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helo=mail.nvidia.com; pr=C", "permerror client-ip=40.93.201.1;\n envelope-from=saviram@nvidia.com;\n helo=CY3PR05CU001.outbound.protection.outlook.com" ], "From": "Stav Aviram <saviram@nvidia.com>", "To": "<kernel-team@lists.ubuntu.com>", "Subject": "[SRU][N:linux-bluefield][PATCH v1 0/1] net: page_pool: scale alloc\n cache with PAGE_SIZE", "Date": "Sun, 5 Apr 2026 12:02:38 +0300", "Message-ID": "<cover.1775379454.git.saviram@nvidia.com>", "X-Mailer": "git-send-email 2.47.0", "MIME-Version": "1.0", "X-Originating-IP": "[10.126.230.35]", "X-ClientProxiedBy": "rnnvmail203.nvidia.com (10.129.68.9) To\n rnnvmail201.nvidia.com (10.129.68.8)", "X-EOPAttributedMessage": "0", "X-MS-PublicTrafficType": "Email", "X-MS-TrafficTypeDiagnostic": "BN2PEPF000044A7:EE_|IA1PR12MB8222:EE_", "X-MS-Office365-Filtering-Correlation-Id": "509100b4-c1c5-462e-d9ed-08de92f228d2", "X-MS-Exchange-SenderADCheck": "1", "X-MS-Exchange-AntiSpam-Relay": "0", "X-Microsoft-Antispam": "BCL:0;\n ARA:13230040|36860700016|376014|82310400026|1800799024|13003099007|56012099003|18002099003;", "X-Microsoft-Antispam-Message-Info": "\n p5ot3I5VOTF4nntlmXJm31CDTu38PP/qFIs1e3IKVbqMQZjI232Djl/F6Nzu8PIJturu4U6q+iHwenhBqDVp2J8SI/qVP5bBnW2fnM1bbLVDegaaCaEnO/6Jw8G7l89mUNyIPRvzHIteOfuXaKY17J8kc8EsTmQXtIYtBIRoX4cxRdJpNdWhyrQ09XOOKXV95uabG1WpPgAP2MpViMqoZh69ai8IvJ5kplj2zccYEpIPPKHDaihFsRSRaEFUfpIOPo0qgZJAabAhG2IbZODeKFC27uHzWd9N/d2mruFnkP2Zg7J09Xm/eRDUc+/1MHZFW/0zzRM5sXVZdeCAcvxRC8NL1jT82hFI2VGs3prKg+binuCvsTHOB92+SReesEgz0B+J7fPlaDh4PTbIO3rbVIugz8keJ688+WoCRzSKoXkKqytnkRCBExCrA5SzeJYbE+nO4n/y20/M2S8o8meuhkPty/biBjgJICGcHrJQD3gzONmCEW/k+IuvH4HOoCzxNwzU2m+xYwDKG/kMYPFDA2vxoPA5g1SKL07DOdTsWy9Y+mUS4O8zMX9lEvBz4W7wJFkLC54E5S6xxxfR9wclrHe1WyJgqh6gWoBdW8xBAu1H8zVvUEbRVOc3mKeVuUurXd0O9Nu/pjTz6zYafeRzNRAxwb8vfOJoirqSVOUPVEn+LXw3wZA77Wdy199xsKnIOvzPD+uY7mWTfNnsWA9XLUg50VWMHCyp2ng07dNQuG3RTtUBiCEdbS8KNNt9by2tuw3stWsVT6VQhUapEX+bGA==", "X-Forefront-Antispam-Report": "CIP:216.228.117.160; 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Ip=[216.228.117.160];\n Helo=[mail.nvidia.com]", "X-MS-Exchange-CrossTenant-AuthSource": "\n BN2PEPF000044A7.namprd04.prod.outlook.com", "X-MS-Exchange-CrossTenant-AuthAs": "Anonymous", "X-MS-Exchange-CrossTenant-FromEntityHeader": "HybridOnPrem", "X-MS-Exchange-Transport-CrossTenantHeadersStamped": "IA1PR12MB8222", "X-BeenThere": "kernel-team@lists.ubuntu.com", "X-Mailman-Version": "2.1.20", "Precedence": "list", "List-Id": "Kernel team discussions <kernel-team.lists.ubuntu.com>", "List-Unsubscribe": "<https://lists.ubuntu.com/mailman/options/kernel-team>,\n <mailto:kernel-team-request@lists.ubuntu.com?subject=unsubscribe>", "List-Archive": "<https://lists.ubuntu.com/archives/kernel-team>", "List-Post": "<mailto:kernel-team@lists.ubuntu.com>", "List-Help": "<mailto:kernel-team-request@lists.ubuntu.com?subject=help>", "List-Subscribe": "<https://lists.ubuntu.com/mailman/listinfo/kernel-team>,\n <mailto:kernel-team-request@lists.ubuntu.com?subject=subscribe>", "Content-Type": "text/plain; charset=\"utf-8\"", "Content-Transfer-Encoding": "base64", "Errors-To": "kernel-team-bounces@lists.ubuntu.com", "Sender": "\"kernel-team\" <kernel-team-bounces@lists.ubuntu.com>" }, "content": "BugLink: https://bugs.launchpad.net/bugs/2147290\n\nSRU Justification:\n\n[Impact]\nOn BlueField-3 DPU with linux-bluefield-6.8 kernel (based on Ubuntu 24.04 noble), creating a large number of sub-functions (SFs) via devlink (for example 1600+ `devlink port add ... flavour pcisf` instances) causes severe host memory pressure. In the reported scenario, available memory dropped from roughly 22 GiB to about 4 GiB after creating on the order of 1685 SFs, while total used memory rose dramatically.\nThe root cause is that `page_pool` uses fixed alloc-cache sizing (`PP_ALLOC_CACHE_SIZE` / `PP_ALLOC_CACHE_REFILL`) tuned for 4 KiB pages and NAPI/XDP behavior. On BlueField kernels (Ubuntu 24.04 Noble and Ubuntu 22.04 Jammy based kernels), each cached entry corresponds to a much larger backing page, so the same object counts multiply the per-pool memory footprint. Many network devices allocate page pools per queue or logical port; scaling SF count multiplies that cost and can exhaust memory on 32 GiB systems even when traffic is idle.\n\n[Fix]\nCherry picking the upstream commit:\n\"net: page_pool: scale alloc cache with PAGE_SIZE\"\nThe change scales `PP_ALLOC_CACHE_REFILL` (and hence `PP_ALLOC_CACHE_SIZE`, which remains twice the refill watermark) by `PAGE_SIZE` so that cache footprint in bytes is balanced across page sizes. On 4 KiB page builds the values stay 64 / 128; on 16 KiB and 64 KiB pages they are reduced (16 / 32 and 4 / 8 respectively), cutting redundant cached page capacity where the old constants were grossly oversized.\n\n[Test Case]\nCompiled tested on linux-bluefield-6.8 on master-next branch.\n\n[Regression Potential]\nLow. The change is confined to compile-time constants in `include/net/page_pool/types.h`, and was accepted upstream.\n\nNimrod Oren (1):\n net: page_pool: scale alloc cache with PAGE_SIZE\n\n include/net/page_pool/types.h | 11 ++++++++++-\n 1 file changed, 10 insertions(+), 1 deletion(-)" }