[PATCH v6 0/4] Fix free/allocation of runtime gigantic pages

Alexandre Ghiti
2019-03-07T13:20:11Z

This series fixes sh and sparc that did not advertise their gigantic page
support and then were not able to allocate and free those pages at runtime.
It renames MEMORY_ISOLATION && COMPACTION || CMA condition into the more
accurate CONTIG_ALLOC, since it allows the definition of alloc_contig_range
function.
Finally, it then fixes the wrong definition of ARCH_HAS_GIGANTIC_PAGE config
that, without MEMORY_ISOLATION && COMPACTION || CMA defined, did not allow
architectures to free boottime allocated gigantic pages although unrelated.

Changes in v6:
- Remove unnecessary goto since the fallthrough path does the same and is
the 'normal' behaviour, as suggested by Dave Hensen
- Be more explicit in comment in set_max_huge_page: we return an error
if alloc_contig_range is not defined and the user tries to allocate a
gigantic page (we keep the same behaviour as before this patch), but we
now let her free boottime gigantic page, as suggested by Dave Hensen
- Add Acked-by, thanks.

Changes in v5:
- Fix bug in previous version thanks to Mike Kravetz
- Fix block comments that did not respect coding style thanks to Dave Hensen
- Define ARCH_HAS_GIGANTIC_PAGE only for sparc64 as advised by David Miller
- Factorize "def_bool" and "depends on" thanks to Vlastimil Babka

Changes in v4 as suggested by Dave Hensen:
- Split previous version into small patches
- Do not compile alloc_gigantic** functions for architectures that do not
support those pages
- Define correct ARCH_HAS_GIGANTIC_PAGE in all arch that support them to avoid
useless runtime check
- Add comment in set_max_huge_pages to explain that freeing is possible even
without CONTIG_ALLOC defined
- Remove gigantic_page_supported function across all archs

Changes in v3 as suggested by Vlastimil Babka and Dave Hansen:
- config definition was wrong and is now in mm/Kconfig
- COMPACTION_CORE was renamed in CONTIG_ALLOC

Changes in v2 as suggested by Vlastimil Babka:
- Get rid of ARCH_HAS_GIGANTIC_PAGE
- Get rid of architecture specific gigantic_page_supported
- Factorize CMA or (MEMORY_ISOLATION && COMPACTION) into COMPACTION_CORE

Alexandre Ghiti (4):
sh: Advertise gigantic page support
sparc: Advertise gigantic page support
mm: Simplify MEMORY_ISOLATION && COMPACTION || CMA into CONTIG_ALLOC
hugetlb: allow to free gigantic pages regardless of the configuration

arch/arm64/Kconfig | 2 +-
arch/arm64/include/asm/hugetlb.h | 4 --
arch/powerpc/include/asm/book3s/64/hugetlb.h | 7 ---
arch/powerpc/platforms/Kconfig.cputype | 2 +-
arch/s390/Kconfig | 2 +-
arch/s390/include/asm/hugetlb.h | 3 --
arch/sh/Kconfig | 1 +
arch/sparc/Kconfig | 1 +
arch/x86/Kconfig | 2 +-
arch/x86/include/asm/hugetlb.h | 4 --
arch/x86/mm/hugetlbpage.c | 2 +-
include/linux/gfp.h | 4 +-
mm/Kconfig | 3 ++
mm/hugetlb.c | 57 ++++++++++++--------
mm/page_alloc.c | 7 ++-
15 files changed, 50 insertions(+), 51 deletions(-)

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2.20.1