Messages in this thread | | | Date | Wed, 7 Dec 2022 16:38:22 -0800 | Subject | Re: [PATCH mm-unstable] mm: clarify folio_set_compound_order() zero support | From | John Hubbard <> |
| |
On 12/7/22 14:37, Sidhartha Kumar wrote: > Document hugetlb's use of a zero compound order so support for zero > orders is not removed from folio_set_compound_order(). > > Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> > Suggested-by: Mike Kravetz <mike.kravetz@oracle.com> > Suggested-by: Muchun Song <songmuchun@bytedance.com> > --- > This can be folded into f2b67a51d0ef6871d4fb0c3e8199f278112bd108 > mm: add folio dtor and order setter functions > > include/linux/mm.h | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 443d496949a8..cd8508d728f1 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -999,9 +999,16 @@ static inline void set_compound_order(struct page *page, unsigned int order) > #endif > } > > +/* > + * folio_set_compound_order is generally passed a non-zero order to > + * initialize a large folio. However, hugetlb code abuses this by > + * passing in zero when 'dissolving' a large folio. > + */
Wouldn't it be better to instead just create a new function for that case, such as:
dissolve_large_folio()
?
> static inline void folio_set_compound_order(struct folio *folio, > unsigned int order) > { > + VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); > + > folio->_folio_order = order; > #ifdef CONFIG_64BIT > folio->_folio_nr_pages = order ? 1U << order : 0;
thanks, -- John Hubbard NVIDIA
| |