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From: Steve Capper <steve.capper@linaro.org>
To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com,
	linux@arm.linux.org.uk, linux-arch@vger.kernel.org,
	linux-mm@kvack.org, akpm@linux-foundation.org
Cc: will.deacon@arm.com, gary.robertson@linaro.org,
	christoffer.dall@linaro.org, peterz@infradead.org,
	anders.roxell@linaro.org, dann.frazier@canonical.com,
	mark.rutland@arm.com, mgorman@suse.de,
	Steve Capper <steve.capper@linaro.org>
Subject: [PATCH V3 6/6] arm64: mm: Enable RCU fast_gup
Date: Thu, 28 Aug 2014 15:45:07 +0100	[thread overview]
Message-ID: <1409237107-24228-7-git-send-email-steve.capper@linaro.org> (raw)
In-Reply-To: <1409237107-24228-1-git-send-email-steve.capper@linaro.org>

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>
---
 arch/arm64/Kconfig               |  3 +++
 arch/arm64/include/asm/pgtable.h | 21 ++++++++++++++++++++-
 arch/arm64/mm/flush.c            | 15 +++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index ce9062b..435305e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -108,6 +108,9 @@ 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 ffe1ba0..6d81471 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -239,6 +239,16 @@ 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));
@@ -256,7 +266,13 @@ 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)))
@@ -277,6 +293,7 @@ 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))
@@ -376,6 +393,8 @@ 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
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index 0d64089..2d5fd47 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -104,3 +104,18 @@ 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 */
-- 
1.9.3

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WARNING: multiple messages have this Message-ID (diff)
From: Steve Capper <steve.capper@linaro.org>
To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com,
	linux@arm.linux.org.uk, linux-arch@vger.kernel.org,
	linux-mm@kvack.org, akpm@linux-foundation.org
Cc: will.deacon@arm.com, gary.robertson@linaro.org,
	christoffer.dall@linaro.org, peterz@infradead.org,
	anders.roxell@linaro.org, dann.frazier@canonical.com,
	mark.rutland@arm.com, mgorman@suse.de,
	Steve Capper <steve.capper@linaro.org>
Subject: [PATCH V3 6/6] arm64: mm: Enable RCU fast_gup
Date: Thu, 28 Aug 2014 15:45:07 +0100	[thread overview]
Message-ID: <1409237107-24228-7-git-send-email-steve.capper@linaro.org> (raw)
Message-ID: <20140828144507.U1vhuE3tyZ0ogH3F9sc4dUuY410TEH95gh4T_FtWsBY@z> (raw)
In-Reply-To: <1409237107-24228-1-git-send-email-steve.capper@linaro.org>

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>
---
 arch/arm64/Kconfig               |  3 +++
 arch/arm64/include/asm/pgtable.h | 21 ++++++++++++++++++++-
 arch/arm64/mm/flush.c            | 15 +++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index ce9062b..435305e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -108,6 +108,9 @@ 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 ffe1ba0..6d81471 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -239,6 +239,16 @@ 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));
@@ -256,7 +266,13 @@ 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)))
@@ -277,6 +293,7 @@ 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))
@@ -376,6 +393,8 @@ 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
diff --git a/arch/arm64/mm/flush.c b/arch/arm64/mm/flush.c
index 0d64089..2d5fd47 100644
--- a/arch/arm64/mm/flush.c
+++ b/arch/arm64/mm/flush.c
@@ -104,3 +104,18 @@ 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 */
-- 
1.9.3


  parent reply	other threads:[~2014-08-28 14:45 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-28 14:45 [PATCH V3 0/6] RCU get_user_pages_fast and __get_user_pages_fast Steve Capper
2014-08-28 14:45 ` Steve Capper
2014-08-28 14:45 ` [PATCH V3 1/6] mm: Introduce a general RCU get_user_pages_fast Steve Capper
2014-08-28 14:45   ` Steve Capper
2014-09-24 13:34   ` Hugh Dickins
2014-09-24 13:34     ` Hugh Dickins
2014-09-24 15:57     ` Steve Capper
2014-09-24 15:57       ` Steve Capper
2014-08-28 14:45 ` [PATCH V3 2/6] arm: mm: Introduce special ptes for LPAE Steve Capper
2014-08-28 14:45   ` Steve Capper
2014-08-28 14:45 ` [PATCH V3 3/6] arm: mm: Enable HAVE_RCU_TABLE_FREE logic Steve Capper
2014-08-28 14:45   ` Steve Capper
2014-08-28 14:45 ` [PATCH V3 4/6] arm: mm: Enable RCU fast_gup Steve Capper
2014-08-28 14:45 ` [PATCH V3 5/6] arm64: mm: Enable HAVE_RCU_TABLE_FREE logic Steve Capper
2014-08-28 14:45   ` Steve Capper
2014-08-28 14:45 ` Steve Capper [this message]
2014-08-28 14:45   ` [PATCH V3 6/6] arm64: mm: Enable RCU fast_gup Steve Capper
2014-08-28 15:23 ` [PATCH V3 0/6] RCU get_user_pages_fast and __get_user_pages_fast Will Deacon
2014-09-01 11:43   ` Steve Capper
2014-09-01 11:43     ` Steve Capper
2014-09-08  9:06     ` Steve Capper
2014-09-08  9:06       ` Steve Capper
2014-09-19 18:28       ` Steve Capper
2014-09-19 18:28         ` Steve Capper
2014-09-22  9:28         ` Will Deacon

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