[PATCH] mips/mm: Add page soft dirty tracking

From: Guoyun Sun
Date: Tue Apr 21 2020 - 05:16:10 EST


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.

Signed-off-by: Guoyun Sun <sunguoyun@xxxxxxxxxxx>
---
arch/mips/Kconfig | 1 +
arch/mips/include/asm/pgtable-bits.h | 8 ++++--
arch/mips/include/asm/pgtable.h | 48 ++++++++++++++++++++++++++++++++++--
3 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 690718b..642fb47 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -491,6 +491,7 @@ config MACH_LOONGSON64
select COMMON_CLK
select USE_OF
select BUILTIN_DTB
+ select HAVE_ARCH_SOFT_DIRTY
help
This enables the support of Loongson-2/3 family of machines.

diff --git a/arch/mips/include/asm/pgtable-bits.h b/arch/mips/include/asm/pgtable-bits.h
index 4da79b8..d43fb6f 100644
--- a/arch/mips/include/asm/pgtable-bits.h
+++ b/arch/mips/include/asm/pgtable-bits.h
@@ -55,6 +55,7 @@ enum pgtable_bits {
#if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
_PAGE_SPECIAL_SHIFT,
#endif
+ _PAGE_SOFT_DIRTY_SHIFT,
};

/*
@@ -84,6 +85,7 @@ enum pgtable_bits {
#if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
_PAGE_SPECIAL_SHIFT,
#endif
+ _PAGE_SOFT_DIRTY_SHIFT,
};

#elif defined(CONFIG_CPU_R3K_TLB)
@@ -99,6 +101,7 @@ enum pgtable_bits {
#if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
_PAGE_SPECIAL_SHIFT,
#endif
+ _PAGE_SOFT_DIRTY_SHIFT,

/* Used by TLB hardware (placed in EntryLo) */
_PAGE_GLOBAL_SHIFT = 8,
@@ -125,7 +128,7 @@ enum pgtable_bits {
#if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
_PAGE_SPECIAL_SHIFT,
#endif
-
+ _PAGE_SOFT_DIRTY_SHIFT,
/* Used by TLB hardware (placed in EntryLo*) */
#if defined(CONFIG_CPU_HAS_RIXI)
_PAGE_NO_EXEC_SHIFT,
@@ -152,6 +155,7 @@ enum pgtable_bits {
#else
# define _PAGE_SPECIAL 0
#endif
+#define _PAGE_SOFT_DIRTY (1 << _PAGE_SOFT_DIRTY_SHIFT)

/* Used by TLB hardware (placed in EntryLo*) */
#if defined(CONFIG_XPA)
@@ -269,6 +273,6 @@ static inline uint64_t pte_to_entrylo(unsigned long pte_val)
#define __WRITEABLE (_PAGE_SILENT_WRITE | _PAGE_WRITE | _PAGE_MODIFIED)

#define _PAGE_CHG_MASK (_PAGE_ACCESSED | _PAGE_MODIFIED | \
- _PFN_MASK | _CACHE_MASK)
+ _PAGE_SOFT_DIRTY | _PFN_MASK | _CACHE_MASK)

#endif /* _ASM_PGTABLE_BITS_H */
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index f1801e7..64b07ff 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -400,7 +400,7 @@ static inline pte_t pte_mkwrite(pte_t pte)

static inline pte_t pte_mkdirty(pte_t pte)
{
- pte_val(pte) |= _PAGE_MODIFIED;
+ pte_val(pte) |= _PAGE_MODIFIED | _PAGE_SOFT_DIRTY;
if (pte_val(pte) & _PAGE_WRITE)
pte_val(pte) |= _PAGE_SILENT_WRITE;
return pte;
@@ -423,6 +423,30 @@ static inline pte_t pte_mkhuge(pte_t pte)
return pte;
}
#endif /* CONFIG_MIPS_HUGE_TLB_SUPPORT */
+
+#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
+static inline bool pte_soft_dirty(pte_t pte)
+{
+ return pte_val(pte) & _PAGE_SOFT_DIRTY;
+}
+#define pte_swp_soft_dirty pte_soft_dirty
+
+static inline pte_t pte_mksoft_dirty(pte_t pte)
+{
+ pte_val(pte) |= _PAGE_SOFT_DIRTY;
+ return pte;
+}
+#define pte_swp_mksoft_dirty pte_mksoft_dirty
+
+static inline pte_t pte_clear_soft_dirty(pte_t pte)
+{
+ pte_val(pte) &= ~(_PAGE_SOFT_DIRTY);
+ return pte;
+}
+#define pte_swp_clear_soft_dirty pte_clear_soft_dirty
+
+#endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */
+
#endif

/*
@@ -579,7 +603,7 @@ static inline pmd_t pmd_mkclean(pmd_t pmd)

static inline pmd_t pmd_mkdirty(pmd_t pmd)
{
- pmd_val(pmd) |= _PAGE_MODIFIED;
+ pmd_val(pmd) |= _PAGE_MODIFIED | _PAGE_SOFT_DIRTY;
if (pmd_val(pmd) & _PAGE_WRITE)
pmd_val(pmd) |= _PAGE_SILENT_WRITE;

@@ -608,6 +632,26 @@ static inline pmd_t pmd_mkyoung(pmd_t pmd)
return pmd;
}

+#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
+static inline int pmd_soft_dirty(pmd_t pmd)
+{
+ return !!(pmd_val(pmd) & _PAGE_SOFT_DIRTY);
+}
+
+static inline pmd_t pmd_mksoft_dirty(pmd_t pmd)
+{
+ pmd_val(pmd) |= _PAGE_SOFT_DIRTY;
+ return pmd;
+}
+
+static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd)
+{
+ pmd_val(pmd) &= ~(_PAGE_SOFT_DIRTY);
+ return pmd;
+}
+
+#endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */
+
/* Extern to avoid header file madness */
extern pmd_t mk_pmd(struct page *page, pgprot_t prot);

--
2.1.0