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 powerpc. 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(-) -- 1.7.10.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>