK5F8k1NGZqsZLGqhq7NO80FdJQkXrtDKeXSICrjIcW1xeiJlnCkgEuDZZQqnS2AACMFQTSe0/EsUqsxqvYgR8OzcdTolrVzCz9Brz3jKm/yaRQQQKz6M3vN32v1Vb3eKZ3nC3OYTWTI0Et4l5tK7a2k+0WGVeDUyb/SWAisgPk4e83E6yJEdpuo8AgL+miUmXVp4WqXCCXvNuoHU7Fh/+S27qySvt1Aj8j8Ov/01pLwVHCjwXN0+rO4 W7zNaSPa 4QoFaR0Na+wYU6iKeuKmxeQXzFPbu9580tsu/vxoqCTk3hH7/q+BS7A0sWCZ7m47JPB+YYTTJfIZlUV+pDu0An/jMQYj/ZrItUu3/c0AEIei5kwl8oOxGExqNlQ1WdOWerZpiHRRnb3Q6qm9s/kGetj5mB3iyfT1d7r96U9DieJNrWxBFaruoSf0dcOSJmWT8XZ7pOZreKRilRXh1QOcBQ1VBubIZjVMfbcM+mQUhyKQr7Bb/AlbfLLU/W8TRy+wYTAPfdEz38Lpl4YvR9tuCnuSH/27jrkBoo8x2+RkKyD4hOunJvpx4j5/r/QAsDBfBH4Klf/dvAlpF7fs= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: TCP rewrites the socket buffers after sock_init_data() already charged the generic defaults, and keeps rewriting them during autotuning: - tcp_init_sock() overrides sk_sndbuf/sk_rcvbuf with the per-net tcp_wmem/tcp_rmem sysctl defaults, - tcp_set_rcvlowat() raises sk_rcvbuf from the requested rcv window, - tcp_sndbuf_expand(), tcp_clamp_window() and tcp_rcvbuf_grow() grow the buffers during autotuning, and - tcp_should_expand_sndbuf() caps sk_sndbuf under memory pressure. Sync the memcg budget tracker with sk_memcg_budget_sync() at each of these writes so the charged amount follows the actual budget: growth is charged to the memcg, shrink is refunded. Assisted-by: opencode:glm-5.3 Signed-off-by: Cai Xinchen --- net/ipv4/tcp.c | 5 +++++ net/ipv4/tcp_input.c | 10 ++++++++-- 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 3c9e1a88a6bd..0d2a39672aa0 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -471,6 +471,10 @@ void tcp_init_sock(struct sock *sk) WRITE_ONCE(sk->sk_sndbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[1])); WRITE_ONCE(sk->sk_rcvbuf, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_rmem[1])); + /* The default buffers grew from the generic sock_init_data() + * values: charge the difference to the memcg. + */ + sk_memcg_budget_sync(sk, gfp_memcg_charge()); tcp_scaling_ratio_init(sk); set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags); @@ -1847,6 +1851,7 @@ int tcp_set_rcvlowat(struct sock *sk, int val) space = tcp_space_from_win(sk, val); if (space > sk->sk_rcvbuf) { WRITE_ONCE(sk->sk_rcvbuf, space); + sk_memcg_budget_sync(sk, gfp_memcg_charge()); if (tp->window_clamp && tp->window_clamp < val) WRITE_ONCE(tp->window_clamp, val); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 0f60a1dbf927..8abec8ebf916 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -629,9 +629,11 @@ static void tcp_sndbuf_expand(struct sock *sk) sndmem = ca_ops->sndbuf_expand ? ca_ops->sndbuf_expand(sk) : 2; sndmem *= nr_segs * per_mss; - if (sk->sk_sndbuf < sndmem) + if (sk->sk_sndbuf < sndmem) { WRITE_ONCE(sk->sk_sndbuf, min(sndmem, READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_wmem[2]))); + sk_memcg_budget_sync(sk, gfp_memcg_charge()); + } } /* 2. Tuning advertised window (window_clamp, rcv_ssthresh) @@ -791,6 +793,7 @@ static void tcp_clamp_window(struct sock *sk) sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)) { WRITE_ONCE(sk->sk_rcvbuf, min(atomic_read(&sk->sk_rmem_alloc), rmem2)); + sk_memcg_budget_sync(sk, gfp_memcg_charge()); } if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) tp->rcv_ssthresh = min(tp->window_clamp, 2U * tp->advmss); @@ -948,6 +951,7 @@ void tcp_rcvbuf_grow(struct sock *sk, u32 newval) rcvbuf = min_t(u32, tcp_space_from_win(sk, rcvwin), cap); if (rcvbuf > sk->sk_rcvbuf) { WRITE_ONCE(sk->sk_rcvbuf, rcvbuf); + sk_memcg_budget_sync(sk, gfp_memcg_charge()); /* Make the window clamp follow along. */ WRITE_ONCE(tp->window_clamp, tcp_win_from_space(sk, rcvbuf)); @@ -6055,8 +6059,10 @@ static bool tcp_should_expand_sndbuf(struct sock *sk) * it never goes below SOCK_MIN_SNDBUF. * See sk_stream_moderate_sndbuf() for more details. */ - if (unused_mem > SOCK_MIN_SNDBUF) + if (unused_mem > SOCK_MIN_SNDBUF) { WRITE_ONCE(sk->sk_sndbuf, unused_mem); + sk_memcg_budget_sync(sk, gfp_memcg_charge()); + } return false; } -- 2.18.0.huawei.25