[RFC PATCH 0/9] Enable THP migration for all possible architectures

[Zi Yan <zi.yan@sent.com>]

From: Zi Yan <zi.yan@cs.rutgers.edu>

Hi all,

THP migration is only enabled on x86_64 with a special
ARCH_ENABLE_THP_MIGRATION macro. This patchset enables THP migration for
all architectures that uses transparent hugepage, so that special macro can
be dropped. Instead, THP migration is enabled/disabled via
/sys/kernel/mm/transparent_hugepage/enable_thp_migration.

I grepped for TRANSPARENT_HUGEPAGE in arch folder and got 9 architectures that
are supporting transparent hugepage. I mechanically add __pmd_to_swp_entry() and
__swp_entry_to_pmd() based on existing __pte_to_swp_entry() and
__swp_entry_to_pte() for all these architectures, except tile which is going to
be dropped.

I have successfully compiled all these architectures, but have NOT tested them
due to lack of real hardware. I appreciate your help, if the maintainers of
these architectures can do a quick test with the code from
https://github.com/x-y-z/thp-migration-bench . Please apply patch 9 as well
to enable THP migration.

By enabling THP migration, migrating a 2MB THP on x86_64 machines takes only 1/3
time of migrating equivalent 512 4KB pages.

Hi Naoya, I also add soft dirty support for powerpc and s390. It would be great
if you can take a look at patch 6 & 7.

Feel free to give comments. Thanks.

Cc: linux-mm@kvack.org
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
Cc: Russell King <linux@armlinux.org.uk>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Kristina Martsenko <kristina.martsenko@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: x86@kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: linux-mips@linux-mips.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Janosch Frank <frankja@linux.vnet.ibm.com>
Cc: linux-s390@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: "Huang, Ying" <ying.huang@intel.com>


Zi Yan (9):
  arc: mm: migrate: add pmd swap entry to support thp migration.
  arm: mm: migrate: add pmd swap entry to support thp migration.
  arm64: mm: migrate: add pmd swap entry to support thp migration.
  i386: mm: migrate: add pmd swap entry to support thp migration.
  mips: mm: migrate: add pmd swap entry to support thp migration.
  powerpc: mm: migrate: add pmd swap entry to support thp migration.
  s390: mm: migrate: add pmd swap entry to support thp migration.
  sparc: mm: migrate: add pmd swap entry to support thp migration.
  mm: migrate: enable thp migration for all possible architectures.

 arch/arc/include/asm/pgtable.h               |  2 ++
 arch/arm/include/asm/pgtable.h               |  2 ++
 arch/arm64/include/asm/pgtable.h             |  2 ++
 arch/mips/include/asm/pgtable-64.h           |  2 ++
 arch/powerpc/include/asm/book3s/32/pgtable.h |  2 ++
 arch/powerpc/include/asm/book3s/64/pgtable.h | 17 ++++++++++++
 arch/powerpc/include/asm/nohash/32/pgtable.h |  2 ++
 arch/powerpc/include/asm/nohash/64/pgtable.h |  2 ++
 arch/s390/include/asm/pgtable.h              |  5 ++++
 arch/sparc/include/asm/pgtable_32.h          |  2 ++
 arch/sparc/include/asm/pgtable_64.h          |  2 ++
 arch/x86/Kconfig                             |  4 ---
 arch/x86/include/asm/pgtable-2level.h        |  2 ++
 arch/x86/include/asm/pgtable-3level.h        |  2 ++
 arch/x86/include/asm/pgtable.h               |  2 --
 fs/proc/task_mmu.c                           |  2 --
 include/asm-generic/pgtable.h                | 21 ++-------------
 include/linux/huge_mm.h                      |  9 +++----
 include/linux/swapops.h                      |  4 +--
 mm/Kconfig                                   |  3 ---
 mm/huge_memory.c                             | 27 +++++++++++++-------
 mm/migrate.c                                 |  6 ++---
 mm/rmap.c                                    |  5 ++--
 23 files changed, 73 insertions(+), 54 deletions(-)

-- 
2.17.0