diff options
| author | Steve Capper <steve.capper@linaro.org> | 2014-03-21 10:55:20 +0000 |
|---|---|---|
| committer | Steve Capper <steve.capper@linaro.org> | 2014-08-11 13:28:34 +0100 |
| commit | d6847b8e0b593293174cfc4088e82e0c7414da56 (patch) | |
| tree | b53fd6dcd471dfb58185055030b4aa28c652ec45 | |
| parent | e802048cec008cc69ba73606d13ec036219cdb8d (diff) | |
| download | linux-d6847b8e0b593293174cfc4088e82e0c7414da56.tar.gz | |
arm: mm: Enable RCU fast_gup
Activate the RCU fast_gup for ARM. We also need to force THP splits to
broadcast an IPI s.t. we block in the fast_gup page walker. As THP
splits are comparatively rare, this should not lead to a noticeable
performance degradation.
Signed-off-by: Steve Capper <steve.capper@linaro.org>
| -rw-r--r-- | arch/arm/Kconfig | 6 | ||||
| -rw-r--r-- | arch/arm/include/asm/pgtable-3level.h | 8 | ||||
| -rw-r--r-- | arch/arm/mm/flush.c | 19 |
3 files changed, 32 insertions, 1 deletions
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 4cb4735c5c0..cb8cd24a21f 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -60,7 +60,7 @@ config ARM select HAVE_PERF_EVENTS select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP - select HAVE_RCU_TABLE_FREE if (SMP && CPU_V7) + select HAVE_RCU_TABLE_FREE if (SMP && ARM_LPAE) select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_SYSCALL_TRACEPOINTS select HAVE_UID16 @@ -1713,6 +1713,10 @@ config ARCH_SELECT_MEMORY_MODEL config HAVE_ARCH_PFN_VALID def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM +config HAVE_RCU_GUP + def_bool y + depends on ARM_LPAE + config HIGHMEM bool "High Memory Support" depends on MMU diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h index b286ba9539d..c83b665ae44 100644 --- a/arch/arm/include/asm/pgtable-3level.h +++ b/arch/arm/include/asm/pgtable-3level.h @@ -219,6 +219,8 @@ static inline pte_t pte_mkspecial(pte_t pte) #define __HAVE_ARCH_PMD_WRITE #define pmd_write(pmd) (!(pmd_val(pmd) & PMD_SECT_RDONLY)) +#define pud_write(pud) pmd_write(__pmd(pud_val(pud))) +#define pud_page(pud) pmd_page(__pmd(pud_val(pud))) #define pmd_hugewillfault(pmd) (!pmd_young(pmd) || !pmd_write(pmd)) #define pmd_thp_or_huge(pmd) (pmd_huge(pmd) || pmd_trans_huge(pmd)) @@ -226,6 +228,12 @@ static inline pte_t pte_mkspecial(pte_t pte) #ifdef CONFIG_TRANSPARENT_HUGEPAGE #define pmd_trans_huge(pmd) (pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT)) #define pmd_trans_splitting(pmd) (pmd_val(pmd) & PMD_SECT_SPLITTING) + +#ifdef CONFIG_HAVE_RCU_TABLE_FREE +#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH +void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmdp); +#endif #endif #define PMD_BIT_FUNC(fn,op) \ diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 43d54f5b26b..9422820396d 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -400,3 +400,22 @@ void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned l */ __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE); } + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#ifdef CONFIG_HAVE_RCU_TABLE_FREE +static void thp_splitting_flush_sync(void *arg) +{ +} + +void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmdp) +{ + pmd_t pmd = pmd_mksplitting(*pmdp); + VM_BUG_ON(address & ~PMD_MASK); + set_pmd_at(vma->vm_mm, address, pmdp, pmd); + + /* dummy IPI to serialise against fast_gup */ + smp_call_function(thp_splitting_flush_sync, NULL, 1); +} +#endif /* CONFIG_HAVE_RCU_TABLE_FREE */ +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |