From: David Hildenbrand <david@xxxxxxxxxx> Subject: mm/huge_memory: remove stale page_trans_huge_mapcount() All users are gone, let's remove it. Link: https://lkml.kernel.org/r/20220131162940.210846-9-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Don Dutile <ddutile@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: Jann Horn <jannh@xxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Liang Zhang <zhangliang5@xxxxxxxxxx> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Nadav Amit <nadav.amit@xxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Peter Xu <peterx@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxxx> Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Yang Shi <shy828301@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mm.h | 5 ---- mm/huge_memory.c | 48 ------------------------------------------- 2 files changed, 53 deletions(-) --- a/include/linux/mm.h~mm-huge_memory-remove-stale-page_trans_huge_mapcount +++ a/include/linux/mm.h @@ -834,16 +834,11 @@ static inline int total_mapcount(struct return folio_mapcount(page_folio(page)); } -int page_trans_huge_mapcount(struct page *page); #else static inline int total_mapcount(struct page *page) { return page_mapcount(page); } -static inline int page_trans_huge_mapcount(struct page *page) -{ - return page_mapcount(page); -} #endif static inline struct page *virt_to_head_page(const void *x) --- a/mm/huge_memory.c~mm-huge_memory-remove-stale-page_trans_huge_mapcount +++ a/mm/huge_memory.c @@ -2483,54 +2483,6 @@ static void __split_huge_page(struct pag } } -/* - * This calculates accurately how many mappings a transparent hugepage - * has (unlike page_mapcount() which isn't fully accurate). This full - * accuracy is primarily needed to know if copy-on-write faults can - * reuse the page and change the mapping to read-write instead of - * copying them. At the same time this returns the total_mapcount too. - * - * The function returns the highest mapcount any one of the subpages - * has. If the return value is one, even if different processes are - * mapping different subpages of the transparent hugepage, they can - * all reuse it, because each process is reusing a different subpage. - * - * The total_mapcount is instead counting all virtual mappings of the - * subpages. If the total_mapcount is equal to "one", it tells the - * caller all mappings belong to the same "mm" and in turn the - * anon_vma of the transparent hugepage can become the vma->anon_vma - * local one as no other process may be mapping any of the subpages. - * - * It would be more accurate to replace page_mapcount() with - * page_trans_huge_mapcount(), however we only use - * page_trans_huge_mapcount() in the copy-on-write faults where we - * need full accuracy to avoid breaking page pinning, because - * page_trans_huge_mapcount() is slower than page_mapcount(). - */ -int page_trans_huge_mapcount(struct page *page) -{ - int i, ret; - - /* hugetlbfs shouldn't call it */ - VM_BUG_ON_PAGE(PageHuge(page), page); - - if (likely(!PageTransCompound(page))) - return atomic_read(&page->_mapcount) + 1; - - page = compound_head(page); - - ret = 0; - for (i = 0; i < thp_nr_pages(page); i++) { - int mapcount = atomic_read(&page[i]._mapcount) + 1; - ret = max(ret, mapcount); - } - - if (PageDoubleMap(page)) - ret -= 1; - - return ret + compound_mapcount(page); -} - /* Racy check whether the huge page can be split */ bool can_split_folio(struct folio *folio, int *pextra_pins) { _
