Recently, I got a report get_user_pages_fast helps app's launching time due to reducing uninterruptible sleep time because it could reduce mmap_sem lock contentions when app is launching.
To support gupf in ARM-non-LPAE, first patch reorders memory type table to use 5th bit of the page table. It seems we don't use the bit in ARMv6+ but it needs double check from maintainers. Second patch introduces L_PTE_SPECIAL for arm so that last patch can support get_user_pags_fast. I would greatly appreciate if guys review that I screw up something, especially, architecture stuffs. Thanks. Minchan Kim (3): arm: mm: reordering memory type table arm: mm: introduce L_PTE_SPECIAL arm: mm: support get_user_pages_fast arch/arm/Kconfig | 2 +- arch/arm/include/asm/pgtable-2level.h | 16 +- arch/arm/include/asm/pgtable-3level.h | 6 - arch/arm/include/asm/pgtable.h | 13 ++ arch/arm/mm/Makefile | 6 + arch/arm/mm/gup.c | 221 ++++++++++++++++++++++++++ arch/arm/mm/proc-macros.S | 16 +- 7 files changed, 261 insertions(+), 19 deletions(-) create mode 100644 arch/arm/mm/gup.c -- 2.19.0.rc1.350.ge57e33dbd1-goog
