Soft dirty bit is designed to keep tracked over page migration. This patch
makes it work in the same manner for thp migration too.
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
ChangeLog v1 -> v2:
- separate diff moving _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 6
- clear_soft_dirty_pmd can handle migration entry
---
arch/x86/include/asm/pgtable.h | 17 +++++++++++++++++
fs/proc/task_mmu.c | 17 +++++++++++------
include/asm-generic/pgtable.h | 34 +++++++++++++++++++++++++++++++++-
include/linux/swapops.h | 2 ++
mm/huge_memory.c | 25 +++++++++++++++++++++++--
5 files changed, 86 insertions(+), 9 deletions(-)
diff --git v4.9-rc2-mmotm-2016-10-27-18-27/arch/x86/include/asm/pgtable.h v4.9-rc2-mmotm-2016-10-27-18-27_patched/arch/x86/include/asm/pgtable.h
index 437feb4..ceec210 100644
--- v4.9-rc2-mmotm-2016-10-27-18-27/arch/x86/include/asm/pgtable.h
+++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/arch/x86/include/asm/pgtable.h
@@ -948,6 +948,23 @@ static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
{
return pte_clear_flags(pte, _PAGE_SWP_SOFT_DIRTY);
}
+
+#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
+static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
+{
+ return pmd_set_flags(pmd, _PAGE_SWP_SOFT_DIRTY);
+}
+
+static inline int pmd_swp_soft_dirty(pmd_t pmd)
+{
+ return pmd_flags(pmd) & _PAGE_SWP_SOFT_DIRTY;
+}
+
+static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
+{
+ return pmd_clear_flags(pmd, _PAGE_SWP_SOFT_DIRTY);
+}
+#endif
#endif
#define PKRU_AD_BIT 0x1
diff --git v4.9-rc2-mmotm-2016-10-27-18-27/fs/proc/task_mmu.c v4.9-rc2-mmotm-2016-10-27-18-27_patched/fs/proc/task_mmu.c
index c1f9cf4..85745b9 100644
--- v4.9-rc2-mmotm-2016-10-27-18-27/fs/proc/task_mmu.c
+++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/fs/proc/task_mmu.c
@@ -900,12 +900,17 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp)
{
- pmd_t pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
-
- pmd = pmd_wrprotect(pmd);
- pmd = pmd_clear_soft_dirty(pmd);
-
- set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+ pmd_t pmd = *pmdp;
+
+ if (pmd_present(pmd)) {
+ pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
+ pmd = pmd_wrprotect(pmd);
+ pmd = pmd_clear_soft_dirty(pmd);
+ set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+ } else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
+ pmd = pmd_swp_clear_soft_dirty(pmd);
+ set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+ }
}
#else
static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
diff --git v4.9-rc2-mmotm-2016-10-27-18-27/include/asm-generic/pgtable.h v4.9-rc2-mmotm-2016-10-27-18-27_patched/include/asm-generic/pgtable.h
index c4f8fd2..f50e8b4 100644
--- v4.9-rc2-mmotm-2016-10-27-18-27/include/asm-generic/pgtable.h
+++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/include/asm-generic/pgtable.h
@@ -489,7 +489,24 @@ static inline void ptep_modify_prot_commit(struct mm_struct *mm,
#define arch_start_context_switch(prev) do {} while (0)
#endif
-#ifndef CONFIG_HAVE_ARCH_SOFT_DIRTY
+#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
+#ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION
+static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+
+static inline int pmd_swp_soft_dirty(pmd_t pmd)
+{
+ return 0;
+}
+
+static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+#endif
+#else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */
static inline int pte_soft_dirty(pte_t pte)
{
return 0;
@@ -534,6 +551,21 @@ static inline pte_t pte_swp_clear_soft_dirty(pte_t pte)
{
return pte;
}
+
+static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
+
+static inline int pmd_swp_soft_dirty(pmd_t pmd)
+{
+ return 0;
+}
+
+static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd)
+{
+ return pmd;
+}
#endif
#ifndef __HAVE_PFNMAP_TRACKING
diff --git v4.9-rc2-mmotm-2016-10-27-18-27/include/linux/swapops.h v4.9-rc2-mmotm-2016-10-27-18-27_patched/include/linux/swapops.h
index b6b22a2..db8a858 100644
--- v4.9-rc2-mmotm-2016-10-27-18-27/include/linux/swapops.h
+++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/include/linux/swapops.h
@@ -176,6 +176,8 @@ static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
{
swp_entry_t arch_entry;
+ if (pmd_swp_soft_dirty(pmd))
+ pmd = pmd_swp_clear_soft_dirty(pmd);
arch_entry = __pmd_to_swp_entry(pmd);
return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
}
diff --git v4.9-rc2-mmotm-2016-10-27-18-27/mm/huge_memory.c v4.9-rc2-mmotm-2016-10-27-18-27_patched/mm/huge_memory.c
index 4e9090c..bd9c23e 100644
--- v4.9-rc2-mmotm-2016-10-27-18-27/mm/huge_memory.c
+++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/mm/huge_memory.c
@@ -832,6 +832,8 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
if (is_write_migration_entry(entry)) {
make_migration_entry_read(&entry);
pmd = swp_entry_to_pmd(entry);
+ if (pmd_swp_soft_dirty(pmd))
+ pmd = pmd_swp_mksoft_dirty(pmd);
set_pmd_at(src_mm, addr, src_pmd, pmd);
}
set_pmd_at(dst_mm, addr, dst_pmd, pmd);
@@ -1470,6 +1472,17 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
return 1;
}
+static pmd_t move_soft_dirty_pmd(pmd_t pmd)
+{
+#ifdef CONFIG_MEM_SOFT_DIRTY
+ if (unlikely(is_pmd_migration_entry(pmd)))
+ pmd = pmd_mksoft_dirty(pmd);
+ else if (pmd_present(pmd))
+ pmd = pmd_swp_mksoft_dirty(pmd);
+#endif
+ return pmd;
+}
+
bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
unsigned long new_addr, unsigned long old_end,
pmd_t *old_pmd, pmd_t *new_pmd)
@@ -1510,7 +1523,8 @@ bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
pgtable = pgtable_trans_huge_withdraw(mm, old_pmd);
pgtable_trans_huge_deposit(mm, new_pmd, pgtable);
}
- set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd));
+ pmd = move_soft_dirty_pmd(pmd);
+ set_pmd_at(mm, new_addr, new_pmd, pmd);
if (new_ptl != old_ptl)
spin_unlock(new_ptl);
spin_unlock(old_ptl);
@@ -1556,6 +1570,8 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
make_migration_entry_read(&entry);
newpmd = swp_entry_to_pmd(entry);
+ if (pmd_swp_soft_dirty(newpmd))
+ newpmd = pmd_swp_mksoft_dirty(newpmd);
set_pmd_at(mm, addr, pmd, newpmd);
}
goto unlock;
@@ -2408,7 +2424,8 @@ void set_pmd_migration_entry(struct page *page, struct vm_area_struct *vma,
set_page_dirty(page);
entry = make_migration_entry(page, pmd_write(pmdval));
pmdswp = swp_entry_to_pmd(entry);
- pmdswp = pmd_mkhuge(pmdswp);
+ if (pmd_soft_dirty(pmdval))
+ pmdswp = pmd_swp_mksoft_dirty(pmdswp);
set_pmd_at(mm, addr, pmd, pmdswp);
page_remove_rmap(page, true);
put_page(page);
@@ -2434,6 +2451,8 @@ void set_pmd_migration_entry(struct page *page, struct vm_area_struct *vma,
set_page_dirty(tmp);
entry = make_migration_entry(tmp, pte_write(pteval));
swp_pte = swp_entry_to_pte(entry);
+ if (pte_soft_dirty(pteval))
+ swp_pte = pte_swp_mksoft_dirty(swp_pte);
set_pte_at(mm, address, pte, swp_pte);
page_remove_rmap(tmp, false);
put_page(tmp);
@@ -2466,6 +2485,8 @@ int remove_migration_pmd(struct page *new, pmd_t *pmd,
goto unlock_ptl;
get_page(new);
pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot));
+ if (pmd_swp_soft_dirty(*pmd))
+ pmde = pmd_mksoft_dirty(pmde);
if (is_write_migration_entry(entry))
pmde = maybe_pmd_mkwrite(pmde, vma);
flush_cache_range(vma, mmun_start, mmun_end);
--
2.7.0
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