Messages in this thread | | | Date | Wed, 25 Jan 2023 11:20:03 +0100 | Subject | Re: [PATCH mm-unstable v2 1/6] mm: Add folio_estimated_mapcount() | From | David Hildenbrand <> |
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On 24.01.23 02:22, Vishal Moola (Oracle) wrote: > folio_estimated_mapcount() takes in a folio and calls page_mapcount() on > the first page of that folio. > > This is necessary for folio conversions where we only care about either the > entire_mapcount of a large folio, or the mapcount of a not large folio. > > This is in contrast to folio_mapcount() which calculates the total > number of the times a folio and its subpages are mapped. > > Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> > --- > include/linux/mm.h | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index c9db257f09b3..543c360f7ecc 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -875,6 +875,11 @@ static inline int page_mapcount(struct page *page) > return mapcount; > } > > +static inline int folio_estimated_mapcount(struct folio *folio) > +{ > + return page_mapcount(folio_page(folio, 0)); > +} > + > int folio_total_mapcount(struct folio *folio); > > /**
I'm sorry, but "estimated" as absolutely unclear semantics. You could have a THP mapped into 9999 processes using THP and the estimation would be "0".
Huh? Absolutely unclear and confusing. No thanks.
-- Thanks,
David / dhildenb
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