Apologies for the noise, I resent this series but neglected to place the word "PATCH" in the subject lines of the patches thus the patches got blocked by the list server. Here is another go at a resend. ---
The following patches bring both HugeTLB support and Transparent HugePage (THP) support to ARM for 2 levels of paging (i.e. without LPAE).
This code has been tested on an Arndale board (Exynos 5250), and is based on 3.11-rc1, with the hugepage simplification patch: http://lists.infradead.org/pipermail/linux-arm-kernel/2013-July/184117.html
HugeTLB and THP support for LPAE has already been merged in 3.11-rc1.
Hugepages can give nice performance boosts to workloads that put pressure on the TLBs. I've observed uplifts of ~5% to some tasks just by enabling hugepages via the libhugetlbfs tools. Other people have observed decent performance boosts when huge pages are enabled: http://lists.infradead.org/pipermail/linux-arm-kernel/2013-February/148835.h...
I would appreciate any discussion on these patches, as there are people who have an interest in having huge page support in non-LPAE kernels.
Steve Capper (2): ARM: mm: HugeTLB support for non-LPAE systems. ARM: mm: Transparent huge page support for non-LPAE systems.
arch/arm/Kconfig | 4 +- arch/arm/include/asm/hugetlb-2level.h | 126 +++++++++++++++++++++++++ arch/arm/include/asm/hugetlb.h | 4 + arch/arm/include/asm/pgtable-2level.h | 170 ++++++++++++++++++++++++++++++++++ arch/arm/include/asm/pgtable-3level.h | 6 ++ arch/arm/include/asm/pgtable.h | 7 +- arch/arm/include/asm/tlb.h | 10 +- arch/arm/kernel/head.S | 10 +- arch/arm/mm/fault.c | 13 --- arch/arm/mm/fsr-2level.c | 4 +- arch/arm/mm/hugetlbpage.c | 2 +- arch/arm/mm/mmu.c | 27 ++++++ 12 files changed, 360 insertions(+), 23 deletions(-) create mode 100644 arch/arm/include/asm/hugetlb-2level.h