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U2FsdGVkX19lxwYCx0HHKHEnGHu3rLbtODX0o3aIRMXjvSsjxTxMCQlVcw1H3rq71p8WBf6K8maoHveVKxZCpm2dBupJ6Eteo9y+Vbor6he5j0iBRu5v5H7dbXkG2mGx+N1856gyF5WFOBW35ThkSN/kQdC8vLmoSncd6oHBKAJkkxnHx2OrpTBUPFwqde7p8WtlhWruYl1RyTTclHMIpY5LZr7SeJhxzSaBCaO+HoC6xbV4pQ25oeQkaIMSpKqfrW5ZG7RzV5FM24vGbcLg0O/gDHTURcS2+Swj8EiYpP05WwoebrrqiNCZPlDBzVBkWSbcliXZq8I3L/+Ikfr47QYttEq4MMBE6J/zL3CyZjxf9sB1UkzqhPuNlDGwNZGu8ULwhd0dZF2BJnusA+N7mCok/sfPr1opb2VCEFz0usroZRP4SBm8FVA+0C2YbMqgayPpiQa1o3m6Fsqc+f11HiBzp311mD73KygHAscgzs6Z2LwVytyMjaIzvJC5B9syoSa9B5B2eEzplhefZrEhXUemBeWyO3Ilt+fSZKQx6JFNe2J+ANSr/GJ4C8QsjHcl29ZPIPVAdamV2hlri6j0gh0qEvsMVUS43BalurGiattamfSRY86bC0aIhw0T/GLbRlHkzWG2qUAvUAJv9h6i/HDyQuHNqsF8mwTc77CaYvyWBaTfGGIQPMqDIceFD/PtuIObyj0v3Lol65U4oJoOQUj7iLfmwLtrAanuvSjHTEi3tUpPQjDS+ccUjwx1GXiZZh9YLCei/vFbI43e3aiYZJxcygNp+P283bOxFBFgZr1LhtvRs65XZDwYUv4Fr4vy+cO5TDgMqX3N/WfbWUeWREhXU+qrjhe44Gt87QUPqHIE2sGUPBSbgRVJXpDOJyA677RMqn15siM3KXEy8YpkgSNFAIbqxjBYwuNHRKU8RqwYlPSSv9fLG1Ct/Fh+1pFS5srBw5aeMECVmrXKb9f LxUazr5e +hTd1hyNxoNYsyuIAb/E/Qcy4sVYCs3ekwY1o4sje/VHkaEPvWkzp3XaaXjmxHB+GejQSynB9CC7vKuePMyS2Q+t2hxgfJTxQTXxc3fJZUqgWKod+YAtSMOGYiQXfnXGIe0auRu1kh6N91qiNp0JHpkXGlSwocqn1Ko59sinOFcQofWMejZmIl5M5v5UmadPvFuWmDhJqsSpMtQUMNinOverNrJZDUOiNTecc7LagTMnPh+ddYDkB0auhqLGnjmumJ7sEVClh0AU3eQoWXqEgfRAgWQNcXGT3SmXRARixgahaFumLl2iBMTyO4+5DVSBFm6HxbakuoRpzU9+sNr0alKtQUKSQpcA3v+nRDlkWA+kNmLJIASPuwJihog== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 27 Mar 2026, at 9:37, David Hildenbrand (Arm) wrote: > On 3/27/26 02:42, Zi Yan wrote: >> collapse_file() requires FSes supporting large folio with at least >> PMD_ORDER, so replace the READ_ONLY_THP_FOR_FS check with that. shmem with >> huge option turned on also sets large folio order on mapping, so the check >> also applies to shmem. >> >> While at it, replace VM_BUG_ON with returning failure values. > > Why not VM_WARN_ON_ONCE() ? > > These are conditions that must be checked earlier, no? start & (HPAGE_PMD_NR - 1) yes. I can convert it to VM_WARN_ON_ONCE(). For mapping_max_folio_order(mapping) < PMD_ORDER, I probably should move it to collapse_scan_file() to prevent wasting scanning time if the file does not support large folio. Then, I can turn it into a VM_WARN_ON_ONCE(). Best Regards, Yan, Zi