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To: wale zhang Cc: Andrew Morton , Barry Song <21cnbao@gmail.com>, chrisl@kernel.org, ziy@nvidia.com, lorenzo.stoakes@oracle.com, matthew.brost@intel.com, linux-mm@kvack.org References: <20251230130110.1366374-1-wale.zhang.ftd@gmail.com> <20251230133522.e15135c3a17826428f472a2e@linux-foundation.org> <4029d13c-3bfc-4ace-8da0-3895dfc001b1@kernel.org> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 9DE8940006 X-Stat-Signature: fcy7ts1wb5tmigwgp6uwrnwpayxwb9pj X-HE-Tag: 1767183426-188877 X-HE-Meta: U2FsdGVkX19cKt16EJ6dqMh2EDs0cZfYP4p8fuzSbeYngXcM/tBuZS3jzUwowvw+cRO6jxpoQvL+g2qQXX+sR36wvh/i4TTos22XF8ffsUrGsM8xsMi21DzU0V8tFEKFKEhrvVzmnLnQLBOdC+ZZbUru30G2KF3OWvOjg5gF5f9mJz7o5UIctoTv0XZcI9gEFX+Hkj0JyGqAtXyTMBKxyPglJ15fHwNppq+yZz5mxVaNQJFjiXUxVLicFMWyK2vLajSODdONUk4dR0T5Ktzm1dZohFvYJ/ylBwSQlgRvx8wVrf8Amw1Jw6hfSWQ0EeQQmVmVyqD9WVowSwrbrkAYMTX7Q1cc+r3HMPAhDp28JUFgeIUGvznIo/2MO0xiIo8WpBl8V4/nyn1JJBbTL9peWvOTlgN/HilLiavgW7r1N9tj0cKXtGD/Y4V+FlczwPtMNQRB6jJhTHhkB6M9BXW6Ag/0CvvabShoECpvq1AIZ5p2RKfUhkU9vQ8IlKBdSAYGR1jDSV7hHlxXwTjlUAJC/gqrkd35ER21NryMWL+sE4YIALHoinjkLnr6GgsQcrYbe5EYv/QIlQ6GxNa8CYwjFVoIMdrJQOEwqnYhUdBcVDbUS1M0Kdsc0LnVihQIJlnmZliTBK7BeJ4lG+dBr+aTVedFrc6EJxuXQTtPps555H9VSc57HxyxnI487jET4O3XENxeB6KBtmqj876OR3YOVUvZOHuWDi9tosExrT5mHlwqZRDhp4Zyolz92/0fqTv8g+ErOxTGOtiz0eLgmJ1DNfrzhHEMrHLSYE+q6/e/48hVRfgcjBp7KfSlXfe3ubVPUP6gMJEhgk4XZYSyKfj1kuncOasG8yCfKz66mq3W9Mgeo2ycRowffReezog2+tITD1ZjXVX19WOwtfC4ViXeB+EStjvUIvkrogF9oD7dXlfATAOmtSlhNbigVjlM/ZPyEbZYX5ly+8WU3EncTAQ r3tEQhJa 51PfoNPSmtHXLhIW7nFW2I8uV6NrEY1GI0eMa6LZRnO424h1gmVXZO2Iy0WW3jmvBUHlFRh4TQbbjxhLBkp++0TNV6rtE2Z5y8Pm7db/KLGhWGNPHOAkwhz6ehDIG+tQAqv5zp73WxATbMh9uvE4aU6OGVW4ol19jXziOe0UysG56wBBmbI5L65aO5z21AW6upe0fCpp41i3BErNbi8puWKKZGlv0kR2LIM/hgyq/474sotkYtxTcfS65ZS1Vph4vSQvQGqnI6mYTl4+m7D1j4hqmgzH78g8DBFkJkd1am43r1aLNN7PQBtMOvlStzojGMkUW0kyDinQ3SXTKqpqpF/MMiGbmdwWz/Q8lg9f1UFZVN4g= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > > Hello David, > > folio_inc_return_large_mapcount and folio_dec_return_large_mapcount > are only used when CONFIG_NO_PAGE_MAPCOUNT is defined. It's conceptually wrong to leak CONFIG_NO_PAGE_MAPCOUNT in something that is CONFIG_MM_ID material at this point. > >> >> >> So if the following makes compilers happy, fine with me: > > Apart from the solution as below, I can't think of any other ways. Do > you have any good ideas? Leave the code alone. What we *could* do is diff --git a/include/linux/rmap.h b/include/linux/rmap.h index daa92a58585d9..ae495c225717a 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -354,11 +354,8 @@ static inline void folio_add_large_mapcount(struct folio *folio, atomic_add(diff, &folio->_large_mapcount); } -static inline int folio_add_return_large_mapcount(struct folio *folio, - int diff, struct vm_area_struct *vma) -{ - BUILD_BUG(); -} +int folio_add_return_large_mapcount(struct folio *folio, + int diff, struct vm_area_struct *vma); static inline void folio_sub_large_mapcount(struct folio *folio, int diff, struct vm_area_struct *vma) @@ -366,11 +363,8 @@ static inline void folio_sub_large_mapcount(struct folio *folio, atomic_sub(diff, &folio->_large_mapcount); } -static inline int folio_sub_return_large_mapcount(struct folio *folio, - int diff, struct vm_area_struct *vma) -{ - BUILD_BUG(); -} +int folio_sub_return_large_mapcount(struct folio *folio, + int diff, struct vm_area_struct *vma); #endif /* CONFIG_MM_ID */ #define folio_inc_large_mapcount(folio, vma) \ But then, I have patches here in the works that actually fill these functions with life. So leave the code alone; I'm sure that is something with more added value to be done in the kernel :) -- Cheers David