[PATCH V4 0/2] mm: FAULT_AROUND_ORDER patchset performance data for powerpc

Madhavan Srinivasan maddy at linux.vnet.ibm.com
Thu May 8 19:28:14 EST 2014

Kirill A. Shutemov with 8c6e50b029 commit introduced
vm_ops->map_pages() for mapping easy accessible pages around
fault address in hope to reduce number of minor page faults.

This patch creates infrastructure to modify the FAULT_AROUND_ORDER
value using mm/Kconfig. This will enable architecture maintainers
to decide on suitable FAULT_AROUND_ORDER value based on
performance data for that architecture. First patch also defaults
FAULT_AROUND_ORDER Kconfig element to 4. Second patch list
out the performance numbers for powerpc (platform pseries) and
initialize the fault around order variable for pseries platform of

V4 Changes:
  Replaced the BUILD_BUG_ON with VM_BUG_ON.
  Moved fault_around_pages() and fault_around_mask() functions outside of
   #ifdef CONFIG_DEBUG_FS.

V3 Changes:
  Replaced FAULT_AROUND_ORDER macro to a variable to support arch's that
   supports sub platforms.
  Made changes in commit messages.

V2 Changes:
  Created Kconfig parameter for FAULT_AROUND_ORDER
  Added check in do_read_fault to handle FAULT_AROUND_ORDER value of 0
  Made changes in commit messages.

Madhavan Srinivasan (2):
  mm: move FAULT_AROUND_ORDER to arch/
  powerpc/pseries: init fault_around_order for pseries

 arch/powerpc/platforms/pseries/pseries.h |    2 ++
 arch/powerpc/platforms/pseries/setup.c   |    5 +++++
 mm/Kconfig                               |    8 ++++++++
 mm/memory.c                              |   25 ++++++-------------------
 4 files changed, 21 insertions(+), 19 deletions(-)


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