From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout01.his.huawei.com (canpmsgout01.his.huawei.com [113.46.200.216]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A761C30C606; Thu, 24 Sep 2026 07:36:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.216 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790235373; cv=none; b=CtWX7GN4MTfzXA6KZdI9CWaiH9HStcqt65dA4jPAwPOfagtb1jeIXFnxfZYMaTIG8CKTPizvukoaGGFhy0cuU/Cw2kfx3JfrX1ZNdZVjCzkM/D4FaLWzswQBPyPqJmiA4dGh4a27L6RqJZcUlYzart+ppYd8nJageXBnwnB22pY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790235373; c=relaxed/simple; bh=QvBZ+KNbf1Sv2iCZKL5yKE7kDkDxi2J2crQOn0o0ii0=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nl1UT6O7upSKXcdXn7xJRE/1bis/xrN9JvWrpKGBA83LTusdDG9iHgEcriV4C7hJ9Khpoy1tqdVNtD7DV0Vt4GCf7oIuH7MXIzGCN7wjvc3vkWfEubZIXArfCqzoiLM8Oxmvn/WQ3xXCjq1rJoI8EpgIRpi2epZhWKxffBPHYxM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=ONhULbsY; arc=none smtp.client-ip=113.46.200.216 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="ONhULbsY" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=Eix0EmnHlcKPpRL88blWx7dbbcEZ9zSeXbIyhIkBRCg=; b=ONhULbsYqqPaOUYOa3JDqZ/SY1mBLmqXQhAASrJE77l3Rsek/yi+TtxaDEQcSnH8v8qzMV3RR ot0cD71MFbm5YZfOYMq7Hm3xIOlH1n4V9bMqj5y7GskAeWnQjBrUKzqiAW2EYw+HcTkR06rPwku Fdz82nUPyla8BslzzZM10rQ= Received: from mail.maildlp.com (unknown [172.19.163.104]) by canpmsgout01.his.huawei.com (SkyGuard) with ESMTPS id 4hr51V4K6kz1T4Km; 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-ClientProxiedBy: kwepems500001.china.huawei.com (7.221.188.70) To whupemk100010.china.huawei.com (7.152.184.41) 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