[PATCH v5] powerpc/mm: Add page soft dirty tracking
Laurent Dufour
ldufour at linux.vnet.ibm.com
Thu Dec 3 21:29:19 AEDT 2015
User space checkpoint and restart tool (CRIU) needs the page's change
to be soft tracked. This allows to do a pre checkpoint and then dump
only touched pages.
This is done by using a newly assigned PTE bit (_PAGE_SOFT_DIRTY) when
the page is backed in memory, and a new _PAGE_SWP_SOFT_DIRTY bit when
the page is swapped out.
To introduce a new PTE _PAGE_SOFT_DIRTY bit value common to hash 4k
and hash 64k pte, the bits already defined in hash-*4k.h should be
shifted left by one.
The _PAGE_SWP_SOFT_DIRTY bit is dynamically put after the swap type in
the swap pte. A check is added to ensure that the bit is not
overwritten by _PAGE_HPTEFLAGS.
Signed-off-by: Laurent Dufour <ldufour at linux.vnet.ibm.com>
CC: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
---
This patch should to be applied on top of the Aneesh's series titled
"[PATCH V6 00/35] powerpc/mm: Update page table format for book3s 64"
v5:
- Use boolean type as reported by Denis Kirjanov
v4:
- updated to match Aneesh's v6 series.
V3:
- updated to match Aneesh's changes in the pte handling
- updated to match commit a7b761749317 ("mm: add architecture
primitives for software dirty bit clearing")
V2:
- Fix allnoconfig build
arch/powerpc/Kconfig | 2 ++
arch/powerpc/include/asm/book3s/64/hash-4k.h | 2 +-
arch/powerpc/include/asm/book3s/64/hash-64k.h | 4 ++--
arch/powerpc/include/asm/book3s/64/hash.h | 30 ++++++++++++++++++++++-----
arch/powerpc/include/asm/book3s/64/pgtable.h | 26 +++++++++++++++++++++++
5 files changed, 56 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index db49e0d796b1..6e03f85b11cd 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -559,6 +559,7 @@ choice
config PPC_4K_PAGES
bool "4k page size"
+ select HAVE_ARCH_SOFT_DIRTY if CHECKPOINT_RESTORE && PPC_BOOK3S
config PPC_16K_PAGES
bool "16k page size"
@@ -567,6 +568,7 @@ config PPC_16K_PAGES
config PPC_64K_PAGES
bool "64k page size"
depends on !PPC_FSL_BOOK3E && (44x || PPC_STD_MMU_64 || PPC_BOOK3E_64)
+ select HAVE_ARCH_SOFT_DIRTY if CHECKPOINT_RESTORE && PPC_BOOK3S
config PPC_256K_PAGES
bool "256k page size"
diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
index e59832c94609..ea0414d6659e 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
@@ -52,7 +52,7 @@
_PAGE_F_SECOND | _PAGE_F_GIX)
/* shift to put page number into pte */
-#define PTE_RPN_SHIFT (17)
+#define PTE_RPN_SHIFT (18)
#define _PAGE_4K_PFN 0
#ifndef __ASSEMBLY__
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index 9f9942998587..9e55e3b1fef0 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -25,8 +25,8 @@
#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
#define PGDIR_MASK (~(PGDIR_SIZE-1))
-#define _PAGE_COMBO 0x00020000 /* this is a combo 4k page */
-#define _PAGE_4K_PFN 0x00040000 /* PFN is for a single 4k page */
+#define _PAGE_COMBO 0x00040000 /* this is a combo 4k page */
+#define _PAGE_4K_PFN 0x00080000 /* PFN is for a single 4k page */
/*
* Used to track subpage group valid if _PAGE_COMBO is set
* This overloads _PAGE_F_GIX and _PAGE_F_SECOND
diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index 8b929e531758..9e861b4378bd 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -33,6 +33,7 @@
#define _PAGE_F_GIX_SHIFT 12
#define _PAGE_F_SECOND 0x08000 /* Whether to use secondary hash or not */
#define _PAGE_SPECIAL 0x10000 /* software: special page */
+#define _PAGE_SOFT_DIRTY 0x20000 /* software: software dirty tracking */
/*
* THP pages can't be special. So use the _PAGE_SPECIAL
@@ -50,7 +51,7 @@
*/
#define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | \
_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_SPLITTING | \
- _PAGE_THP_HUGE | _PAGE_PTE)
+ _PAGE_THP_HUGE | _PAGE_PTE | _PAGE_SOFT_DIRTY)
#ifdef CONFIG_PPC_64K_PAGES
#include <asm/book3s/64/hash-64k.h>
@@ -136,14 +137,16 @@
* pgprot changes
*/
#define _PAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
- _PAGE_ACCESSED | _PAGE_SPECIAL | _PAGE_PTE)
+ _PAGE_ACCESSED | _PAGE_SPECIAL | _PAGE_PTE | \
+ _PAGE_SOFT_DIRTY)
/*
* Mask of bits returned by pte_pgprot()
*/
#define PAGE_PROT_BITS (_PAGE_GUARDED | _PAGE_COHERENT | _PAGE_NO_CACHE | \
_PAGE_WRITETHRU | _PAGE_4K_PFN | \
_PAGE_USER | _PAGE_ACCESSED | \
- _PAGE_RW | _PAGE_DIRTY | _PAGE_EXEC)
+ _PAGE_RW | _PAGE_DIRTY | _PAGE_EXEC | \
+ _PAGE_SOFT_DIRTY)
/*
* We define 2 sets of base prot bits, one for basic pages (ie,
* cacheable kernel and user pages) and one for non cacheable
@@ -339,7 +342,8 @@ static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry)
{
unsigned long bits = pte_val(entry) &
- (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);
+ (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC |
+ _PAGE_SOFT_DIRTY);
unsigned long old, tmp;
@@ -366,6 +370,22 @@ static inline int pte_special(pte_t pte) { return !!(pte_val(pte) & _PAGE_SPECIA
static inline int pte_none(pte_t pte) { return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
static inline pgprot_t pte_pgprot(pte_t pte) { return __pgprot(pte_val(pte) & PAGE_PROT_BITS); }
+#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
+static inline bool pte_soft_dirty(pte_t pte)
+{
+ return !!(pte_val(pte) & _PAGE_SOFT_DIRTY);
+}
+static inline pte_t pte_mksoft_dirty(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_SOFT_DIRTY);
+}
+
+static inline pte_t pte_clear_soft_dirty(pte_t pte)
+{
+ return __pte(pte_val(pte) & ~_PAGE_SOFT_DIRTY);
+}
+#endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */
+
#ifdef CONFIG_NUMA_BALANCING
/*
* These work without NUMA balancing but the kernel does not care. See the
@@ -424,7 +444,7 @@ static inline pte_t pte_mkwrite(pte_t pte)
static inline pte_t pte_mkdirty(pte_t pte)
{
- return __pte(pte_val(pte) | _PAGE_DIRTY);
+ return __pte(pte_val(pte) | _PAGE_DIRTY | _PAGE_SOFT_DIRTY);
}
static inline pte_t pte_mkyoung(pte_t pte)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index a2d4e0e37067..03c1a5a21c0c 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -146,6 +146,7 @@ static inline void pgd_set(pgd_t *pgdp, unsigned long val)
* We filter HPTEFLAGS on set_pte. \
*/ \
BUILD_BUG_ON(_PAGE_HPTEFLAGS & (0x1f << _PAGE_BIT_SWAP_TYPE)); \
+ BUILD_BUG_ON(_PAGE_HPTEFLAGS & _PAGE_SWP_SOFT_DIRTY); \
} while (0)
/*
* on pte we don't need handle RADIX_TREE_EXCEPTIONAL_SHIFT;
@@ -161,6 +162,24 @@ static inline void pgd_set(pgd_t *pgdp, unsigned long val)
#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val((pte)) })
#define __swp_entry_to_pte(x) __pte((x).val)
+#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
+#define _PAGE_SWP_SOFT_DIRTY (1UL << (SWP_TYPE_BITS + _PAGE_BIT_SWAP_TYPE))
+static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_SWP_SOFT_DIRTY);
+}
+static inline bool pte_swp_soft_dirty(pte_t pte)
+{
+ return !!(pte_val(pte) & _PAGE_SWP_SOFT_DIRTY);
+}
+static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
+{
+ return __pte(pte_val(pte) & ~_PAGE_SWP_SOFT_DIRTY);
+}
+#else
+#define _PAGE_SWP_SOFT_DIRTY 0
+#endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */
+
void pgtable_cache_add(unsigned shift, void (*ctor)(void *));
void pgtable_cache_init(void);
@@ -201,6 +220,13 @@ static inline pte_t *pmdp_ptep(pmd_t *pmd)
#define pmd_mkdirty(pmd) pte_pmd(pte_mkdirty(pmd_pte(pmd)))
#define pmd_mkyoung(pmd) pte_pmd(pte_mkyoung(pmd_pte(pmd)))
#define pmd_mkwrite(pmd) pte_pmd(pte_mkwrite(pmd_pte(pmd)))
+
+#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
+#define pmd_soft_dirty(pmd) pte_soft_dirty(pmd_pte(pmd))
+#define pmd_mksoft_dirty(pmd) pte_pmd(pte_mksoft_dirty(pmd_pte(pmd)))
+#define pmd_clear_soft_dirty(pmd) pte_pmd(pte_clear_soft_dirty(pmd_pte(pmd)))
+#endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */
+
#ifdef CONFIG_NUMA_BALANCING
static inline int pmd_protnone(pmd_t pmd)
{
--
1.9.1
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