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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?nLAh5jl8K9bSIO7s1TUwfhdd9QSZNuI4Pb25NEvpayCFRY2GVkMvWa76PnVG?= =?us-ascii?Q?qm9112/WCc4dYykxnTafTpDe2KB3aRBM2HPF5a/OtHM0ZMdOkhkY+0dx2N1y?= =?us-ascii?Q?yeUHt1AdptVnio6f6sBFqx642WKszrW2TtEssVUsDDrnFuYZoQgDEHIFlgrA?= =?us-ascii?Q?s+bfYYdUW+0ZNYzumqnJmWQyi7J52zZgJwRr3/b+jyXvg2MvcVsVLBdNLQrA?= =?us-ascii?Q?iJoah41Qucsz6PXJDtw2N73q4HOtgTzmypVQjys5V5h5am3uWGWov2usG/cf?= =?us-ascii?Q?nBtTkcdS4UpryTBS1NF+1HdgBOhmtnaqc0lZLwje2nl1Q85FlKz2s6eMAytR?= =?us-ascii?Q?jdIIDSzDF2jMgiVRu0pLRUJr8lgpX6FAKvKJ2Dx10CuQdMQlCg/K+iXL/4NV?= =?us-ascii?Q?3MAvpWsNEwJtKqHDJyF2pzl6fG64j5pcVmlm0fORHmjd3Vn+daCGM0nQwZmp?= =?us-ascii?Q?nbgPPq8Tr6AjCI5f2r3wQ0+McLtZOqTUz7egdsNU7CHmX5n4BMDmMYC5fZQt?= =?us-ascii?Q?0Q/5nSZIgTqc7d3vN6Dmjd1jrM3i166xRZQUHROYhoG9qhayROzgvZfCa4zQ?= =?us-ascii?Q?G3RLjAMUyJFUX+ADftp1+kP3pr274fwwIKQqtjHivE+DT3iWxP00WQzQpxx5?= =?us-ascii?Q?0Jxb/cEZzLqZWh2a0PKkRuSm3yYmINPVvhU17e9J84FrJYlDNcddJaYYYJEN?= =?us-ascii?Q?HJIfA3PJYKgj6Cy+0/XJBBj8J3eMEsECLpAdFNm48KYWNoLjaVJthbMQ4VAq?= =?us-ascii?Q?Wpf/bY8VF+HzgOlsFr72F9hplmzYKhAagv9kOX6u6w+3t3bQ91P0LEYoQgrq?= =?us-ascii?Q?mm7nd/LtbXPWZZUJM5k54N2fI9CQ99uMmvSFDjbYpZ7PBPa2LmSdtOSOalH8?= =?us-ascii?Q?aQc5p6Al2MTXBXginGPWBx5d28O2CnjIeDOdYnVfvDlBev3TvKbUggCrTy32?= =?us-ascii?Q?jZWPQr5EUb2GdOzcoQct4rgay2FhFnK+w2oIHgqWVZvQ+Pu5L79Hd+q1Wqe/?= =?us-ascii?Q?zj/MUvy7V9PnGN+zUxjnIQCgkzk/5pCQjuJvTTSbuTOAcJP1HojSHlQxV+GH?= =?us-ascii?Q?WCgPztTogCmumVCB6u2FY1bkBHohonfvN/dTQ1O6fFPmrn9rPr304uzl4w7h?= =?us-ascii?Q?9dNxl8l8XeWnb1Hq3xvIJ24TcPR367kCufol5JuYn7UgAu+hBS5FQ/tS+ifd?= =?us-ascii?Q?y4AgvrACwSVfIgGSGEokTc9LFr2NT8wmU/Q6lKpmlJSmPWnS4ONMFtReMXLv?= =?us-ascii?Q?lcXZq8GRbLmP0aeO8fxMF/M3EES6dHGH7hajJ3s1kISwSHO0yiUjQDSA3iE2?= =?us-ascii?Q?g0iDSx6J592FBcfaXeL0VKZb0BQA4tZGEy4bc1VJCqP1oDCBp9HaPYUpOT2r?= =?us-ascii?Q?qw4PyMgCotZ+6UHzI5iIs525mqkUr7Qn62/PpDGOKO5olNhbP7qPgoTc2sKM?= =?us-ascii?Q?BwSIO5kcTl405QYP9NnRjvq51uxj2LJ5LHJzu/Dke0pvfZHMPrX64GEZuWBc?= =?us-ascii?Q?FRc/Ctk4iy34VayzyWBfhKS/VAMxT+BK+a/2l0FiJUDdZxie499eGSqOsiVr?= =?us-ascii?Q?zerdjUsFFWIHVme/N6KgMku1XUjzH5Z+JJALblWG?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 25e9879e-2766-4077-d569-08dcbc7937d5 X-MS-Exchange-CrossTenant-AuthSource: DM4PR12MB7767.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Aug 2024 15:53:19.5743 (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: pBKZyCKXQiyroetJ1VspJbPc8Ko6/qgUFb57b8I14jflvNHfR2Jy7glNwYlB5mq9 X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR12MB7880 On Wed, Aug 14, 2024 at 11:23:41AM -0400, Peter Xu wrote: > On Wed, Aug 14, 2024 at 09:40:00AM -0300, Jason Gunthorpe wrote: > > On Fri, Aug 09, 2024 at 12:08:53PM -0400, Peter Xu wrote: > > > We need these special bits to be around to enable gup-fast on pfnmaps. > > > > It is not gup-fast you are after but follow_pfn/etc for KVM usage > > right? > > Gup-fast needs it to make sure we don't pmd_page() it and fail early. So > still needed in some sort.. Yes, but making gup-fast fail is not "enabling" it :) > But yeah, this comment is ambiguous and not describing the whole picture, > as multiple places will so far rely this bit, e.g. fork() to identify a > private page or pfnmap. Similarly we'll do that in folio_walk_start(), and > follow_pfnmap. I plan to simplify that to: > > We need these special bits to be around on pfnmaps. Mark properly for > !devmap case, reflecting that there's no page struct backing the entry. Yes Jason