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Thu, 5 Mar 2026 11:48:15 +0000 Date: Thu, 5 Mar 2026 12:48:02 +0100 From: Larysa Zaremba To: Jakub Kicinski CC: , Claudiu Manoil , "Vladimir Oltean" , Wei Fang , Clark Wang , Andrew Lunn , "David S. Miller" , Eric Dumazet , "Paolo Abeni" , Tony Nguyen , "Przemek Kitszel" , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , "Stanislav Fomichev" , Andrii Nakryiko , "Martin KaFai Lau" , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Simon Horman , Shuah Khan , Alexander Lobakin , "Maciej Fijalkowski" , "Bastien Curutchet (eBPF Foundation)" , Tushar Vyavahare , Jason Xing , Ricardo =?iso-8859-1?Q?B=2E_Marli=E8re?= , Eelco Chaudron , Lorenzo Bianconi , "Toke Hoiland-Jorgensen" , , , , , , Aleksandr Loktionov , Dragos Tatulea Subject: Re: [PATCH bpf v4 0/9] Address XDP frags having negative tailroom Message-ID: References: <20260302161723.858616-1-larysa.zaremba@intel.com> <20260304185531.4f49fda4@kernel.org> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20260304185531.4f49fda4@kernel.org> X-ClientProxiedBy: VI1PR03CA0072.eurprd03.prod.outlook.com (2603:10a6:803:50::43) To SN7PR11MB7540.namprd11.prod.outlook.com (2603:10b6:806:340::7) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SN7PR11MB7540:EE_|MN6PR11MB8104:EE_ X-MS-Office365-Filtering-Correlation-Id: a4dfc298-4aee-4d83-c4ea-08de7aad162d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|10070799003|7416014|376014|1800799024; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 2 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?gLsxEeTL5/rTZY+Y56yNFh3QvohGBifYasqWR/wwFZv3UE15KyZ7Oi6fQBjj?= =?us-ascii?Q?1GcHgd8pxsrG1hANXGr0hWzgINrT3RyUzvBuYatSlW2VS3RzFcPKdIokj+Ll?= =?us-ascii?Q?QokY9tAgWJi9OIVnZfdptb1oljNB7FeTaGjzMjNEv/ouw2Rzq8zoeQlmRWzf?= =?us-ascii?Q?j6d/300/5gM+7ntpvYAe7Sq1dKIDfoxLjUctbhI3+eOnliO5h+tGWyb51VBZ?= =?us-ascii?Q?esePJJisT3El7VNEXbVMsd6fnqjHpyGW3xCmq5BkEdYpudyLMYpgPBGKPE4z?= =?us-ascii?Q?ElX6iGpiAEIweDmhgWFQhbISjzUNOSONYZcSj3S7jeCSm3dqMbKy72KU0LoX?= =?us-ascii?Q?+6ydBRRZAC3KFtce/dbyZXRcLTM/KPNNZ4IyUoMhO9RU2iE3nlfQeJDbPzBf?= =?us-ascii?Q?MWy4ZQC2xzxvfEc8sOvD5krf14v7F6fv6psKAKYHrbzfriLpFi/jPqwALsiW?= =?us-ascii?Q?fX/geRCkKVb8HzoJEGJgn++wt77lZdniJqDPTcOj9o1TVx/UoUWRjKnt6bcP?= =?us-ascii?Q?c81E6OPkqDSVUd0OdjSSNdmxfTK/ZChM1DkWvpN2L7M2htjIoQYdzTNfUFJf?= =?us-ascii?Q?d/TC/QBwALktZ/s2auklL3jx+OIygB4onCa4HIBcBchCwbeX3+0WDcdcpB2f?= =?us-ascii?Q?Ao0FLeySEqMNc4csGJ798gc5Gwg1n6wf01ZxR9cw9MpZVQ4KiXNkVqC+5MYt?= =?us-ascii?Q?0qpsr2eF+ovTmt2fH+BAhQn4pd1/Har81wjwWLOPw5Bo1Vm2drV07sXckn8F?= =?us-ascii?Q?6jZC9ERNq7imSztUcu6JN1D1LfWxiP3Qu/mJdwfnDtcaZEpd4lf5vmJsXFe0?= =?us-ascii?Q?m8T5gYPXfALi915DbbZwbm5U6xJcgM8NtvMIycBtKQWffw7k9fI+KpC2dU2l?= =?us-ascii?Q?aqaxD94LghcHYT6dv+HGwhdLhz/yKIHIAWA27MLkjJ1YPy5zR2cvsM92DkuG?= =?us-ascii?Q?Nbuoi3TB+jQQXAjoigRP5Y8ccHUrkmGhtoBGFDpeT5sehLVeK0Iy1MnxMzhd?= =?us-ascii?Q?e7oIHOCyAfvj5tGjSDZ7Y5NWeyOrff5rwgeIbb/QbqmuofiKwjLhk/UAQswi?= =?us-ascii?Q?V53G2j+QfWSyHvGGahK5Pr5uciZRw9EhwJqP3QAh8xH7RfwVWMASlMZSNWla?= =?us-ascii?Q?8VblSURPwNxOukVGqYQuqfWRjat8zIEaeJ0zTr0OxBDfrzx/YaruXC8CAwOj?= =?us-ascii?Q?dyLV68PpDBSvsDLGchXFV5itIi+h4H5OfKAQk1k7Aqg9Q/G93nseHyHc/ijr?= =?us-ascii?Q?dYLFlAWjknIpx4X/Aey5QgA1u45g1bGWgxj+3w6wAviDXO+12J18ty7C/vib?= =?us-ascii?Q?yU12J2wck1d0fPpAqVQV00xm7wRA0IIoIK/VbKBVyiIIp2MoJDDRa6UqsoSI?= =?us-ascii?Q?Mep0UgMAdupW5aTL509ebPbQkUTLqfB3DwpX/CHo0Qiu3Pi73Ss2hIEQflgV?= =?us-ascii?Q?eKBb4Hp3KxDChtmKzz4u/c1Wp6YDUCNwexo72Hwbpg2VcoasV41B2buYJPYr?= =?us-ascii?Q?T7tFQz9MtmUyLHVBpU2NlQ+udi3TtVWQKK97FMB+nCgto418Zg5Q0OtIpGQ/?= =?us-ascii?Q?7rTIDtjOChfUfPPe+Ra9BAFBJkmPvirmrNL8FP58neLwk661+BJumQJ8pOZq?= =?us-ascii?Q?949LOsUKdJlY5Gj9HqvPB5+Gon60+rMDZ3p2vUmeMTwpFdrpmH6SHHOCtOh7?= =?us-ascii?Q?nXS5N8bn+igRKevLNyuK0cNur07ojVJ4utJGCHOgC9wOAh/q9LIy1/xlo6Za?= =?us-ascii?Q?qlmBMb94TWvoraSK6DbnARjs+v7h2e491y796oFSGt7ewsYNSo+NtvJzp/Qi?= X-MS-Exchange-AntiSpam-MessageData-1: 5PJ5DmFq98LS0eZRVDoK3cvhjVdKd+oBFMA= X-MS-Exchange-CrossTenant-Network-Message-Id: a4dfc298-4aee-4d83-c4ea-08de7aad162d X-MS-Exchange-CrossTenant-AuthSource: SN7PR11MB7540.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Mar 2026 11:48:15.4428 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: TOuK5bNgb4QL6QOhhvbhjJYNHycOHIB0TQKtfuXsMCsK5+A7EUkS1ups9tlEn4JgjLaIPfOCi+BnF5U0mY+YP2/aW/55MS9tBLBlElb1zgI= X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN6PR11MB8104 X-OriginatorOrg: intel.com On Wed, Mar 04, 2026 at 06:55:31PM -0800, Jakub Kicinski wrote: > On Mon, 2 Mar 2026 17:17:13 +0100 Larysa Zaremba wrote: > > Aside from the issue described below, tailroom calculation does not account > > for pages being split between frags, e.g. in i40e, enetc and > > AF_XDP ZC with smaller chunks. These series address the problem by > > calculating modulo (skb_frag_off() % rxq->frag_size) in order to get > > data offset within a smaller block of memory. Please note, xskxceiver > > tail grow test passes without modulo e.g. in xdpdrv mode on i40e, > > because there is not enough descriptors to get to flipped buffers. > > This was re-assigned to netdev in pw, I presume by BPF maintainers. > But it doesn't apply to net. There's a conflict in ice. > Could you rebase on net and repost? > I have just sent v5 with net as a base tree, had to fix one other thing anyway.