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Diffstat (limited to 'include/linux/mm.h')
| -rw-r--r-- | include/linux/mm.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index f83a1c9ec8e4..104ec00823da 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1727,6 +1727,25 @@ static inline size_t folio_size(struct folio *folio) return PAGE_SIZE << folio_order(folio); } +/** + * folio_estimated_sharers - Estimate the number of sharers of a folio. + * @folio: The folio. + * + * folio_estimated_sharers() aims to serve as a function to efficiently + * estimate the number of processes sharing a folio. This is done by + * looking at the precise mapcount of the first subpage in the folio, and + * assuming the other subpages are the same. This may not be true for large + * folios. If you want exact mapcounts for exact calculations, look at + * page_mapcount() or folio_total_mapcount(). + * + * Return: The estimated number of processes sharing a folio. + */ +static inline int folio_estimated_sharers(struct folio *folio) +{ + return page_mapcount(folio_page(folio, 0)); +} + + #ifndef HAVE_ARCH_MAKE_PAGE_ACCESSIBLE static inline int arch_make_page_accessible(struct page *page) { |