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Wysocki" , Steven Chen , Yan Zhao , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC v1 0/4] Make KHO Stateless Message-ID: <20250917113609.GB1086830@nvidia.com> References: <20250917025019.1585041-1-jasonmiu@google.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250917025019.1585041-1-jasonmiu@google.com> X-ClientProxiedBy: MN2PR05CA0035.namprd05.prod.outlook.com (2603:10b6:208:c0::48) To PH7PR12MB5757.namprd12.prod.outlook.com (2603:10b6:510:1d0::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH7PR12MB5757:EE_|LV9PR12MB9830:EE_ X-MS-Office365-Filtering-Correlation-Id: 71731e70-f007-4559-8484-08ddf5de66a6 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|376014|7416014|366016; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?1Ewm66VGSIZXTG1Gj7Bq1dFqL4yGqxNUSXdWZKNvcNdqUY6Ep4tfFZa4eFGG?= =?us-ascii?Q?aWkytNRKaIwSVabCxokgAYcq4MogjwtjcO88rnFJ91S9rNQrCVid0cJUXHrJ?= =?us-ascii?Q?AcL2PhEZAoutT+LaEpvUrHIEKGU+NzzWnP56T7l3gceJGvYXrk5fps3cJeL0?= =?us-ascii?Q?IZYi/dVrQoryXpL/uffA9dC1549XoOf3gZUBr+it9OwDMXiXJr1pHHaMWNis?= =?us-ascii?Q?GalNanVJioHrxEAOe8mLAq+RoPARBmidM+Vs6M5MYRpGbF99BJTES2saYDAA?= =?us-ascii?Q?2jk2XFj3/LKDnBgrCFn7CIiviuk+N0bAMYSVP5seO/go2V6vA5nFMuLa8nPE?= =?us-ascii?Q?Ov0sX+KLOJdbblJw6nvLl5bi74ekOQNd6HqBstDKlVHUnJSiijIV/9FIIlV5?= =?us-ascii?Q?n20nkPEpRtnU78cc/LJFiky46Bix10NGt6RshbMX+09UXV7B78krKJWHjOhQ?= =?us-ascii?Q?fr3aLsuZM5ySuBrR/ILZSJ3RlcNjhj0DarwLgxPOJu3CUfsMoUTqpu/Dz/7s?= =?us-ascii?Q?jgN2znJEB3ihhHNOmId0pt/ekirCcN1Zp6nxGIAO5+GT6ilhn2aJ91lMO//S?= =?us-ascii?Q?RXqGGH9RGV0sj7tP4duU0NgEWEEparhcZWOqN1WH/R50emd7OmBnKpdGvhNC?= =?us-ascii?Q?OOXHUTfs07vQOTHUP94NCRD6Zzj9OVEZP6sqG42Qg7kHZz4PxbTSyRBbCIHu?= =?us-ascii?Q?dtVFgjWAG+K4KeUevd5ZSAWLGOxCUgZEliz0VPGkPXim7cweEgro/2MbGrg9?= =?us-ascii?Q?HAqHYKKm8JCweALzEJQ+Wle8sfkXMG76KnoOQD518Ownsb/orkyPsmD3rJ2y?= =?us-ascii?Q?Eu83iTcx4szHnsU/LfKBUAjrz8x3k5HbaekTTSIz92PFVVFhBcMgmEzBkaIO?= =?us-ascii?Q?spHQMvqm9Sp3bEBkR/KB2WtK/Ti/R/+2hNZtPUjRJuwViM/4pa0j9hJ2TIiI?= =?us-ascii?Q?TFjf1BDoDnK5PhjYVwPUNo/orbdZ2OuOW7vCP71hCKE/UIZXD8694cGyB7f+?= =?us-ascii?Q?lPvR6RFspdaHLBjddXTrc93ATAebtt5Xh2553qvpdkWv48AUoioXx2vyBjSS?= =?us-ascii?Q?D+79ntgSslbcc4UU1+1YZl6r8NxYlNhqsNbShgSLEeOUp4wk8Ht14HodrcVy?= =?us-ascii?Q?GA9GK5ZUS+gX3rN0bSGaFYkglF6EUJUgrYlHeDf3WjF0oaIlIBe/TniamuBm?= =?us-ascii?Q?wuPu68EioQWzQOEazbRfaBeRd00VMKWfoRbtAKsG18IcguBW48LfyTlOVwlv?= =?us-ascii?Q?rLifea2kboJnG4Rti2HJPSTz8duG/cSj46eNSMzM+o8J9S78bXc8tXq8FCS7?= =?us-ascii?Q?9/Gu9d7+qz9lrMMzsYXmPrU1ntAcIn6d8y+cl793wClnTgae81rU3APGLe/e?= =?us-ascii?Q?hBEwuOvWjYfO21+q4envAjFQPr2LJ3dSpKtBlbBRiFfC0ORtT0z5YKeuk7FP?= =?us-ascii?Q?Y4OLOvHcdp0=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH7PR12MB5757.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(376014)(7416014)(366016);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?cspLpFxZb+k++cOlh0ruLSV3PqUusTmQteQ2QUcNTyOK4gxE5PYWCrwCbxTL?= =?us-ascii?Q?brvD5+UzTtgelv+dmSarnnRZH1PKrC8N2Pp+xt2jojXVO6NthqxgI8P9lhDr?= =?us-ascii?Q?5mB4jQaHsBpwPetGA7ga/N7EGirqy1bwHjbbU3NWw9a7qysbnwVMcByDdajR?= =?us-ascii?Q?iWwOqrBY2ts8TJxUpSHqfa21/P7USe16iRWF1MpK8sBbZUlwsrpvmXeo9a3o?= =?us-ascii?Q?rQMn4TP1vDxUxqKPn2IpgtKITgoboECRkJJrWd674Z1qzUfOuzyoicn+6MRR?= =?us-ascii?Q?ktpX9/nlo6/V4zqbK/JUVbPatgS615W1MznrZeUTUaEawtW03T/u67qOSpRv?= =?us-ascii?Q?4090/adgOXqU48pKvAuYSPDqGrpWsXBBrCgVvBrrWr57BJC+taUdD+zjAMu8?= =?us-ascii?Q?nvZtxuBhRZVTYcA8IjvkxkBzwhqz5mN8VXSlhOG0yKn5q7HTYvOc62sMY0cB?= =?us-ascii?Q?JmMmKnNbuBT97xJVOR2mDyuez89+modsWbumq1vA05RYDUUPlG8uqarWB1rP?= =?us-ascii?Q?tnGXtSua66xw5tDqP7Wi2uizTNGULM0BX+1ce0ru5N87zJqD9Y/SzGgpF/AO?= =?us-ascii?Q?1DO3t5OWTxgCoFww5QTKT7MiFxg7Bg1esTjvt8S3nwXpiAOmG7Pwjls5We8/?= =?us-ascii?Q?CpzjuVpDsoLttPSTSha0MjVtmuwUZUjAo5u3LPP7vTuZCOQzz/Fpfoi/anSV?= =?us-ascii?Q?DA1BW0k+TjT/xk9L5ZWygQbvPtFwMhJ1AEpwHqOppHCwRGQNio6+iC2PeEaI?= =?us-ascii?Q?udERoQD2GG9S2GjDSNTExo/gtgSYz7QP2DBv7PmKQrYblDG5Kw9wRJID0oKe?= =?us-ascii?Q?KSIUkYBi00SoMNDYrAlLOz2qycmLJfAlOozoJwbhcEgbVvuaT1TKcSm1Fwxj?= =?us-ascii?Q?XxqAFtyV3quX4lghO3YS2U+d8mnuG4s6GPFg7txBqX+eeLICVPMnJLSZP5R/?= =?us-ascii?Q?3xUOl1GBhbkzS7oNCowcC4v0qC2yHrtklWuGnqevbOYXYREgNGMFVqYvEPpT?= =?us-ascii?Q?uRssqq06k8wfiD0c73VnTmSW8RnZJ9F7qQDxqoLhEo3/50Ffw0svgUd9CE97?= =?us-ascii?Q?hR/UP0sUhp3eQfvyHaI7mNNcYWXWoCFeeB4evPJCyMAgla8sbDa61SyS5m2c?= =?us-ascii?Q?A+CujjLQXDfg6xMbsDI72/v3jSrdu8S20t86e6NyCyxCOIgHLXIsiWc0487k?= =?us-ascii?Q?3pN+x1D6Op/F2EkQ/EvaL8V+NuUfQPbTYUmcXIcJGlR3N2SMqoPvwTbJP7Zx?= =?us-ascii?Q?+H33Z8mK/fUMu81kmSYVvSxnjp0mSdw5LT+btqo9TPMB2IXA3CfCDpe2CbWe?= =?us-ascii?Q?iiwLgcxtVUqjGizqRkrjcEh5un2oVHP5bpoVK8TGYwu7iENJVHInWMivq5qG?= =?us-ascii?Q?JQSBb4056eKQECvowbMNBtU/WGSEeJXZhOqzycozdzf4aU2+G6rjsy4eeiD2?= =?us-ascii?Q?/tBgkTZWG52la5NFOiFuZxadDqpxcsqWDiaD1wAwu3DYaZBTWo8t3Lj2S9J1?= =?us-ascii?Q?H2rnUEpxG/AKQxUEqxl+yAEr6VUkJYLf4UL+Ff0yilYk25pK1Z7q5jze9G6V?= =?us-ascii?Q?Ghys8yYfKPMgt0rMo0sJFDkQjKfqRMXKc1QRGzmB?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 71731e70-f007-4559-8484-08ddf5de66a6 X-MS-Exchange-CrossTenant-AuthSource: PH7PR12MB5757.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Sep 2025 11:36:11.1534 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: PUF0av98E+vMW771nQhCJWaJ/PEwiFfM66j+1OfG6x7PtX/aJHBiYM6b7d+ed51R X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV9PR12MB9830 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250917_043620_209211_C27930E3 X-CRM114-Status: GOOD ( 11.73 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On Tue, Sep 16, 2025 at 07:50:15PM -0700, Jason Miu wrote: > This series transitions KHO from an xarray-based metadata tracking > system with serialization to using page table like data structures > that can be passed directly to the next kernel. > > The key motivations for this change are to: > - Eliminate the need for data serialization before kexec. > - Remove the former KHO state machine by deprecating the finalize > and abort states. > - Pass preservation metadata more directly to the next kernel via the FDT. > > The new approach uses a per-order page table structure (kho_order_table, > kho_page_table, kho_bitmap_table) to mark preserved pages. The physical > address of the root `kho_order_table` is passed in the FDT, allowing the > next kernel to reconstruct the preserved memory map. It is not a "page table" structure, it is just a radix tree with bits as the leaf. Jason