[PATCH v2 0/6] Avoid cache trashing on clearing huge/gigantic page

["Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>]

From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>

Clearing a 2MB huge page will typically blow away several levels of CPU
caches.  To avoid this only cache clear the 4K area around the fault
address and use a cache avoiding clears for the rest of the 2MB area.

This patchset implements cache avoiding version of clear_page only for
x86. If an architecture wants to provide cache avoiding version of
clear_page it should to define ARCH_HAS_USER_NOCACHE to 1 and implement
clear_page_nocache() and clear_user_highpage_nocache().

v2:
  - No code change. Only commit messages are updated.
  - RFC mark is dropped.

Andi Kleen (6):
  THP: Use real address for NUMA policy
  mm: make clear_huge_page tolerate non aligned address
  THP: Pass real, not rounded, address to clear_huge_page
  x86: Add clear_page_nocache
  mm: make clear_huge_page cache clear only around the fault address
  x86: switch the 64bit uncached page clear to SSE/AVX v2

 arch/x86/include/asm/page.h          |    2 +
 arch/x86/include/asm/string_32.h     |    5 ++
 arch/x86/include/asm/string_64.h     |    5 ++
 arch/x86/lib/Makefile                |    1 +
 arch/x86/lib/clear_page_nocache_32.S |   30 +++++++++++
 arch/x86/lib/clear_page_nocache_64.S |   92 ++++++++++++++++++++++++++++++++++
 arch/x86/mm/fault.c                  |    7 +++
 mm/huge_memory.c                     |   17 +++---
 mm/memory.c                          |   29 ++++++++++-
 9 files changed, 178 insertions(+), 10 deletions(-)
 create mode 100644 arch/x86/lib/clear_page_nocache_32.S
 create mode 100644 arch/x86/lib/clear_page_nocache_64.S

-- 
1.7.7.6

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