ARM: Tidying up huge pages in 3.11-rc1

Hello,

These two patches tidy up the huge page support in ARM that was introduced in 3.11-rc1.

The first patch removes some duplicate code from arch/arm/mm by referencing the mm/ functions introduced in my ARM64 huge page series.

Whilst the second patch removes a compiler warning in the DMA allocator that appears when huge pages are enabled.

Steve Capper (2):
ARM: mm: Remove general hugetlb code from ARM.
ARM: mm: Remove HugeTLB warning from dma-mapping.c

 arch/arm/Kconfig          |  3 +++
 arch/arm/mm/dma-mapping.c |  3 ---
 arch/arm/mm/hugetlbpage.c | 43 -------------------------------------------
 3 files changed, 3 insertions(+), 46 deletions(-)

1.8.1.4

General forms of huge_pte_alloc, huge_pte_offset and follow_huge_pmd are now available in mm/hugetlb.c.

This patch removes the ARM copies of these functions and activates the general ones by enabling:
CONFIG_ARCH_WANT_GENERAL_HUGETLB

---
 arch/arm/Kconfig          |  3 +++
 arch/arm/mm/hugetlbpage.c | 43 -------------------------------------------
 2 files changed, 3 insertions(+), 43 deletions(-)

index ba412e0..d0fd5bf 100644
@@ -1757,6 +1757,9 @@ config HAVE_ARCH_TRANSPARENT_HUGEPAGE
        def_bool y
        depends on ARM_LPAE
 
+config ARCH_WANT_GENERAL_HUGETLB
+	def_bool y
+
 source "mm/Kconfig"
 
 config FORCE_MAX_ZONEORDER

1.8.1.4

If no-one has any objections should I put this into Russell's patch system?

Cheers,

Steve

Yes please.

Will

I've added it now, its reference is 7792/1.

Cheers,

Steve

The coherant DMA allocator code contained a compile time warning when HugeTLB support was enabled. It stated that huge pages were not supported by the DMA allocator.

Apart from memory pressure, HugeTLB should not affect (or be affected by) the higher order pages operated on by the DMA allocator. Also, the user space mappings returned by arm_dma_mmap are done via remap_pfn_range, so the Transparent Huge Page daemon will leave them alone too.

This patch removes the huge page warning from dma-mapping.c.

---
 arch/arm/mm/dma-mapping.c | 3 ---
 1 file changed, 3 deletions(-)

index 7f9b179..9486048 100644
@@ -249,9 +249,6 @@ static void __dma_free_buffer(struct page *page, size_t size)
 }
 
 #ifdef CONFIG_MMU
-#ifdef CONFIG_HUGETLB_PAGE
-#warning ARM Coherent DMA allocator does not (yet) support huge TLB
-#endif
 
 static void *__alloc_from_contiguous(struct device *dev, size_t size,
 				     pgprot_t prot, struct page **ret_page,

1.8.1.4