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authorSteve Capper <steve.capper@linaro.org>2014-03-21 10:55:36 +0000
committerSteve Capper <steve.capper@linaro.org>2014-09-01 11:58:27 +0100
commitd3dae122b108edf27fcd8d05fcac928ad274a278 (patch)
treec7802e2235e8f30de5e20bedbefe43b5258b0bcc
parent0e169dc51e89ef1ca2ce9e49441d68764d385bbe (diff)
downloadlinux-fast_gup/for_kevin.tar.gz
arm64: mm: Enable RCU fast_gupfast_gup/for_kevin
Activate the RCU fast_gup for ARM64. 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. Some pre-requisite functions pud_write and pud_page are also added. Signed-off-by: Steve Capper <steve.capper@linaro.org> Tested-by: Dann Frazier <dann.frazier@canonical.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [steve.capper@linaro.org: rebased against 3.15-rc8]
-rw-r--r--arch/arm64/Kconfig3
-rw-r--r--arch/arm64/include/asm/pgtable.h22
-rw-r--r--arch/arm64/mm/flush.c15
3 files changed, 39 insertions, 1 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 24203903d93..9db5ee36994 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -95,6 +95,9 @@ config GENERIC_CALIBRATE_DELAY
config ZONE_DMA
def_bool y
+config HAVE_GENERIC_RCU_GUP
+ def_bool y
+
config ARCH_DMA_ADDR_T_64BIT
def_bool y
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7b1c67a0b48..f67a6b17127 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -227,6 +227,16 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
#define __HAVE_ARCH_PTE_SPECIAL
+static inline pte_t pud_pte(pud_t pud)
+{
+ return __pte(pud_val(pud));
+}
+
+static inline pmd_t pud_pmd(pud_t pud)
+{
+ return __pmd(pud_val(pud));
+}
+
static inline pte_t pmd_pte(pmd_t pmd)
{
return __pte(pmd_val(pmd));
@@ -244,7 +254,13 @@ static inline pmd_t pte_pmd(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) pte_special(pmd_pte(pmd))
-#endif
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
+struct vm_area_struct;
+void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmdp);
+#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#define pmd_young(pmd) pte_young(pmd_pte(pmd))
#define pmd_wrprotect(pmd) pte_pmd(pte_wrprotect(pmd_pte(pmd)))
@@ -265,6 +281,8 @@ static inline pmd_t pte_pmd(pte_t pte)
#define mk_pmd(page,prot) pfn_pmd(page_to_pfn(page),prot)
#define pmd_page(pmd) pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))
+#define pud_write(pud) pte_write(pud_pte(pud))
+#define pud_pfn(pud) (((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
#define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
@@ -354,6 +372,8 @@ static inline pmd_t *pud_page_vaddr(pud_t pud)
/* Find an entry in the second-level page table.. */
#ifndef CONFIG_ARM64_64K_PAGES
+#define pud_page(pud) pmd_page(pud_pmd(pud))
+
#define pmd_index(addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
{
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index e4193e3adc7..bed31308d36 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -103,3 +103,18 @@ EXPORT_SYMBOL(flush_dcache_page);
*/
EXPORT_SYMBOL(flush_cache_all);
EXPORT_SYMBOL(flush_icache_range);
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+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 */
+ kick_all_cpus_sync();
+}
+#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */