[PATCH v2 00/12] THP support for ARC

[PATCH v2 00/12] THP support for ARC

[Vineet Gupta]

Hi,

This series brings THP support to ARC. It also introduces an optional new
thp hook for arches to possibly optimize the TLB flush in thp regime.

Please review !

Changes Since v1 [*]
   - Rebased against v4.3-rc2
   - Switched ARC pgtable_t to pte_t * 		(Kiril)
   - Removed stub implementations for		(Andrew)
	pmdp_set_access_flags, pmdp_test_and_clear_young, pmdp_set_wrprotect,
	pmdp_collapse_flush, pmd_same

[*] http://lkml.kernel.org/r/1440666194-21478-1-git-send-email-vgupta@synopsys.com

Vineet Gupta (12):
  ARC: mm: switch pgtable_to to pte_t *
  ARC: mm: pte flags comsetic cleanups, comments
  ARC: mm: Introduce PTE_SPECIAL
  Documentation/features/vm: pte_special now supported by ARC
  ARCv2: mm: THP support
  ARCv2: mm: THP: boot validation/reporting
  Documentation/features/vm: THP now supported by ARC
  mm: move some code around
  mm,thp: reduce ifdef'ery for THP in generic code
  mm,thp: introduce flush_pmd_tlb_range
  ARCv2: mm: THP: Implement flush_pmd_tlb_range() optimization
  ARCv2: Add a DT which enables THP

 Documentation/features/vm/THP/arch-support.txt     |  2 +-
 .../features/vm/pte_special/arch-support.txt       |  2 +-
 arch/arc/Kconfig                                   |  4 +
 arch/arc/boot/dts/hs_thp.dts                       | 59 +++++++++++++
 arch/arc/include/asm/hugepage.h                    | 82 ++++++++++++++++++
 arch/arc/include/asm/page.h                        |  5 +-
 arch/arc/include/asm/pgalloc.h                     |  6 +-
 arch/arc/include/asm/pgtable.h                     | 60 +++++++------
 arch/arc/mm/tlb.c                                  | 76 ++++++++++++++++-
 arch/arc/mm/tlbex.S                                | 21 +++--
 include/asm-generic/pgtable.h                      | 49 ++++-------
 mm/huge_memory.c                                   |  2 +-
 mm/pgtable-generic.c                               | 99 ++++++++++------------
 13 files changed, 345 insertions(+), 122 deletions(-)
 create mode 100644 arch/arc/boot/dts/hs_thp.dts
 create mode 100644 arch/arc/include/asm/hugepage.h

-- 
1.9.1

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[PATCH v2 01/12] ARC: mm: switch pgtable_to to pte_t *

[Vineet Gupta]

ARC is the only arch with unsigned long type (vs. struct page *).
Historically this was done to avoid the page_address() calls in various
arch hooks which need to get the virtual/logical address of the table.

Some arches alternately define it as pte_t *, and is as efficient as
unsigned long (generated code doesn't change)

Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/include/asm/page.h    | 4 ++--
 arch/arc/include/asm/pgalloc.h | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index 9c8aa41e45c2..2994cac1069e 100644
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -43,7 +43,6 @@ typedef struct {
 typedef struct {
 	unsigned long pgprot;
 } pgprot_t;
-typedef unsigned long pgtable_t;
 
 #define pte_val(x)      ((x).pte)
 #define pgd_val(x)      ((x).pgd)
@@ -60,7 +59,6 @@ typedef unsigned long pgtable_t;
 typedef unsigned long pte_t;
 typedef unsigned long pgd_t;
 typedef unsigned long pgprot_t;
-typedef unsigned long pgtable_t;
 
 #define pte_val(x)	(x)
 #define pgd_val(x)	(x)
@@ -71,6 +69,8 @@ typedef unsigned long pgtable_t;
 
 #endif
 
+typedef pte_t * pgtable_t;
+
 #define ARCH_PFN_OFFSET     (CONFIG_LINUX_LINK_BASE >> PAGE_SHIFT)
 
 #define pfn_valid(pfn)      (((pfn) - ARCH_PFN_OFFSET) < max_mapnr)
diff --git a/arch/arc/include/asm/pgalloc.h b/arch/arc/include/asm/pgalloc.h
index 81208bfd9dcb..9149b5ca26d7 100644
--- a/arch/arc/include/asm/pgalloc.h
+++ b/arch/arc/include/asm/pgalloc.h
@@ -107,7 +107,7 @@ pte_alloc_one(struct mm_struct *mm, unsigned long address)
 	pgtable_t pte_pg;
 	struct page *page;
 
-	pte_pg = __get_free_pages(GFP_KERNEL | __GFP_REPEAT, __get_order_pte());
+	pte_pg = (pgtable_t)__get_free_pages(GFP_KERNEL | __GFP_REPEAT, __get_order_pte());
 	if (!pte_pg)
 		return 0;
 	memzero((void *)pte_pg, PTRS_PER_PTE * 4);
@@ -128,12 +128,12 @@ static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
 static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)
 {
 	pgtable_page_dtor(virt_to_page(ptep));
-	free_pages(ptep, __get_order_pte());
+	free_pages((unsigned long)ptep, __get_order_pte());
 }
 
 #define __pte_free_tlb(tlb, pte, addr)  pte_free((tlb)->mm, pte)
 
 #define check_pgt_cache()   do { } while (0)
-#define pmd_pgtable(pmd) pmd_page_vaddr(pmd)
+#define pmd_pgtable(pmd)	((pgtable_t) pmd_page_vaddr(pmd))
 
 #endif /* _ASM_ARC_PGALLOC_H */
-- 
1.9.1

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[PATCH v2 02/12] ARC: mm: pte flags comsetic cleanups, comments

[Vineet Gupta]

No semantical changes

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/include/asm/pgtable.h | 37 ++++++++++++++++---------------------
 arch/arc/mm/tlbex.S            |  2 +-
 2 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 1281718802f7..481359fe56ae 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -60,7 +60,7 @@
 #define _PAGE_EXECUTE       (1<<3)	/* Page has user execute perm (H) */
 #define _PAGE_WRITE         (1<<4)	/* Page has user write perm (H) */
 #define _PAGE_READ          (1<<5)	/* Page has user read perm (H) */
-#define _PAGE_MODIFIED      (1<<6)	/* Page modified (dirty) (S) */
+#define _PAGE_DIRTY         (1<<6)	/* Page modified (dirty) (S) */
 #define _PAGE_GLOBAL        (1<<8)	/* Page is global (H) */
 #define _PAGE_PRESENT       (1<<10)	/* TLB entry is valid (H) */
 
@@ -71,7 +71,7 @@
 #define _PAGE_WRITE         (1<<2)	/* Page has user write perm (H) */
 #define _PAGE_READ          (1<<3)	/* Page has user read perm (H) */
 #define _PAGE_ACCESSED      (1<<4)	/* Page is accessed (S) */
-#define _PAGE_MODIFIED      (1<<5)	/* Page modified (dirty) (S) */
+#define _PAGE_DIRTY         (1<<5)	/* Page modified (dirty) (S) */
 
 #if (CONFIG_ARC_MMU_VER >= 4)
 #define _PAGE_WTHRU         (1<<7)	/* Page cache mode write-thru (H) */
@@ -92,21 +92,16 @@
 #define _K_PAGE_PERMS  (_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ | \
 			_PAGE_GLOBAL | _PAGE_PRESENT)
 
-#ifdef CONFIG_ARC_CACHE_PAGES
-#define _PAGE_DEF_CACHEABLE _PAGE_CACHEABLE
-#else
-#define _PAGE_DEF_CACHEABLE (0)
+#ifndef CONFIG_ARC_CACHE_PAGES
+#undef _PAGE_CACHEABLE
+#define _PAGE_CACHEABLE 0
 #endif
 
-/* Helper for every "user" page
- * -kernel can R/W/X
- * -by default cached, unless config otherwise
- * -present in memory
- */
-#define ___DEF (_PAGE_PRESENT | _PAGE_DEF_CACHEABLE)
+/* Defaults for every user page */
+#define ___DEF (_PAGE_PRESENT | _PAGE_CACHEABLE)
 
 /* Set of bits not changed in pte_modify */
-#define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_MODIFIED)
+#define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY)
 
 /* More Abbrevaited helpers */
 #define PAGE_U_NONE     __pgprot(___DEF)
@@ -122,7 +117,7 @@
  * user vaddr space - visible in all addr spaces, but kernel mode only
  * Thus Global, all-kernel-access, no-user-access, cached
  */
-#define PAGE_KERNEL          __pgprot(_K_PAGE_PERMS | _PAGE_DEF_CACHEABLE)
+#define PAGE_KERNEL          __pgprot(_K_PAGE_PERMS | _PAGE_CACHEABLE)
 
 /* ioremap */
 #define PAGE_KERNEL_NO_CACHE __pgprot(_K_PAGE_PERMS)
@@ -191,16 +186,16 @@
 
 /* Optimal Sizing of Pg Tbl - based on MMU page size */
 #if defined(CONFIG_ARC_PAGE_SIZE_8K)
-#define BITS_FOR_PTE	8
+#define BITS_FOR_PTE	8		/* 11:8:13 */
 #elif defined(CONFIG_ARC_PAGE_SIZE_16K)
-#define BITS_FOR_PTE	8
+#define BITS_FOR_PTE	8		/* 10:8:14 */
 #elif defined(CONFIG_ARC_PAGE_SIZE_4K)
-#define BITS_FOR_PTE	9
+#define BITS_FOR_PTE	9		/* 11:9:12 */
 #endif
 
 #define BITS_FOR_PGD	(32 - BITS_FOR_PTE - BITS_IN_PAGE)
 
-#define PGDIR_SHIFT	(BITS_FOR_PTE + BITS_IN_PAGE)
+#define PGDIR_SHIFT	(32 - BITS_FOR_PGD)
 #define PGDIR_SIZE	(1UL << PGDIR_SHIFT)	/* vaddr span, not PDG sz */
 #define PGDIR_MASK	(~(PGDIR_SIZE-1))
 
@@ -295,7 +290,7 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
 /* Zoo of pte_xxx function */
 #define pte_read(pte)		(pte_val(pte) & _PAGE_READ)
 #define pte_write(pte)		(pte_val(pte) & _PAGE_WRITE)
-#define pte_dirty(pte)		(pte_val(pte) & _PAGE_MODIFIED)
+#define pte_dirty(pte)		(pte_val(pte) & _PAGE_DIRTY)
 #define pte_young(pte)		(pte_val(pte) & _PAGE_ACCESSED)
 #define pte_special(pte)	(0)
 
@@ -304,8 +299,8 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
 
 PTE_BIT_FUNC(wrprotect,	&= ~(_PAGE_WRITE));
 PTE_BIT_FUNC(mkwrite,	|= (_PAGE_WRITE));
-PTE_BIT_FUNC(mkclean,	&= ~(_PAGE_MODIFIED));
-PTE_BIT_FUNC(mkdirty,	|= (_PAGE_MODIFIED));
+PTE_BIT_FUNC(mkclean,	&= ~(_PAGE_DIRTY));
+PTE_BIT_FUNC(mkdirty,	|= (_PAGE_DIRTY));
 PTE_BIT_FUNC(mkold,	&= ~(_PAGE_ACCESSED));
 PTE_BIT_FUNC(mkyoung,	|= (_PAGE_ACCESSED));
 PTE_BIT_FUNC(exprotect,	&= ~(_PAGE_EXECUTE));
diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S
index f6f4c3cb505d..b8b014c6904d 100644
--- a/arch/arc/mm/tlbex.S
+++ b/arch/arc/mm/tlbex.S
@@ -365,7 +365,7 @@ ENTRY(EV_TLBMissD)
 	lr      r3, [ecr]
 	or      r0, r0, _PAGE_ACCESSED        ; Accessed bit always
 	btst_s  r3,  ECR_C_BIT_DTLB_ST_MISS   ; See if it was a Write Access ?
-	or.nz   r0, r0, _PAGE_MODIFIED        ; if Write, set Dirty bit as well
+	or.nz   r0, r0, _PAGE_DIRTY           ; if Write, set Dirty bit as well
 	st_s    r0, [r1]                      ; Write back PTE
 
 	CONV_PTE_TO_TLB
-- 
1.9.1

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[PATCH v2 03/12] ARC: mm: Introduce PTE_SPECIAL

[Vineet Gupta]

Needed for THP, but will also come in handy for fast GUP later

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/include/asm/pgtable.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 481359fe56ae..431a83329324 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -61,6 +61,7 @@
 #define _PAGE_WRITE         (1<<4)	/* Page has user write perm (H) */
 #define _PAGE_READ          (1<<5)	/* Page has user read perm (H) */
 #define _PAGE_DIRTY         (1<<6)	/* Page modified (dirty) (S) */
+#define _PAGE_SPECIAL       (1<<7)
 #define _PAGE_GLOBAL        (1<<8)	/* Page is global (H) */
 #define _PAGE_PRESENT       (1<<10)	/* TLB entry is valid (H) */
 
@@ -72,6 +73,7 @@
 #define _PAGE_READ          (1<<3)	/* Page has user read perm (H) */
 #define _PAGE_ACCESSED      (1<<4)	/* Page is accessed (S) */
 #define _PAGE_DIRTY         (1<<5)	/* Page modified (dirty) (S) */
+#define _PAGE_SPECIAL       (1<<6)
 
 #if (CONFIG_ARC_MMU_VER >= 4)
 #define _PAGE_WTHRU         (1<<7)	/* Page cache mode write-thru (H) */
@@ -292,7 +294,7 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
 #define pte_write(pte)		(pte_val(pte) & _PAGE_WRITE)
 #define pte_dirty(pte)		(pte_val(pte) & _PAGE_DIRTY)
 #define pte_young(pte)		(pte_val(pte) & _PAGE_ACCESSED)
-#define pte_special(pte)	(0)
+#define pte_special(pte)	(pte_val(pte) & _PAGE_SPECIAL)
 
 #define PTE_BIT_FUNC(fn, op) \
 	static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
@@ -305,8 +307,9 @@ PTE_BIT_FUNC(mkold,	&= ~(_PAGE_ACCESSED));
 PTE_BIT_FUNC(mkyoung,	|= (_PAGE_ACCESSED));
 PTE_BIT_FUNC(exprotect,	&= ~(_PAGE_EXECUTE));
 PTE_BIT_FUNC(mkexec,	|= (_PAGE_EXECUTE));
+PTE_BIT_FUNC(mkspecial,	|= (_PAGE_SPECIAL));
 
-static inline pte_t pte_mkspecial(pte_t pte) { return pte; }
+#define __HAVE_ARCH_PTE_SPECIAL
 
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
-- 
1.9.1

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[PATCH v2 04/12] Documentation/features/vm: pte_special now supported by ARC

[Vineet Gupta]

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 Documentation/features/vm/pte_special/arch-support.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/features/vm/pte_special/arch-support.txt b/Documentation/features/vm/pte_special/arch-support.txt
index aaaa21db6226..3de5434c857c 100644
--- a/Documentation/features/vm/pte_special/arch-support.txt
+++ b/Documentation/features/vm/pte_special/arch-support.txt
@@ -7,7 +7,7 @@
     |         arch |status|
     -----------------------
     |       alpha: | TODO |
-    |         arc: | TODO |
+    |         arc: |  ok  |
     |         arm: |  ok  |
     |       arm64: |  ok  |
     |       avr32: | TODO |
-- 
1.9.1

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[PATCH v2 05/12] ARCv2: mm: THP support

[Vineet Gupta]

ARC Linux implements 2 level page walk: PGD:PTE
In THP regime, PTE is folded into PGD (and canonically referred to as PMD)
Thus thp PMD accessors are implemented in terms of PTE (just like sparc)

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/Kconfig                |  4 +++
 arch/arc/include/asm/hugepage.h | 78 +++++++++++++++++++++++++++++++++++++++++
 arch/arc/include/asm/page.h     |  1 +
 arch/arc/include/asm/pgtable.h  | 16 +++++++--
 arch/arc/mm/tlb.c               | 48 +++++++++++++++++++++++++
 arch/arc/mm/tlbex.S             | 19 +++++++---
 6 files changed, 160 insertions(+), 6 deletions(-)
 create mode 100644 arch/arc/include/asm/hugepage.h

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 78c0621d5819..5912006391ed 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -76,6 +76,10 @@ config STACKTRACE_SUPPORT
 config HAVE_LATENCYTOP_SUPPORT
 	def_bool y
 
+config HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	def_bool y
+	depends on ARC_MMU_V4
+
 source "init/Kconfig"
 source "kernel/Kconfig.freezer"
 
diff --git a/arch/arc/include/asm/hugepage.h b/arch/arc/include/asm/hugepage.h
new file mode 100644
index 000000000000..d7614d2af454
--- /dev/null
+++ b/arch/arc/include/asm/hugepage.h
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2013-15 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+
+#ifndef _ASM_ARC_HUGEPAGE_H
+#define _ASM_ARC_HUGEPAGE_H
+
+#include <linux/types.h>
+#include <asm-generic/pgtable-nopmd.h>
+
+/*
+ * ARC Linux implements 2 level page walk: PGD:PTE
+ * In THP regime, PTE is folded into PGD (and canonically referred to as PMD)
+ * Thus thp PMD accessors are implemented in terms of PTE (just like sparc)
+ */
+static inline pte_t pmd_pte(pmd_t pmd)
+{
+	return __pte(pmd_val(pmd));
+}
+
+static inline pmd_t pte_pmd(pte_t pte)
+{
+	return __pmd(pte_val(pte));
+}
+
+#define pmd_wrprotect(pmd)	pte_pmd(pte_wrprotect(pmd_pte(pmd)))
+#define pmd_mkwrite(pmd)	pte_pmd(pte_mkwrite(pmd_pte(pmd)))
+#define pmd_mkdirty(pmd)	pte_pmd(pte_mkdirty(pmd_pte(pmd)))
+#define pmd_mkold(pmd)		pte_pmd(pte_mkold(pmd_pte(pmd)))
+#define pmd_mkyoung(pmd)	pte_pmd(pte_mkyoung(pmd_pte(pmd)))
+#define pmd_mkhuge(pmd)		pte_pmd(pte_mkhuge(pmd_pte(pmd)))
+#define pmd_mknotpresent(pmd)	pte_pmd(pte_mknotpresent(pmd_pte(pmd)))
+#define pmd_mksplitting(pmd)	pte_pmd(pte_mkspecial(pmd_pte(pmd)))
+#define pmd_mkclean(pmd)	pte_pmd(pte_mkclean(pmd_pte(pmd)))
+
+#define pmd_write(pmd)		pte_write(pmd_pte(pmd))
+#define pmd_young(pmd)		pte_young(pmd_pte(pmd))
+#define pmd_pfn(pmd)		pte_pfn(pmd_pte(pmd))
+#define pmd_dirty(pmd)		pte_dirty(pmd_pte(pmd))
+#define pmd_special(pmd)	pte_special(pmd_pte(pmd))
+
+#define mk_pmd(page, prot)	pte_pmd(mk_pte(page, prot))
+
+#define pmd_trans_huge(pmd)	(pmd_val(pmd) & _PAGE_HW_SZ)
+#define pmd_trans_splitting(pmd)	(pmd_trans_huge(pmd) && pmd_special(pmd))
+
+#define pfn_pmd(pfn, prot)	(__pmd(((pfn) << PAGE_SHIFT) | pgprot_val(prot)))
+
+static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
+{
+	return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
+}
+
+static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
+			      pmd_t *pmdp, pmd_t pmd)
+{
+	*pmdp = pmd;
+}
+
+extern void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
+				 pmd_t *pmd);
+
+#define has_transparent_hugepage() 1
+
+/* Generic variants assume pgtable_t is struct page *, hence need for these */
+#define __HAVE_ARCH_PGTABLE_DEPOSIT
+extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				       pgtable_t pgtable);
+
+#define __HAVE_ARCH_PGTABLE_WITHDRAW
+extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
+
+#endif
diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index 2994cac1069e..37706837ef75 100644
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -64,6 +64,7 @@ typedef unsigned long pgprot_t;
 #define pgd_val(x)	(x)
 #define pgprot_val(x)	(x)
 #define __pte(x)	(x)
+#define __pgd(x)	(x)
 #define __pgprot(x)	(x)
 #define pte_pgprot(x)	(x)
 
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 431a83329324..336267f2e9d9 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -83,11 +83,13 @@
 #define _PAGE_PRESENT       (1<<9)	/* TLB entry is valid (H) */
 
 #if (CONFIG_ARC_MMU_VER >= 4)
-#define _PAGE_SZ            (1<<10)	/* Page Size indicator (H) */
+#define _PAGE_HW_SZ         (1<<10)	/* Page Size indicator (H): 0 normal, 1 super */
 #endif
 
 #define _PAGE_SHARED_CODE   (1<<11)	/* Shared Code page with cmn vaddr
 					   usable for shared TLB entries (H) */
+
+#define _PAGE_UNUSED_BIT    (1<<12)
 #endif
 
 /* vmalloc permissions */
@@ -99,6 +101,10 @@
 #define _PAGE_CACHEABLE 0
 #endif
 
+#ifndef _PAGE_HW_SZ
+#define _PAGE_HW_SZ	0
+#endif
+
 /* Defaults for every user page */
 #define ___DEF (_PAGE_PRESENT | _PAGE_CACHEABLE)
 
@@ -125,7 +131,7 @@
 #define PAGE_KERNEL_NO_CACHE __pgprot(_K_PAGE_PERMS)
 
 /* Masks for actual TLB "PD"s */
-#define PTE_BITS_IN_PD0		(_PAGE_GLOBAL | _PAGE_PRESENT)
+#define PTE_BITS_IN_PD0		(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_HW_SZ)
 #define PTE_BITS_RWX		(_PAGE_EXECUTE | _PAGE_WRITE | _PAGE_READ)
 #define PTE_BITS_NON_RWX_IN_PD1	(PAGE_MASK | _PAGE_CACHEABLE)
 
@@ -299,6 +305,7 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep)
 #define PTE_BIT_FUNC(fn, op) \
 	static inline pte_t pte_##fn(pte_t pte) { pte_val(pte) op; return pte; }
 
+PTE_BIT_FUNC(mknotpresent,	&= ~(_PAGE_PRESENT));
 PTE_BIT_FUNC(wrprotect,	&= ~(_PAGE_WRITE));
 PTE_BIT_FUNC(mkwrite,	|= (_PAGE_WRITE));
 PTE_BIT_FUNC(mkclean,	&= ~(_PAGE_DIRTY));
@@ -308,6 +315,7 @@ PTE_BIT_FUNC(mkyoung,	|= (_PAGE_ACCESSED));
 PTE_BIT_FUNC(exprotect,	&= ~(_PAGE_EXECUTE));
 PTE_BIT_FUNC(mkexec,	|= (_PAGE_EXECUTE));
 PTE_BIT_FUNC(mkspecial,	|= (_PAGE_SPECIAL));
+PTE_BIT_FUNC(mkhuge,	|= (_PAGE_HW_SZ));
 
 #define __HAVE_ARCH_PTE_SPECIAL
 
@@ -381,6 +389,10 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
  * remap a physical page `pfn' of size `size' with page protection `prot'
  * into virtual address `from'
  */
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#include <asm/hugepage.h>
+#endif
+
 #include <asm-generic/pgtable.h>
 
 /* to cope with aliasing VIPT cache */
diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index 2c7ce8bb7475..62da703a1681 100644
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -580,6 +580,54 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long vaddr_unaligned,
 	}
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
+void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
+				 pmd_t *pmd)
+{
+	pte_t pte = __pte(pmd_val(*pmd));
+	update_mmu_cache(vma, addr, &pte);
+}
+
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+				pgtable_t pgtable)
+{
+	struct list_head *lh = (struct list_head *) pgtable;
+
+	assert_spin_locked(&mm->page_table_lock);
+
+	/* FIFO */
+	if (!pmd_huge_pte(mm, pmdp))
+		INIT_LIST_HEAD(lh);
+	else
+		list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
+	pmd_huge_pte(mm, pmdp) = pgtable;
+}
+
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
+{
+	struct list_head *lh;
+	pgtable_t pgtable;
+
+	assert_spin_locked(&mm->page_table_lock);
+
+	pgtable = pmd_huge_pte(mm, pmdp);
+	lh = (struct list_head *) pgtable;
+	if (list_empty(lh))
+		pmd_huge_pte(mm, pmdp) = NULL;
+	else {
+		pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
+		list_del(lh);
+	}
+
+	pte_val(pgtable[0]) = 0;
+	pte_val(pgtable[1]) = 0;
+
+	return pgtable;
+}
+
+#endif
+
 /* Read the Cache Build Confuration Registers, Decode them and save into
  * the cpuinfo structure for later use.
  * No Validation is done here, simply read/convert the BCRs
diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S
index b8b014c6904d..552594897655 100644
--- a/arch/arc/mm/tlbex.S
+++ b/arch/arc/mm/tlbex.S
@@ -205,10 +205,18 @@ ex_saved_reg1:
 #endif
 
 	lsr     r0, r2, PGDIR_SHIFT     ; Bits for indexing into PGD
-	ld.as   r1, [r1, r0]            ; PGD entry corresp to faulting addr
-	and.f   r1, r1, PAGE_MASK       ; Ignoring protection and other flags
-	;   contains Ptr to Page Table
-	bz.d    do_slow_path_pf         ; if no Page Table, do page fault
+	ld.as   r3, [r1, r0]            ; PGD entry corresp to faulting addr
+	tst	r3, r3
+	bz	do_slow_path_pf         ; if no Page Table, do page fault
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	and.f	0, r3, _PAGE_HW_SZ	; Is this Huge PMD (thp)
+	add2.nz	r1, r1, r0
+	bnz.d	2f		; YES: PGD == PMD has THP PTE: stop pgd walk
+	mov.nz	r0, r3
+
+#endif
+	and	r1, r3, PAGE_MASK
 
 	; Get the PTE entry: The idea is
 	; (1) x = addr >> PAGE_SHIFT 	-> masks page-off bits from @fault-addr
@@ -219,6 +227,9 @@ ex_saved_reg1:
 	lsr     r0, r2, (PAGE_SHIFT - 2)
 	and     r0, r0, ( (PTRS_PER_PTE - 1) << 2)
 	ld.aw   r0, [r1, r0]            ; get PTE and PTE ptr for fault addr
+
+2:
+
 #ifdef CONFIG_ARC_DBG_TLB_MISS_COUNT
 	and.f 0, r0, _PAGE_PRESENT
 	bz   1f
-- 
1.9.1

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[PATCH v2 06/12] ARCv2: mm: THP: boot validation/reporting

[Vineet Gupta]

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/mm/tlb.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index 62da703a1681..80e28555a5de 100644
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -703,7 +703,8 @@ char *arc_mmu_mumbojumbo(int cpu_id, char *buf, int len)
 
 	if (p_mmu->s_pg_sz_m)
 		scnprintf(super_pg, 64, "%dM Super Page%s, ",
-			  p_mmu->s_pg_sz_m, " (not used)");
+			  p_mmu->s_pg_sz_m,
+			  IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) ? "" : " (not used)");
 
 	n += scnprintf(buf + n, len - n,
 		      "MMU [v%x]\t: %dk PAGE, %sJTLB %d (%dx%d), uDTLB %d, uITLB %d %s\n",
@@ -738,6 +739,11 @@ void arc_mmu_init(void)
 	if (mmu->pg_sz_k != TO_KB(PAGE_SIZE))
 		panic("MMU pg size != PAGE_SIZE (%luk)\n", TO_KB(PAGE_SIZE));
 
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+	    mmu->s_pg_sz_m != TO_MB(HPAGE_PMD_SIZE))
+		panic("MMU Super pg size != Linux HPAGE_PMD_SIZE (%luM)\n",
+		      (unsigned long)TO_MB(HPAGE_PMD_SIZE));
+
 	/* Enable the MMU */
 	write_aux_reg(ARC_REG_PID, MMU_ENABLE);
 
-- 
1.9.1

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[PATCH v2 07/12] Documentation/features/vm: THP now supported by ARC

[Vineet Gupta]

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 Documentation/features/vm/THP/arch-support.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/features/vm/THP/arch-support.txt b/Documentation/features/vm/THP/arch-support.txt
index df384e3e845f..523f8307b9cd 100644
--- a/Documentation/features/vm/THP/arch-support.txt
+++ b/Documentation/features/vm/THP/arch-support.txt
@@ -7,7 +7,7 @@
     |         arch |status|
     -----------------------
     |       alpha: | TODO |
-    |         arc: |  ..  |
+    |         arc: |  ok  |
     |         arm: |  ok  |
     |       arm64: |  ok  |
     |       avr32: |  ..  |
-- 
1.9.1

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[PATCH v2 08/12] mm: move some code around

[Vineet Gupta]

This reduces/simplifies the diff for the next patch which moves THP
specific code.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 mm/pgtable-generic.c | 50 +++++++++++++++++++++++++-------------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 6b674e00153c..48851894e699 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -57,6 +57,31 @@ int ptep_set_access_flags(struct vm_area_struct *vma,
 }
 #endif
 
+#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
+int ptep_clear_flush_young(struct vm_area_struct *vma,
+			   unsigned long address, pte_t *ptep)
+{
+	int young;
+	young = ptep_test_and_clear_young(vma, address, ptep);
+	if (young)
+		flush_tlb_page(vma, address);
+	return young;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
+pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
+		       pte_t *ptep)
+{
+	struct mm_struct *mm = (vma)->vm_mm;
+	pte_t pte;
+	pte = ptep_get_and_clear(mm, address, ptep);
+	if (pte_accessible(mm, pte))
+		flush_tlb_page(vma, address);
+	return pte;
+}
+#endif
+
 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 int pmdp_set_access_flags(struct vm_area_struct *vma,
 			  unsigned long address, pmd_t *pmdp,
@@ -77,18 +102,6 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
 }
 #endif
 
-#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
-int ptep_clear_flush_young(struct vm_area_struct *vma,
-			   unsigned long address, pte_t *ptep)
-{
-	int young;
-	young = ptep_test_and_clear_young(vma, address, ptep);
-	if (young)
-		flush_tlb_page(vma, address);
-	return young;
-}
-#endif
-
 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 int pmdp_clear_flush_young(struct vm_area_struct *vma,
 			   unsigned long address, pmd_t *pmdp)
@@ -106,19 +119,6 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
 }
 #endif
 
-#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
-pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
-		       pte_t *ptep)
-{
-	struct mm_struct *mm = (vma)->vm_mm;
-	pte_t pte;
-	pte = ptep_get_and_clear(mm, address, ptep);
-	if (pte_accessible(mm, pte))
-		flush_tlb_page(vma, address);
-	return pte;
-}
-#endif
-
 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
-- 
1.9.1

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[PATCH v2 09/12] mm,thp: reduce ifdef'ery for THP in generic code

[Vineet Gupta]

- pgtable-generic.c: Fold individual #ifdef for each helper into a top
  level #ifdef. Makes code more readable

- Per Andrew's suggestion removed the dummy implementations for !THP
  in asm-generic/page-table.h to have build time failures vs. runtime.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 include/asm-generic/pgtable.h | 49 ++++++++++++++++---------------------------
 mm/pgtable-generic.c          | 24 +++------------------
 2 files changed, 21 insertions(+), 52 deletions(-)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 29c57b2cb344..2112f4147816 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -30,9 +30,12 @@ extern int ptep_set_access_flags(struct vm_area_struct *vma,
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 extern int pmdp_set_access_flags(struct vm_area_struct *vma,
 				 unsigned long address, pmd_t *pmdp,
 				 pmd_t entry, int dirty);
+
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
@@ -64,14 +67,6 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
 		set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
 	return r;
 }
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
-static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
-					    unsigned long address,
-					    pmd_t *pmdp)
-{
-	BUG();
-	return 0;
-}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
@@ -81,8 +76,21 @@ int ptep_clear_flush_young(struct vm_area_struct *vma,
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
-int pmdp_clear_flush_young(struct vm_area_struct *vma,
-			   unsigned long address, pmd_t *pmdp);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
+				  unsigned long address, pmd_t *pmdp);
+#else
+/*
+ * Despite relevant to THP only, this API is called from generic rmap code
+ * under PageTransHuge(), hence needs a dummy implementation for !THP
+ */
+static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
+					 unsigned long address, pmd_t *pmdp)
+{
+	BUG();
+	return 0;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
@@ -175,12 +183,6 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 	pmd_t old_pmd = *pmdp;
 	set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd));
 }
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
-static inline void pmdp_set_wrprotect(struct mm_struct *mm,
-				      unsigned long address, pmd_t *pmdp)
-{
-	BUG();
-}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
@@ -193,15 +195,6 @@ extern void pmdp_splitting_flush(struct vm_area_struct *vma,
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 				 unsigned long address, pmd_t *pmdp);
-#else
-static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
-					unsigned long address,
-					pmd_t *pmdp)
-{
-	BUILD_BUG();
-	return *pmdp;
-}
-#define pmdp_collapse_flush pmdp_collapse_flush
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
@@ -245,12 +238,6 @@ static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
 {
 	return pmd_val(pmd_a) == pmd_val(pmd_b);
 }
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
-static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b)
-{
-	BUG();
-	return 0;
-}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 48851894e699..c9c59bb75a17 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -82,12 +82,13 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
 }
 #endif
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 int pmdp_set_access_flags(struct vm_area_struct *vma,
 			  unsigned long address, pmd_t *pmdp,
 			  pmd_t entry, int dirty)
 {
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	int changed = !pmd_same(*pmdp, entry);
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	if (changed) {
@@ -95,10 +96,6 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
 		flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 	}
 	return changed;
-#else /* CONFIG_TRANSPARENT_HUGEPAGE */
-	BUG();
-	return 0;
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 }
 #endif
 
@@ -107,11 +104,7 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
 			   unsigned long address, pmd_t *pmdp)
 {
 	int young;
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
-#else
-	BUG();
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 	young = pmdp_test_and_clear_young(vma, address, pmdp);
 	if (young)
 		flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
@@ -120,7 +113,6 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 			    pmd_t *pmdp)
 {
@@ -131,11 +123,9 @@ pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 	return pmd;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 			  pmd_t *pmdp)
 {
@@ -145,11 +135,9 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 	/* tlb flush only to serialize against gup-fast */
 	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 				pgtable_t pgtable)
 {
@@ -162,11 +150,9 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 		list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
 	pmd_huge_pte(mm, pmdp) = pgtable;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 /* no "address" argument so destroys page coloring of some arch */
 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 {
@@ -185,11 +171,9 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 	}
 	return pgtable;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 		     pmd_t *pmdp)
 {
@@ -197,11 +181,9 @@ void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 	set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(entry));
 	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
 #ifndef pmdp_collapse_flush
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 			  pmd_t *pmdp)
 {
@@ -217,5 +199,5 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 	return pmd;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-- 
1.9.1

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[PATCH v2 10/12] mm,thp: introduce flush_pmd_tlb_range

[Vineet Gupta]

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 mm/huge_memory.c     |  2 +-
 mm/pgtable-generic.c | 25 +++++++++++++++++++------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4b06b8db9df2..e25eb3d2081a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1880,7 +1880,7 @@ static int __split_huge_page_map(struct page *page,
 		 * here). But it is generally safer to never allow
 		 * small and huge TLB entries for the same virtual
 		 * address to be loaded simultaneously. So instead of
-		 * doing "pmd_populate(); flush_tlb_range();" we first
+		 * doing "pmd_populate(); flush_pmd_tlb_range();" we first
 		 * mark the current pmd notpresent (atomically because
 		 * here the pmd_trans_huge and pmd_trans_splitting
 		 * must remain set at all times on the pmd until the
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index c9c59bb75a17..b0fed9a4776e 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -84,6 +84,19 @@ pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 
+#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
+
+/*
+ * ARCHes with special requirements for evicting THP backing TLB entries can
+ * implement this. Otherwise also, it can help optimizing thp flush operation.
+ * flush_tlb_range() can have optimization to nuke the entire TLB if flush span
+ * is greater than a threashhold, which will likely be true for a single
+ * huge page.
+ * e.g. see arch/arc: flush_pmd_tlb_range
+ */
+#define flush_pmd_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
+#endif
+
 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 int pmdp_set_access_flags(struct vm_area_struct *vma,
 			  unsigned long address, pmd_t *pmdp,
@@ -93,7 +106,7 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	if (changed) {
 		set_pmd_at(vma->vm_mm, address, pmdp, entry);
-		flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+		flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 	}
 	return changed;
 }
@@ -107,7 +120,7 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	young = pmdp_test_and_clear_young(vma, address, pmdp);
 	if (young)
-		flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+		flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 	return young;
 }
 #endif
@@ -120,7 +133,7 @@ pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	VM_BUG_ON(!pmd_trans_huge(*pmdp));
 	pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
-	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+	flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 	return pmd;
 }
 #endif
@@ -133,7 +146,7 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	set_pmd_at(vma->vm_mm, address, pmdp, pmd);
 	/* tlb flush only to serialize against gup-fast */
-	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+	flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 }
 #endif
 
@@ -179,7 +192,7 @@ void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 {
 	pmd_t entry = *pmdp;
 	set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(entry));
-	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+	flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 }
 #endif
 
@@ -196,7 +209,7 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 	VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 	VM_BUG_ON(pmd_trans_huge(*pmdp));
 	pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
-	flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+	flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 	return pmd;
 }
 #endif
-- 
1.9.1

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[PATCH v2 11/12] ARCv2: mm: THP: Implement flush_pmd_tlb_range() optimization

[Vineet Gupta]

Implement the TLB flush routine to evict a sepcific Super TLB entry,
vs. moving to a new ASID on every such flush.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/include/asm/hugepage.h |  4 ++++
 arch/arc/mm/tlb.c               | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/arch/arc/include/asm/hugepage.h b/arch/arc/include/asm/hugepage.h
index d7614d2af454..bf74f507e038 100644
--- a/arch/arc/include/asm/hugepage.h
+++ b/arch/arc/include/asm/hugepage.h
@@ -75,4 +75,8 @@ extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 #define __HAVE_ARCH_PGTABLE_WITHDRAW
 extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 
+#define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
+extern void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
+				unsigned long end);
+
 #endif
diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c
index 80e28555a5de..b28731c175b1 100644
--- a/arch/arc/mm/tlb.c
+++ b/arch/arc/mm/tlb.c
@@ -626,6 +626,26 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 	return pgtable;
 }
 
+void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
+			 unsigned long end)
+{
+	unsigned int cpu;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	cpu = smp_processor_id();
+
+	if (likely(asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID)) {
+		unsigned int asid = hw_pid(vma->vm_mm, cpu);
+
+		/* No need to loop here: this will always be for 1 Huge Page */
+		tlb_entry_erase(start | _PAGE_HW_SZ | asid);
+	}
+
+	local_irq_restore(flags);
+}
+
 #endif
 
 /* Read the Cache Build Confuration Registers, Decode them and save into
-- 
1.9.1

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[PATCH v2 12/12] ARCv2: Add a DT which enables THP

[Vineet Gupta]

* Enable THP at bootup
* More than 512M RAM (kernel auto-disabled THP for smaller systems)

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 arch/arc/boot/dts/hs_thp.dts | 59 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 arch/arc/boot/dts/hs_thp.dts

diff --git a/arch/arc/boot/dts/hs_thp.dts b/arch/arc/boot/dts/hs_thp.dts
new file mode 100644
index 000000000000..818a8c968330
--- /dev/null
+++ b/arch/arc/boot/dts/hs_thp.dts
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2015 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+/dts-v1/;
+
+/include/ "skeleton.dtsi"
+
+/ {
+	compatible = "snps,nsim_hs";
+	interrupt-parent = <&core_intc>;
+
+	chosen {
+		bootargs = "earlycon=arc_uart,mmio32,0xc0fc1000,115200n8 console=ttyARC0,115200n8 transparent_hugepage=always";
+	};
+
+	aliases {
+		serial0 = &arcuart0;
+	};
+
+	memory {
+		device_type = "memory";
+		/* reg = <0x00000000 0x28000000>; */
+		reg = <0x00000000 0x40000000>;
+	};
+
+	fpga {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		/* child and parent address space 1:1 mapped */
+		ranges;
+
+		core_intc: core-interrupt-controller {
+			compatible = "snps,archs-intc";
+			interrupt-controller;
+			#interrupt-cells = <1>;
+		};
+
+		arcuart0: serial@c0fc1000 {
+			compatible = "snps,arc-uart";
+			reg = <0xc0fc1000 0x100>;
+			interrupts = <24>;
+			clock-frequency = <80000000>;
+			current-speed = <115200>;
+			status = "okay";
+		};
+
+		arcpct0: pct {
+			compatible = "snps,archs-pct";
+			#interrupt-cells = <1>;
+			interrupts = <20>;
+		};
+	};
+};
-- 
1.9.1

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Re: [PATCH v2 00/12] THP support for ARC

[Vineet Gupta]

On Tuesday 22 September 2015 04:04 PM, Vineet Gupta wrote:
> Hi,
> 
> This series brings THP support to ARC. It also introduces an optional new
> thp hook for arches to possibly optimize the TLB flush in thp regime.
> 
> Please review !
> 
> Changes Since v1 [*]
>    - Rebased against v4.3-rc2
>    - Switched ARC pgtable_t to pte_t * 		(Kiril)
>    - Removed stub implementations for		(Andrew)
> 	pmdp_set_access_flags, pmdp_test_and_clear_young, pmdp_set_wrprotect,
> 	pmdp_collapse_flush, pmd_same
> 
> [*] http://lkml.kernel.org/r/1440666194-21478-1-git-send-email-vgupta@synopsys.com
> 
> Vineet Gupta (12):
>   ARC: mm: switch pgtable_to to pte_t *
>   ARC: mm: pte flags comsetic cleanups, comments
>   ARC: mm: Introduce PTE_SPECIAL
>   Documentation/features/vm: pte_special now supported by ARC
>   ARCv2: mm: THP support
>   ARCv2: mm: THP: boot validation/reporting
>   Documentation/features/vm: THP now supported by ARC
>   mm: move some code around
>   mm,thp: reduce ifdef'ery for THP in generic code
>   mm,thp: introduce flush_pmd_tlb_range
>   ARCv2: mm: THP: Implement flush_pmd_tlb_range() optimization
>   ARCv2: Add a DT which enables THP
> 
>  Documentation/features/vm/THP/arch-support.txt     |  2 +-
>  .../features/vm/pte_special/arch-support.txt       |  2 +-
>  arch/arc/Kconfig                                   |  4 +
>  arch/arc/boot/dts/hs_thp.dts                       | 59 +++++++++++++
>  arch/arc/include/asm/hugepage.h                    | 82 ++++++++++++++++++
>  arch/arc/include/asm/page.h                        |  5 +-
>  arch/arc/include/asm/pgalloc.h                     |  6 +-
>  arch/arc/include/asm/pgtable.h                     | 60 +++++++------
>  arch/arc/mm/tlb.c                                  | 76 ++++++++++++++++-
>  arch/arc/mm/tlbex.S                                | 21 +++--
>  include/asm-generic/pgtable.h                      | 49 ++++-------
>  mm/huge_memory.c                                   |  2 +-
>  mm/pgtable-generic.c                               | 99 ++++++++++------------
>  13 files changed, 345 insertions(+), 122 deletions(-)
>  create mode 100644 arch/arc/boot/dts/hs_thp.dts
>  create mode 100644 arch/arc/include/asm/hugepage.h

Andrew, Kirill, could you please review/ack the generic mm bits atleast so I can
proceed with moving the stuff into linux-next !

Thx,
-Vineet

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Re: [PATCH v2 00/12] THP support for ARC

[Vineet Gupta]

On Thursday 01 October 2015 11:32 AM, Vineet Gupta wrote:
> On Tuesday 22 September 2015 04:04 PM, Vineet Gupta wrote:
>> > Hi,
>> > 
>> > This series brings THP support to ARC. It also introduces an optional new
>> > thp hook for arches to possibly optimize the TLB flush in thp regime.
>> > 
>> > Please review !
>> > 
>> > Changes Since v1 [*]
>> >    - Rebased against v4.3-rc2
>> >    - Switched ARC pgtable_t to pte_t * 		(Kiril)
>> >    - Removed stub implementations for		(Andrew)
>> > 	pmdp_set_access_flags, pmdp_test_and_clear_young, pmdp_set_wrprotect,
>> > 	pmdp_collapse_flush, pmd_same
>> > 
>> > [*] http://lkml.kernel.org/r/1440666194-21478-1-git-send-email-vgupta@synopsys.com
>> > 
>> > Vineet Gupta (12):
>> >   ARC: mm: switch pgtable_to to pte_t *
>> >   ARC: mm: pte flags comsetic cleanups, comments
>> >   ARC: mm: Introduce PTE_SPECIAL
>> >   Documentation/features/vm: pte_special now supported by ARC
>> >   ARCv2: mm: THP support
>> >   ARCv2: mm: THP: boot validation/reporting
>> >   Documentation/features/vm: THP now supported by ARC
>> >   mm: move some code around
>> >   mm,thp: reduce ifdef'ery for THP in generic code
>> >   mm,thp: introduce flush_pmd_tlb_range
>> >   ARCv2: mm: THP: Implement flush_pmd_tlb_range() optimization
>> >   ARCv2: Add a DT which enables THP
>> > 
>> >  Documentation/features/vm/THP/arch-support.txt     |  2 +-
>> >  .../features/vm/pte_special/arch-support.txt       |  2 +-
>> >  arch/arc/Kconfig                                   |  4 +
>> >  arch/arc/boot/dts/hs_thp.dts                       | 59 +++++++++++++
>> >  arch/arc/include/asm/hugepage.h                    | 82 ++++++++++++++++++
>> >  arch/arc/include/asm/page.h                        |  5 +-
>> >  arch/arc/include/asm/pgalloc.h                     |  6 +-
>> >  arch/arc/include/asm/pgtable.h                     | 60 +++++++------
>> >  arch/arc/mm/tlb.c                                  | 76 ++++++++++++++++-
>> >  arch/arc/mm/tlbex.S                                | 21 +++--
>> >  include/asm-generic/pgtable.h                      | 49 ++++-------
>> >  mm/huge_memory.c                                   |  2 +-
>> >  mm/pgtable-generic.c                               | 99 ++++++++++------------
>> >  13 files changed, 345 insertions(+), 122 deletions(-)
>> >  create mode 100644 arch/arc/boot/dts/hs_thp.dts
>> >  create mode 100644 arch/arc/include/asm/hugepage.h
> Andrew, Kirill, could you please review/ack the generic mm bits atleast so I can
> proceed with moving the stuff into linux-next !

Ping 2 ! Can I please get some acks on the generic mm bits. Some of the changes
will likely collide Kirill's THP rework !

Given people rebase off of mmtomm would it be better if generic patches went thru
Andrew and probably included sooner for 4.4 target ?

-Vineet

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Re: [PATCH v2 08/12] mm: move some code around

[Kirill A. Shutemov]

On Tue, Sep 22, 2015 at 04:04:52PM +0530, Vineet Gupta wrote:
> This reduces/simplifies the diff for the next patch which moves THP
> specific code.
> 
> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Okay, so you group pte-related helpers together, right?
It would be nice to mention it in commit message.

Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com

-- 
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Re: [PATCH v2 09/12] mm,thp: reduce ifdef'ery for THP in generic code

[Kirill A. Shutemov]

On Tue, Sep 22, 2015 at 04:04:53PM +0530, Vineet Gupta wrote:
> - pgtable-generic.c: Fold individual #ifdef for each helper into a top
>   level #ifdef. Makes code more readable

Makes sense.

> - Per Andrew's suggestion removed the dummy implementations for !THP
>   in asm-generic/page-table.h to have build time failures vs. runtime.

I'm not sure it's a good idea. This can lead to unnecessary #ifdefs where
otherwise call to helper would be eliminated by compiler as dead code.

What about dummy helpers with BUILD_BUG()?

> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> ---
>  include/asm-generic/pgtable.h | 49 ++++++++++++++++---------------------------
>  mm/pgtable-generic.c          | 24 +++------------------
>  2 files changed, 21 insertions(+), 52 deletions(-)
> 
> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
> index 29c57b2cb344..2112f4147816 100644
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -30,9 +30,12 @@ extern int ptep_set_access_flags(struct vm_area_struct *vma,
>  #endif
>  
>  #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  extern int pmdp_set_access_flags(struct vm_area_struct *vma,
>  				 unsigned long address, pmd_t *pmdp,
>  				 pmd_t entry, int dirty);
> +
> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>  #endif
>  
>  #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
> @@ -64,14 +67,6 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
>  		set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
>  	return r;
>  }
> -#else /* CONFIG_TRANSPARENT_HUGEPAGE */
> -static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
> -					    unsigned long address,
> -					    pmd_t *pmdp)
> -{
> -	BUG();
> -	return 0;
> -}
>  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>  #endif
>  
> @@ -81,8 +76,21 @@ int ptep_clear_flush_young(struct vm_area_struct *vma,
>  #endif
>  
>  #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
> -int pmdp_clear_flush_young(struct vm_area_struct *vma,
> -			   unsigned long address, pmd_t *pmdp);
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
> +				  unsigned long address, pmd_t *pmdp);
> +#else
> +/*
> + * Despite relevant to THP only, this API is called from generic rmap code
> + * under PageTransHuge(), hence needs a dummy implementation for !THP
> + */

Looks like a case I described above. BUILD_BUG_ON() should work fine here.

> +static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
> +					 unsigned long address, pmd_t *pmdp)
> +{
> +	BUG();
> +	return 0;
> +}
> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>  #endif

-- 
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Re: [PATCH v2 08/12] mm: move some code around

[Vineet Gupta]

On Friday 09 October 2015 03:19 PM, Kirill A. Shutemov wrote:
> On Tue, Sep 22, 2015 at 04:04:52PM +0530, Vineet Gupta wrote:
>> This reduces/simplifies the diff for the next patch which moves THP
>> specific code.
>>
>> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> Okay, so you group pte-related helpers together, right?
> It would be nice to mention it in commit message.
>
> Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com

------------->
>From 3817cec40baf8d9bf783203bf42e15dc404d9cdd Mon Sep 17 00:00:00 2001
From: Vineet Gupta <vgupta@synopsys.com>
Date: Thu, 9 Jul 2015 17:19:30 +0530
Subject: [PATCH v3] mm: group pte related helpers together

This reduces/simplifies the diff for the next patch which moves THP
specific code.

No semantical changes !

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 mm/pgtable-generic.c | 50 +++++++++++++++++++++++++-------------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 6b674e00153c..48851894e699 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -57,6 +57,31 @@ int ptep_set_access_flags(struct vm_area_struct *vma,
 }
 #endif
 
+#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
+int ptep_clear_flush_young(struct vm_area_struct *vma,
+               unsigned long address, pte_t *ptep)
+{
+    int young;
+    young = ptep_test_and_clear_young(vma, address, ptep);
+    if (young)
+        flush_tlb_page(vma, address);
+    return young;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
+pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
+               pte_t *ptep)
+{
+    struct mm_struct *mm = (vma)->vm_mm;
+    pte_t pte;
+    pte = ptep_get_and_clear(mm, address, ptep);
+    if (pte_accessible(mm, pte))
+        flush_tlb_page(vma, address);
+    return pte;
+}
+#endif
+
 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 int pmdp_set_access_flags(struct vm_area_struct *vma,
               unsigned long address, pmd_t *pmdp,
@@ -77,18 +102,6 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
 }
 #endif
 
-#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
-int ptep_clear_flush_young(struct vm_area_struct *vma,
-               unsigned long address, pte_t *ptep)
-{
-    int young;
-    young = ptep_test_and_clear_young(vma, address, ptep);
-    if (young)
-        flush_tlb_page(vma, address);
-    return young;
-}
-#endif
-
 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 int pmdp_clear_flush_young(struct vm_area_struct *vma,
                unsigned long address, pmd_t *pmdp)
@@ -106,19 +119,6 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
 }
 #endif
 
-#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
-pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
-               pte_t *ptep)
-{
-    struct mm_struct *mm = (vma)->vm_mm;
-    pte_t pte;
-    pte = ptep_get_and_clear(mm, address, ptep);
-    if (pte_accessible(mm, pte))
-        flush_tlb_page(vma, address);
-    return pte;
-}
-#endif
-
 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
-- 
1.9.1


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Re: [PATCH v2 10/12] mm,thp: introduce flush_pmd_tlb_range

[Kirill A. Shutemov]

On Tue, Sep 22, 2015 at 04:04:54PM +0530, Vineet Gupta wrote:

Commit message: -ENOENT.

Otherwise, looks good:

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

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Re: [PATCH v2 09/12] mm,thp: reduce ifdef'ery for THP in generic code

[Vineet Gupta]

On Friday 09 October 2015 03:24 PM, Kirill A. Shutemov wrote:
> On Tue, Sep 22, 2015 at 04:04:53PM +0530, Vineet Gupta wrote:
>> - pgtable-generic.c: Fold individual #ifdef for each helper into a top
>>   level #ifdef. Makes code more readable
> Makes sense.
>
>> - Per Andrew's suggestion removed the dummy implementations for !THP
>>   in asm-generic/page-table.h to have build time failures vs. runtime.
> I'm not sure it's a good idea. This can lead to unnecessary #ifdefs where
> otherwise call to helper would be eliminated by compiler as dead code.
>
> What about dummy helpers with BUILD_BUG()?

Not really. With this patch, if arch doesn't define __HAVR_ARCH_xyz - we pick the
default implementation. What I changed is if arch defines the __HAVE but doesn't
define the function, then instead of pickign a stub with runtime or buildtime bug
on, we simply fail the build ?

Maybe I can add this to changelog to make it more explicit.

>
>> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
>> ---
>>  include/asm-generic/pgtable.h | 49 ++++++++++++++++---------------------------
>>  mm/pgtable-generic.c          | 24 +++------------------
>>  2 files changed, 21 insertions(+), 52 deletions(-)
>>
>> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
>> index 29c57b2cb344..2112f4147816 100644
>> --- a/include/asm-generic/pgtable.h
>> +++ b/include/asm-generic/pgtable.h
>> @@ -30,9 +30,12 @@ extern int ptep_set_access_flags(struct vm_area_struct *vma,
>>  #endif
>>  
>>  #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
>> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>  extern int pmdp_set_access_flags(struct vm_area_struct *vma,
>>  				 unsigned long address, pmd_t *pmdp,
>>  				 pmd_t entry, int dirty);
>> +
>> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>>  #endif
>>  
>>  #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
>> @@ -64,14 +67,6 @@ static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
>>  		set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd));
>>  	return r;
>>  }
>> -#else /* CONFIG_TRANSPARENT_HUGEPAGE */
>> -static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma,
>> -					    unsigned long address,
>> -					    pmd_t *pmdp)
>> -{
>> -	BUG();
>> -	return 0;
>> -}
>>  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>>  #endif
>>  
>> @@ -81,8 +76,21 @@ int ptep_clear_flush_young(struct vm_area_struct *vma,
>>  #endif
>>  
>>  #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
>> -int pmdp_clear_flush_young(struct vm_area_struct *vma,
>> -			   unsigned long address, pmd_t *pmdp);
>> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>> +extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
>> +				  unsigned long address, pmd_t *pmdp);
>> +#else
>> +/*
>> + * Despite relevant to THP only, this API is called from generic rmap code
>> + * under PageTransHuge(), hence needs a dummy implementation for !THP
>> + */
> Looks like a case I described above. BUILD_BUG_ON() should work fine here.

Indeed BUILD_BUG_ON is better here.

>
>> +static inline int pmdp_clear_flush_young(struct vm_area_struct *vma,
>> +					 unsigned long address, pmd_t *pmdp)
>> +{
>> +	BUG();
>> +	return 0;
>> +}
>> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>>  #endif


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Re: [PATCH v2 00/12] THP support for ARC

[Kirill A. Shutemov]

On Fri, Oct 09, 2015 at 03:03:26PM +0530, Vineet Gupta wrote:
> On Thursday 01 October 2015 11:32 AM, Vineet Gupta wrote:
> > On Tuesday 22 September 2015 04:04 PM, Vineet Gupta wrote:
> >> > Hi,
> >> > 
> >> > This series brings THP support to ARC. It also introduces an optional new
> >> > thp hook for arches to possibly optimize the TLB flush in thp regime.
> >> > 
> >> > Please review !
> >> > 
> >> > Changes Since v1 [*]
> >> >    - Rebased against v4.3-rc2
> >> >    - Switched ARC pgtable_t to pte_t * 		(Kiril)
> >> >    - Removed stub implementations for		(Andrew)
> >> > 	pmdp_set_access_flags, pmdp_test_and_clear_young, pmdp_set_wrprotect,
> >> > 	pmdp_collapse_flush, pmd_same
> >> > 
> >> > [*] http://lkml.kernel.org/r/1440666194-21478-1-git-send-email-vgupta@synopsys.com
> >> > 
> >> > Vineet Gupta (12):
> >> >   ARC: mm: switch pgtable_to to pte_t *
> >> >   ARC: mm: pte flags comsetic cleanups, comments
> >> >   ARC: mm: Introduce PTE_SPECIAL
> >> >   Documentation/features/vm: pte_special now supported by ARC
> >> >   ARCv2: mm: THP support
> >> >   ARCv2: mm: THP: boot validation/reporting
> >> >   Documentation/features/vm: THP now supported by ARC
> >> >   mm: move some code around
> >> >   mm,thp: reduce ifdef'ery for THP in generic code
> >> >   mm,thp: introduce flush_pmd_tlb_range
> >> >   ARCv2: mm: THP: Implement flush_pmd_tlb_range() optimization
> >> >   ARCv2: Add a DT which enables THP
> >> > 
> >> >  Documentation/features/vm/THP/arch-support.txt     |  2 +-
> >> >  .../features/vm/pte_special/arch-support.txt       |  2 +-
> >> >  arch/arc/Kconfig                                   |  4 +
> >> >  arch/arc/boot/dts/hs_thp.dts                       | 59 +++++++++++++
> >> >  arch/arc/include/asm/hugepage.h                    | 82 ++++++++++++++++++
> >> >  arch/arc/include/asm/page.h                        |  5 +-
> >> >  arch/arc/include/asm/pgalloc.h                     |  6 +-
> >> >  arch/arc/include/asm/pgtable.h                     | 60 +++++++------
> >> >  arch/arc/mm/tlb.c                                  | 76 ++++++++++++++++-
> >> >  arch/arc/mm/tlbex.S                                | 21 +++--
> >> >  include/asm-generic/pgtable.h                      | 49 ++++-------
> >> >  mm/huge_memory.c                                   |  2 +-
> >> >  mm/pgtable-generic.c                               | 99 ++++++++++------------
> >> >  13 files changed, 345 insertions(+), 122 deletions(-)
> >> >  create mode 100644 arch/arc/boot/dts/hs_thp.dts
> >> >  create mode 100644 arch/arc/include/asm/hugepage.h
> > Andrew, Kirill, could you please review/ack the generic mm bits atleast so I can
> > proceed with moving the stuff into linux-next !
> 
> Ping 2 !

Sorry.

> Can I please get some acks on the generic mm bits. Some of the changes
> will likely collide Kirill's THP rework !

Could you check if it acctually collides?

> Given people rebase off of mmtomm would it be better if generic patches went thru
> Andrew and probably included sooner for 4.4 target ?
> 
> -Vineet
> 
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Re: [PATCH v2 09/12] mm,thp: reduce ifdef'ery for THP in generic code

[Vineet Gupta]

On Friday 09 October 2015 03:23 PM, Kirill A. Shutemov wrote:
> On Tue, Sep 22, 2015 at 04:04:53PM +0530, Vineet Gupta wrote:
>> > - pgtable-generic.c: Fold individual #ifdef for each helper into a top
>> >   level #ifdef. Makes code more readable
> Makes sense.
> 
>> > - Per Andrew's suggestion removed the dummy implementations for !THP
>> >   in asm-generic/page-table.h to have build time failures vs. runtime.
> I'm not sure it's a good idea. This can lead to unnecessary #ifdefs where
> otherwise call to helper would be eliminated by compiler as dead code.
> 
> What about dummy helpers with BUILD_BUG()?
> 

You are right after all. It is not so much related to __HAVE_ARCH_PMDP_xyz, but
the fact that generic code can call them under PageTransHuge(). So better to
provide stubs with BUILD_BUG

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Re: [PATCH v2 10/12] mm,thp: introduce flush_pmd_tlb_range

[Vineet Gupta]

On Friday 09 October 2015 03:38 PM, Kirill A. Shutemov wrote:
> On Tue, Sep 22, 2015 at 04:04:54PM +0530, Vineet Gupta wrote:
> 
> Commit message: -ENOENT.
> 
> Otherwise, looks good:
> 
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

With updated change log and some reworking in the source code comment !

---------------->

Re: [PATCH v2 00/12] THP support for ARC

[Vineet Gupta]

On Friday 09 October 2015 03:40 PM, Kirill A. Shutemov wrote:
> On Fri, Oct 09, 2015 at 03:03:26PM +0530, Vineet Gupta wrote:
>> On Thursday 01 October 2015 11:32 AM, Vineet Gupta wrote:
>>> On Tuesday 22 September 2015 04:04 PM, Vineet Gupta wrote:
>>>>> Hi,
>>>>>
>>>>> This series brings THP support to ARC. It also introduces an optional new
>>>>> thp hook for arches to possibly optimize the TLB flush in thp regime.
>>>>>
>>>>> Please review !
>>>>>
>>>>> Changes Since v1 [*]
>>>>>    - Rebased against v4.3-rc2
>>>>>    - Switched ARC pgtable_t to pte_t * 		(Kiril)
>>>>>    - Removed stub implementations for		(Andrew)
>>>>> 	pmdp_set_access_flags, pmdp_test_and_clear_young, pmdp_set_wrprotect,
>>>>> 	pmdp_collapse_flush, pmd_same
>>>>>
>>>>> [*] http://lkml.kernel.org/r/1440666194-21478-1-git-send-email-vgupta@synopsys.com
>>>>>
>>>>> Vineet Gupta (12):
>>>>>   ARC: mm: switch pgtable_to to pte_t *
>>>>>   ARC: mm: pte flags comsetic cleanups, comments
>>>>>   ARC: mm: Introduce PTE_SPECIAL
>>>>>   Documentation/features/vm: pte_special now supported by ARC
>>>>>   ARCv2: mm: THP support
>>>>>   ARCv2: mm: THP: boot validation/reporting
>>>>>   Documentation/features/vm: THP now supported by ARC
>>>>>   mm: move some code around
>>>>>   mm,thp: reduce ifdef'ery for THP in generic code
>>>>>   mm,thp: introduce flush_pmd_tlb_range
>>>>>   ARCv2: mm: THP: Implement flush_pmd_tlb_range() optimization
>>>>>   ARCv2: Add a DT which enables THP
>>>>>
>>>>>  Documentation/features/vm/THP/arch-support.txt     |  2 +-
>>>>>  .../features/vm/pte_special/arch-support.txt       |  2 +-
>>>>>  arch/arc/Kconfig                                   |  4 +
>>>>>  arch/arc/boot/dts/hs_thp.dts                       | 59 +++++++++++++
>>>>>  arch/arc/include/asm/hugepage.h                    | 82 ++++++++++++++++++
>>>>>  arch/arc/include/asm/page.h                        |  5 +-
>>>>>  arch/arc/include/asm/pgalloc.h                     |  6 +-
>>>>>  arch/arc/include/asm/pgtable.h                     | 60 +++++++------
>>>>>  arch/arc/mm/tlb.c                                  | 76 ++++++++++++++++-
>>>>>  arch/arc/mm/tlbex.S                                | 21 +++--
>>>>>  include/asm-generic/pgtable.h                      | 49 ++++-------
>>>>>  mm/huge_memory.c                                   |  2 +-
>>>>>  mm/pgtable-generic.c                               | 99 ++++++++++------------
>>>>>  13 files changed, 345 insertions(+), 122 deletions(-)
>>>>>  create mode 100644 arch/arc/boot/dts/hs_thp.dts
>>>>>  create mode 100644 arch/arc/include/asm/hugepage.h
>>> Andrew, Kirill, could you please review/ack the generic mm bits atleast so I can
>>> proceed with moving the stuff into linux-next !
>>
>> Ping 2 !
> 
> Sorry.
> 
>> Can I please get some acks on the generic mm bits. Some of the changes
>> will likely collide Kirill's THP rework !
> 
> Could you check if it acctually collides?

I rebased my changes on top of your v12 branch. As expected I get two merge
conflicts as my patches update code which u have removed. But looks straight
forward to resolve. Meaning we can carry respective patches and give Linus a heads
up abt the merge conflict.

There's also a fixup needed for ARC to remove the pmdp splitting assuming ARC THP
makes it into mainline first.

-Vineet

> 
>> Given people rebase off of mmtomm would it be better if generic patches went thru
>> Andrew and probably included sooner for 4.4 target ?
>>
>> -Vineet
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@kvack.org.  For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
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Re: [PATCH v2 00/12] THP support for ARC

[Kirill A. Shutemov]

On Fri, Oct 09, 2015 at 04:59:43PM +0530, Vineet Gupta wrote:
> On Friday 09 October 2015 03:40 PM, Kirill A. Shutemov wrote:
> > On Fri, Oct 09, 2015 at 03:03:26PM +0530, Vineet Gupta wrote:
> >> On Thursday 01 October 2015 11:32 AM, Vineet Gupta wrote:
> >>> On Tuesday 22 September 2015 04:04 PM, Vineet Gupta wrote:
> >>>>> Hi,
> >>>>>
> >>>>> This series brings THP support to ARC. It also introduces an optional new
> >>>>> thp hook for arches to possibly optimize the TLB flush in thp regime.
> >>>>>
> >>>>> Please review !
> >>>>>
> >>>>> Changes Since v1 [*]
> >>>>>    - Rebased against v4.3-rc2
> >>>>>    - Switched ARC pgtable_t to pte_t * 		(Kiril)
> >>>>>    - Removed stub implementations for		(Andrew)
> >>>>> 	pmdp_set_access_flags, pmdp_test_and_clear_young, pmdp_set_wrprotect,
> >>>>> 	pmdp_collapse_flush, pmd_same
> >>>>>
> >>>>> [*] http://lkml.kernel.org/r/1440666194-21478-1-git-send-email-vgupta@synopsys.com
> >>>>>
> >>>>> Vineet Gupta (12):
> >>>>>   ARC: mm: switch pgtable_to to pte_t *
> >>>>>   ARC: mm: pte flags comsetic cleanups, comments
> >>>>>   ARC: mm: Introduce PTE_SPECIAL
> >>>>>   Documentation/features/vm: pte_special now supported by ARC
> >>>>>   ARCv2: mm: THP support
> >>>>>   ARCv2: mm: THP: boot validation/reporting
> >>>>>   Documentation/features/vm: THP now supported by ARC
> >>>>>   mm: move some code around
> >>>>>   mm,thp: reduce ifdef'ery for THP in generic code
> >>>>>   mm,thp: introduce flush_pmd_tlb_range
> >>>>>   ARCv2: mm: THP: Implement flush_pmd_tlb_range() optimization
> >>>>>   ARCv2: Add a DT which enables THP
> >>>>>
> >>>>>  Documentation/features/vm/THP/arch-support.txt     |  2 +-
> >>>>>  .../features/vm/pte_special/arch-support.txt       |  2 +-
> >>>>>  arch/arc/Kconfig                                   |  4 +
> >>>>>  arch/arc/boot/dts/hs_thp.dts                       | 59 +++++++++++++
> >>>>>  arch/arc/include/asm/hugepage.h                    | 82 ++++++++++++++++++
> >>>>>  arch/arc/include/asm/page.h                        |  5 +-
> >>>>>  arch/arc/include/asm/pgalloc.h                     |  6 +-
> >>>>>  arch/arc/include/asm/pgtable.h                     | 60 +++++++------
> >>>>>  arch/arc/mm/tlb.c                                  | 76 ++++++++++++++++-
> >>>>>  arch/arc/mm/tlbex.S                                | 21 +++--
> >>>>>  include/asm-generic/pgtable.h                      | 49 ++++-------
> >>>>>  mm/huge_memory.c                                   |  2 +-
> >>>>>  mm/pgtable-generic.c                               | 99 ++++++++++------------
> >>>>>  13 files changed, 345 insertions(+), 122 deletions(-)
> >>>>>  create mode 100644 arch/arc/boot/dts/hs_thp.dts
> >>>>>  create mode 100644 arch/arc/include/asm/hugepage.h
> >>> Andrew, Kirill, could you please review/ack the generic mm bits atleast so I can
> >>> proceed with moving the stuff into linux-next !
> >>
> >> Ping 2 !
> > 
> > Sorry.
> > 
> >> Can I please get some acks on the generic mm bits. Some of the changes
> >> will likely collide Kirill's THP rework !
> > 
> > Could you check if it acctually collides?
> 
> I rebased my changes on top of your v12 branch. As expected I get two merge
> conflicts as my patches update code which u have removed. But looks straight
> forward to resolve. Meaning we can carry respective patches and give Linus a heads
> up abt the merge conflict.
> 
> There's also a fixup needed for ARC to remove the pmdp splitting assuming ARC THP
> makes it into mainline first.

Okay. Let's see what hits upstream first.

Side question: I was surprised by your patchset. I didn't think about ARC
as an architecture which would benefit from THP. How big ARC systems
nowadays? How big benefit did you measured there from THP? 

-- 
 Kirill A. Shutemov

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Re: [PATCH v2 00/12] THP support for ARC

[Vineet Gupta]

On Friday 09 October 2015 05:13 PM, Kirill A. Shutemov wrote:
> Side question: I was surprised by your patchset. I didn't think about ARC
> as an architecture which would benefit from THP. How big ARC systems
> nowadays? How big benefit did you measured there from THP? 

Hardware support for THP on ARC is relatively recent - as part of newly announced
HS38x cores. So we don't have silicon yet to measure the performance benefits. I'm
currently testing this on our nsim simulator but we are slated to get silicon with
this pretty soon.

If you were surprised by this you will likely be more with my highmem / PAE40
support patches which I will send out early next week ;-)

Customers these days want more future safety, if nothing else and these features
were added per more of them wanting these in their designs.

Thx for taking time to go thru this stuff !
-Vineet

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