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arm64: mm: enable RCU fast_gup

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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.

[akpm@linux-foundation.org: coding-style fixes]
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>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Steve Capper 2014-10-09 15:29:25 -07:00 committed by Linus Torvalds
parent 5e5f6dc105
commit 29e5694054
3 changed files with 39 additions and 1 deletions
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3
arch/arm64/Kconfig
View File

@ -111,6 +111,9 @@ 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

21
arch/arm64/include/asm/pgtable.h
View File

@ -244,6 +244,16 @@ 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));
@ -261,7 +271,13 @@ 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)))
@ -282,6 +298,7 @@ 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))
@ -381,6 +398,8 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
}
#define pud_page(pud) pmd_page(pud_pmd(pud))
#endif /* CONFIG_ARM64_PGTABLE_LEVELS > 2 */
#if CONFIG_ARM64_PGTABLE_LEVELS > 3

16
arch/arm64/mm/flush.c
View File

@ -104,3 +104,19 @@ 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 */