mm: improve pte updates and dirty/accessed

Time to get this old series out again. Since last time, Bibo found a couple of the same cases I did (for MIPS only) which I extend to all archs, and I dropped the "make the pte dirty if the fork parent was dirty" due to Linus pointing out a dirty PTE costs more to unmap. It didn't seem to help a great deal anyway on the access-side fortunately.

Thanks,
Nick

Nicholas Piggin (3):
mm/cow: don't bother write protecting already write-protected huge
pages
mm/cow: optimise pte accessed bit handling in fork
mm: optimise pte dirty/accessed bit setting by demand based pte
insertion

 arch/mips/include/asm/pgtable.h |  2 --
 include/linux/pgtable.h         | 16 ----------------
 mm/huge_memory.c                | 16 ++++++++++------
 mm/hugetlb.c                    |  2 +-
 mm/memory.c                     | 15 +++++++--------
 mm/migrate.c                    |  1 +
 mm/shmem.c                      |  1 +
 mm/userfaultfd.c                |  2 +-
 mm/vmscan.c                     |  5 +++++
 9 files changed, 26 insertions(+), 34 deletions(-)

2.23.0