On 7 May 2026, at 14:08, Zi Yan wrote: > 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]/ >
I was missing a semicolon. Here is the right fixup. Sorry for the noise. From fbd183f7528a3d0bdb421018af4aef45f6366682 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..41dbb55a47d8e 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
