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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?RyRauyaYq3cUmYhyTbPiaWRnTK4DvzDA6LfoMzn8OWOerVnJCiHnNfaQ7bgD?= =?us-ascii?Q?jH4IAnH8jCCfRAvLXI242sicwOj8/fvLYVpaR0RT5Tw0ufFBsB+j6wgI7OI2?= =?us-ascii?Q?jYvAdoeYNjouwxqh55ym6B3e+Cb+dSCF8H6OwIfdfv55l53JNF+3YhBbJ9RA?= =?us-ascii?Q?WG2ZtuVE10+345gKr3ZWLur4dey1IZOQeibVsJkVfkZNWicTP/jKAvFO9vBF?= =?us-ascii?Q?vvDqWW127TcBJrARpG+mbyrA5cbRPDqTwcrrUeKaiEpm8qbNQnneyELdxp2B?= =?us-ascii?Q?0sXNH/MoBqY3YQJfsYwTeiyNlZ1o9iwSQMaKrHXYh1jkCoH1ABoh2Y2le/qy?= =?us-ascii?Q?QGE54S24yHAYjLrkw645sMWcgd7jAfkMFpMyIu8HsaP1VYcLTF1LXOvHTZy1?= =?us-ascii?Q?nGnOaUAKpXJfMYiz1xnLF5sLFvUmYNnG0+tYHpKli/gVB1/1ZP48Hm/3z3kT?= =?us-ascii?Q?XcG57AMbgMghU4zUK+yxUqeg+Z/L6YEnaflAVJ4/Bx4Q2Q+kB7wfMvGJYCVO?= =?us-ascii?Q?lk4DbPkHGU3iP6CzDs7hubcIjZOlU6nWDa7ugUo5EouKSwabehVRe6W0KZqE?= =?us-ascii?Q?9ncGREbPQdu9GKKx/xuNKGYsMT2NXl5pIH6FNpWzkyI7/0jQl6TxxCKFuiKX?= =?us-ascii?Q?xkk0wGt5VKa6ydjnU8m1pO2QPJPl6Fvv+b/kSUQ3oY3k8kPjp8K/37GOzLNj?= =?us-ascii?Q?40RBxkTO2VKlNT+M+U9DCR3eqXSL5/e8BXMA8s1ibifkfjJNH3SVZYovgOS0?= =?us-ascii?Q?bMCqFU1iUeVCnpqkhXjaprKNI35sDL9EYQKIKzntPNri52ug/G1Ysnnht75+?= =?us-ascii?Q?sihyKkUuCugAU6o5rjwyxmvkTf+LlYcurhC2QaakRmY1S0+APlBHrVai/nSK?= =?us-ascii?Q?giWeYmUHDaq55uwFXUH0OgS6vd3WVf4pGe+EqO/dXJUVGkeDNGAW+NUy6oUA?= =?us-ascii?Q?8BZEl56Fxyj8froo3stIF2u4ELXe4peD1GQSvT641KM0QOKE+pT4dESjqST6?= =?us-ascii?Q?fF5cOyjTmhwBvd5CksUkuHfu/QU6YOeGmelz9V2E6T6W3CNQ9YHrQ1sO6+te?= =?us-ascii?Q?SVUDU1Lj6DHloLT2dh49Uc1eu1VzUdErfZ2TDOSw/Qz83LV8dL7BWWNiG8jp?= =?us-ascii?Q?tjLl6y6TYkDEVLQc21HwnUxVltH17s0yFmPjD1/zf1bdhDACictc6FWHNrH7?= =?us-ascii?Q?5HSMFwycpCKaV9HL4sv0OX2Q9v/+byguK3vohorsXm6CbqsmpcbuA4p8yhG8?= =?us-ascii?Q?QaKHPbAZbniApanMc3C0iJOPmXBLYNberlR5Xs3QGVX9Y1piDw21ALBB9jt2?= =?us-ascii?Q?UvsCMfMhQL9EMWBNpISBPklXKglK1K7bmmq9qpixjmNM/9nqub73fMalmn6f?= =?us-ascii?Q?qC6AkIrLt7z8ArA2RTgeEU2XW5Te4WAHyNirtVFBXTJATUCFSFtgXaiI7hZj?= =?us-ascii?Q?eIMxPf7x+4FIyV7i5RdJyx0FRZzwL0p6l/qEMYTzNOcSGl/+7oncy03/GIls?= =?us-ascii?Q?k8gzcZhEhQH3L3hCwgnOE0X/cnuqkevhYjA5CS3uX0wp04GAtB6pYEEsSrrS?= =?us-ascii?Q?lG+cSc4jrmq9F649SuDOwLpEPjmbKYNYcjqrS6621aVIig8JYdsQjDUNztsP?= =?us-ascii?Q?PpIHYBitUPMib9I1RDnr+IXw792Tb/liJ1ge+1oZ0NEwbDPDrJS9wVUMdN+B?= =?us-ascii?Q?QtIClHCuCcEpX/Gy6YRdyXrFpTFAlYf91WSfnnq5MMvQuWp6?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2107c9c1-2894-4595-4d8c-08df2fb401fb X-MS-Exchange-CrossTenant-AuthSource: IA0PR12MB8374.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Oct 2026 20:43:48.5150 (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: /SJJ+lIpDshX+ZhMNynH1s0j+MRIHa+KRMIiS7mRPAWLORbt3VsS8lTLmIuRmBq5 X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR12MB4243 On 21 Oct 2026, at 16:36, Konstantin Khorenko wrote: > folio_dup_file_rmap_pmd() passes PGTABLE_LEVEL_PTE to > __folio_dup_file_rmap() for HPAGE_PMD_NR pages, so it adds HPAGE_PMD_NR= > PTE mappings to the folio instead of one PMD mapping. Each unmap of the= > PMD removes one PMD mapping: > > - the folio's mapcount never returns to zero, and removing the folio > from the page cache reports "Bad page cache", or hits a VM_BUG_ON > with CONFIG_DEBUG_VM; > - the first unmap already counts as the last one and drops the > PMD-mapped statistics while the other mm still maps the folio; > - the second one drives the entire mapcount below zero and drops them > again. This chunk of text probably can go away, since no one is affected by the code. > > The helper has no caller yet, the next patch adds the first one. Pass > PGTABLE_LEVEL_PMD, as folio_try_dup_anon_rmap_pmd() does. > > Fixes: d8ef5e311d7b ("mm/rmap: convert page_dup_file_rmap() to folio_du= p_file_rmap_[pte|ptes|pmd]()") > Signed-off-by: Konstantin Khorenko > --- > include/linux/rmap.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > The code change looks good to me. I also find this when I am working on PG_folio. Thanks. Reviewed-by: Zi Yan Best Regards, Yan, Zi