[Patch v3 0/4] mm/mremap: cleanup move_page_tables() a little

[Wei Yang]

move_page_tables() tries to move page table by PMD or PTE.

The root reason is if it tries to move PMD, both old and new range should be
PMD aligned. But current code calculate old range and new range separately.
This leads to some redundant check and calculation.

This cleanup tries to consolidate the range check in one place to reduce some
extra range handling.

v3:
  * merge patch 1 with 2 as suggested by Kirill
  * add patch 4 to simplify the logic to calculate next and extent

v2:
  * remove 3rd patch which doesn't work on ARM platform. Thanks report and
    test from Dmitry Osipenko

Wei Yang (4):
  mm/mremap: it is sure to have enough space when extent meets
    requirement
  mm/mremap: calculate extent in one place
  mm/mremap: start addresses are properly aligned
  mm/mremap: use pmd_addr_end to simplify the calculate of extent

 include/linux/huge_mm.h |  2 +-
 mm/huge_memory.c        |  8 +-------
 mm/mremap.c             | 27 ++++++++++-----------------
 3 files changed, 12 insertions(+), 25 deletions(-)

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2.20.1 (Apple Git-117)