On 29 Apr 2026, at 23:29, Zi Yan wrote: > collapse_file() requires FSes supporting large folio with at least > PMD_ORDER, so replace the READ_ONLY_THP_FOR_FS check with that. > MADV_COLLAPSE ignores shmem huge config, so exclude the check for shmem. > > While at it, replace VM_BUG_ON with VM_WARN_ON_ONCE. > > Add a helper function mapping_pmd_folio_support() for FSes supporting large > folio with at least PMD_ORDER. > > Signed-off-by: Zi Yan <[email protected]> > Reviewed-by: Lance Yang <[email protected]> > Reviewed-by: Baolin Wang <[email protected]> > --- > include/linux/pagemap.h | 26 ++++++++++++++++++++++++++ > mm/khugepaged.c | 10 ++++++++-- > 2 files changed, 34 insertions(+), 2 deletions(-) > > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h > index 1f50991b43e3b..1fed3414fe9b8 100644 > --- a/include/linux/pagemap.h > +++ b/include/linux/pagemap.h > @@ -513,6 +513,32 @@ static inline bool mapping_large_folio_support(const > struct address_space *mappi > return mapping_max_folio_order(mapping) > 0; > } > > +/** > + * mapping_pmd_folio_support() - Check if a mapping support PMD-sized folio > + * @mapping: The address_space > + * > + * Some file supports large folio but does not support as large as PMD order. > + * If a PMD-sized pagecache folio is attempted to be created on a filesystem, > + * this check needs to be performed first. > + * > + * Return: true - PMD-sized folio is supported, false - PMD-sized folio is > not > + * supported. > + */ > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +static inline bool mapping_pmd_folio_support(const struct address_space > *mapping) > +{ > + /* AS_FOLIO_ORDER is only reasonable for pagecache folios */ > + VM_WARN_ON_ONCE((unsigned long)mapping & FOLIO_MAPPING_ANON); > + > + return mapping_max_folio_order(mapping) >= PMD_ORDER;
Hi Andrew, Can you help apply the fixup below? It addresses the concern raised by Nico and Lance[1]. Thanks. [1] https://lore.kernel.org/all/[email protected]/ From 9c1749df6516c06b1628ac7804bc7a6ab5709f37 Mon Sep 17 00:00:00 2001 From: Zi Yan <[email protected]> Date: Thu, 7 May 2026 02:02:28 -0400 Subject: [PATCH] fix mapping_pmd_folio_support() to represent its exact meaning Signed-off-by: Zi Yan <[email protected]> --- include/linux/pagemap.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index c6a4ecd3d6ed1..52895896f3357 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -530,7 +530,8 @@ static inline bool mapping_pmd_folio_support(const struct address_space *mapping /* AS_FOLIO_ORDER is only reasonable for pagecache folios */ VM_WARN_ON_ONCE((unsigned long)mapping & FOLIO_MAPPING_ANON); - return mapping_max_folio_order(mapping) >= PMD_ORDER; + return mapping_min_folio_order(mapping) <= PMD_ORDER && + mapping_max_folio_order(mapping) >= PMD_ORDER } #else static inline bool mapping_pmd_folio_support(const struct address_space *mapping) -- 2.53.0 Best Regards, Yan, Zi
