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Miller" , Eric Dumazet , Paolo Abeni , Khalid Manaa , Ben Ben-Ishay , Simon Horman , netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260817181618.2786456-1-cosmosocket@gmail.com> <20260819160303.4be803c5@kernel.org> Content-Language: en-US From: Dragos Tatulea In-Reply-To: <20260819160303.4be803c5@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: FR2P281CA0110.DEUP281.PROD.OUTLOOK.COM (2603:10a6:d10:9c::20) To CH3PR12MB8728.namprd12.prod.outlook.com (2603:10b6:610:171::12) Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR12MB8728:EE_|CH3PR12MB8910:EE_ X-MS-Office365-Filtering-Correlation-Id: 6cdcf1c0-d3da-47f4-3197-08defebee5d7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|7416014|366016|1800799024|376014|4143699003|56012099006|10067099003|11063799006|18002099003|22082099003; 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The L3/L4 headers that >> header-data split placed in the linear area are not accounted for, and >> the limit is inclusive of GRO_LEGACY_MAX_SIZE. > > This regresses both ipv4-large-rem and ipv6-large-rem on CX7 > > # # Exception| STDERR: Expected {64896 600 600 }, Total 3 packets > # # Exception| Received {60840 [!=64896]4656 [!=600]600 }, Total 3 packets. > > we could have fit another MSS into the aggregate, easily. Uh, yes... thanks for the early warning. I've wanted to improve this function before but had a mental blockage on the page size difference. Looking at it with fresh eyes I think we can make it clearer: +static bool mlx5e_hw_gro_skb_has_enough_space(struct sk_buff *skb, + u16 data_bcnt, u32 page_size) +{ + int nr_frags = skb_shinfo(skb)->nr_frags; + + if (nr_frags + DIV_ROUND_UP(data_bcnt, page_size) > MAX_SKB_FRAGS) + return false; + + return skb->len + data_bcnt <= GRO_LEGACY_MAX_SIZE; +} Maybe we can squeeze more out of the last frag page, but one too many extra checks would need to be added because SHAMPO might have moved on to a new page. Thanks, Dragos