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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?cVlYApRwhpSF+qtyyq/zT8hP9X3qDoSJ30D3fowSaf+BErw3hRtc+QSC0f3V?= =?us-ascii?Q?rMjfJfYtFihEMo2iu0Bl7T/DrL9fBlSlZ0ptMU7SFj9tGAhaD6rzKXhqQX9L?= =?us-ascii?Q?0tyH0Jk7PVtK5b9pf0R/mR7oSzk0/t686+ADpq3lS8deXHe0G2HmufgkAWOK?= =?us-ascii?Q?EQVUawnoDjU9l7GMPv6CtjTCGHxKiPKZFd46zmAj8fYJPnb//hcPzYdcPbkf?= =?us-ascii?Q?ME0LBUUdpd3sGJykPnAsvSlyDVYPvk93jDJoJCnaEJqQltxWzvgTqWWhnI/k?= =?us-ascii?Q?P+Zb+UELc4605QJ6NfJhEKMpvk9W4Tf+a271ZIIWYhJUH/P6QaPKqQSrjBEK?= =?us-ascii?Q?8nlbVo5Y2FltZR8Un4IWNnp+7FiN2AAYrzxoM2GMvrR2SZpOxQUpZUXArYbL?= =?us-ascii?Q?OSyGxFuiBFEPRDUsaqN2fytfXuzI5KPPfO6yjCEEQV3uksxDODMtPAwX118M?= =?us-ascii?Q?XxAAZu38nRbROdLo9Hg5/4AXfFAomr2OKjEPXRo4zrP5caJbSn6wh+kl9q7E?= =?us-ascii?Q?oijhRSiqGb6V90rNkt072A1pBcD9Ibw4MZ79XuN3eCDo9460uWZyZSNuANui?= =?us-ascii?Q?HDAvopW5Pn3iyz0Zf0cPMw1wLqk6fpawOpteBr8CuyjkMU1NPhjs4YhN8nj1?= =?us-ascii?Q?6laElr3UF147jl0/3vEiEI0Di8s769QITWjU7BC1XiLewHr6VXQJOXazscV4?= =?us-ascii?Q?Pj9MlD9XEKlMSeg/Tue7SJHI3IS7TD/lNn5j5XX+tr6NroX1U4yTc96ElP7i?= =?us-ascii?Q?R+FGn5ANGnWJcj250aOaaBNyjtY1vcUZ6dEXC088KgvSv/OBZKF9a+21xmGz?= =?us-ascii?Q?qxMamoti8uPnq/BlvlGKi6HFreRel8AR3Rq0CzH5LISmGK10EajKQEFHy+S7?= =?us-ascii?Q?76N4ZPWhZCxxKpwTQrB0QdNxjP3ZTiK5VOdAsaxLn1mgkJ3+s3pNDOeWfaLv?= =?us-ascii?Q?haTaiABV+Bc2xCum4fxQFn2MMkAjS6dLvnZMILkOV/fyrwPQhMOTFsVEQWdT?= =?us-ascii?Q?rVg4ACrKFPK7B8SN9Rmmq33JgvBVk9NGXzdGtaN0wyD9kyiD0dd/u5wQy1yy?= =?us-ascii?Q?O6Zz+60j2bSYU0jxjPafaEZQ2fseK/eSn6Y+DtbcxCmNIzgOS5dTfSWlmGPz?= =?us-ascii?Q?VHIoP3HBxCGX6bjBdwIQdeAhtQWoINAWk15XEiODUX4fiWSEL+42j5Ft/xM8?= =?us-ascii?Q?NwS9LZCEH2WB9iJqDgx5BZ3CSXklHrwlPDImoVqMdeUS0Cpll+s9ddQ5lwl9?= =?us-ascii?Q?xyG8VKWj8IuwWb/cpp8TiiPHsAKRbVBJ6oHAZdsGzQKiHeQjPyCPn30PHIzj?= =?us-ascii?Q?02jZ/ykjbtMpW4FCRt5rDoqCVDn8Xp0R4Pm31ZM0wJwnsOX/aR700k1BNSTV?= =?us-ascii?Q?dx249o7um34gzBW7UsID0C/Pp1If6l9o3pBoIUx+F9Tfz06fF8rvNVfPK2iH?= =?us-ascii?Q?bzy3aSlxdY2EVp9D7PU1S0sbxMK1WRU05F/9m2Swp1rLBxf2bKpjKt7IhK+d?= =?us-ascii?Q?wZ8m9hNb2agDqzsZlxrF3apJpEvc7YOaeNWAvE3c3SAc0daIrWpUK5pXFkcp?= =?us-ascii?Q?xRCu7WQh621QLMv9Ys058LFExZ85VBJ7QGZ5kwrt?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1d10f62f-de9a-42df-767a-08dc4e701702 X-MS-Exchange-CrossTenant-AuthSource: DS7PR12MB5744.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Mar 2024 15:10:51.0400 (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: BtiVa37goGbrsbwlUBlyuKAxcVAeIDjcG5xuUeGrS5J0AXAH5zC3dkO+JyFR9uke X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB5806 --=_MailMate_C89DDADC-B275-4BEC-B81D-2ECC61EE31C3_= Content-Type: text/plain On 27 Mar 2024, at 10:54, Matthew Wilcox wrote: > On Wed, Mar 27, 2024 at 10:45:42AM -0400, Zi Yan wrote: >>> for (pfn = start_pfn; pfn < end_pfn; pfn++) { >>> - struct folio *folio; >>> + struct page *page, *head; >> >> You could get rid of head too. It is only used to calculate next pfn, >> so pfn = folio_to_pfn(folio) + folio_nr_pages(folio) - 1 would work. >> >> And the PageHuge(page) and PageTransHuge(page) can be simplified, since >> their pfn calculations are the same. Something like: >> >> if (folio_test_large(folio)) { >> pfn = folio_to_pfn(folio) + folio_nr_pages(folio) - 1; >> if (folio_test_hugetlb(folio)) { >> isolate_hugetlb(folio, &source); >> continue; >> } >> } > > How much of this is safe without a refcount on the folio? folio_to_pfn() should be fine, isolate_hugetlb() checks the folio under hugetlb_lock, but folio_nr_pages() might return a bogus number that makes pfn go beyond end_pfn and ends for loop early. The code below increases the refcount, so it might be better to move this part of the code after refcount is increased. -- Best Regards, Yan, Zi --=_MailMate_C89DDADC-B275-4BEC-B81D-2ECC61EE31C3_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQJDBAEBCgAtFiEE6rR4j8RuQ2XmaZol4n+egRQHKFQFAmYENvkPHHppeUBudmlk aWEuY29tAAoJEOJ/noEUByhUvSoP/15yB0YWffJbT+nWkj3irolDJ6mPUTHcUO+W kfWSmZVw22GuYuRm9Z+1Bk4wRjxqyEFZmYPj+ALmKwr6PEUH+nPcga5FW896T3l5 QRIGgtzzRvqbXaFXbE5Osle8HwmXadrTQQYco75sZK9XPmhNLpjcnwT4bKn8wNWa DyQmuQsWKmcUUEidoEBQjSjNI3oewT8rYEoZbCkLeVuGWtKacQz0mMO79ewo/cQ+ r0/ilg0fPx80IzN4eQroL3sOLhrBlNaf+DQiKUSBkM2CcmqfjGw1Rr3AUqpyWsHa regzIembZf1OiieW2BCQhMf48k9ez6O5MgazM7ozNN1929BeqeTMQf0SKMPPMCdB yMq8K+vAd9Xz1jh0EIlb5dtQmiDrc7cY9UQSg7U+8HIw5ANTUBndlEEbNkHNWzW5 ZbRg7sflbojLpX95h1DBkK3vARr8QPER88LnFkwVaVrxWLSCnSGrirvcKrH6gYyN XgevPQOl6ZG3/7qVTt9OruJfu76QKL0kPTVh2jbGJGhgypEpg26O7hYQ+83+ah1z vi3rfK2DBMoDjzF2NyqYa5dQ6YfzyuC6Ld1WFo/DMKdVlyCmhkZhsa7gRaPa1//i +SwsxwIikEpYgTLgRO28+yULHKVKPSzsHopo8SCAU+C3ZOuCto2nRTOz/3He/hzc 7+AeRLso =wbjy -----END PGP SIGNATURE----- --=_MailMate_C89DDADC-B275-4BEC-B81D-2ECC61EE31C3_=--