From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
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 1
- clear_soft_dirty_pmd can handle migration entry
---
arch/x86/include/asm/pgtable.h | 17 +++++++++++++++++
fs/proc/task_mmu.c | 27 ++++++++++++++++-----------
include/asm-generic/pgtable.h | 34 +++++++++++++++++++++++++++++++++-
include/linux/swapops.h | 2 ++
mm/huge_memory.c | 22 +++++++++++++++++++++-
5 files changed, 89 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1cfb36b8c024..e57abf8e926c 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1088,6 +1088,23 @@ 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 a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index f2b0f3ba25ac..6ea9546ea8c1 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -908,17 +908,22 @@ static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
{
pmd_t pmd = *pmdp;
- /* See comment in change_huge_pmd() */
- pmdp_invalidate(vma, addr, pmdp);
- if (pmd_dirty(*pmdp))
- pmd = pmd_mkdirty(pmd);
- if (pmd_young(*pmdp))
- pmd = pmd_mkyoung(pmd);
-
- pmd = pmd_wrprotect(pmd);
- pmd = pmd_clear_soft_dirty(pmd);
-
- set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+ if (pmd_present(pmd)) {
+ /* See comment in change_huge_pmd() */
+ pmdp_invalidate(vma, addr, pmdp);
+ if (pmd_dirty(*pmdp))
+ pmd = pmd_mkdirty(pmd);
+ if (pmd_young(*pmdp))
+ pmd = pmd_mkyoung(pmd);
+
+ 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 a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index f98a028100b6..7c781aef0911 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -574,7 +574,24 @@ 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;
@@ -619,6 +636,21 @@ 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 a/include/linux/swapops.h b/include/linux/swapops.h
index 6625bea13869..b52674bd4173 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -179,6 +179,8 @@ 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 a/mm/huge_memory.c b/mm/huge_memory.c
index 3f18452f3eb1..f8a11d634a7e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -905,6 +905,8 @@ 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);
@@ -1707,6 +1709,17 @@ static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl,
}
#endif
+static pmd_t move_soft_dirty_pmd(pmd_t pmd)
+{
+#ifdef CONFIG_MEM_SOFT_DIRTY
+ if (unlikely(is_pmd_migration_entry(pmd)))
+ pmd = pmd_swp_mksoft_dirty(pmd);
+ else if (pmd_present(pmd))
+ pmd = pmd_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, bool *need_flush)
@@ -1749,7 +1762,8 @@ 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);
if (force_flush)
@@ -2751,6 +2765,8 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
set_page_dirty(page);
entry = make_migration_entry(page, pmd_write(pmdval));
pmdswp = swp_entry_to_pmd(entry);
+ if (pmd_soft_dirty(pmdval))
+ pmdswp = pmd_swp_mksoft_dirty(pmdswp);
set_pmd_at(mm, address, pvmw->pmd, pmdswp);
page_remove_rmap(page, true);
put_page(page);
@@ -2767,6 +2783,8 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
set_page_dirty(subpage);
entry = make_migration_entry(subpage, 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, pvmw->pte, swp_pte);
page_remove_rmap(subpage, false);
put_page(subpage);
@@ -2790,6 +2808,8 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
entry = pmd_to_swp_entry(*pvmw->pmd);
get_page(new);
pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot));
+ if (pmd_swp_soft_dirty(*pvmw->pmd))
+ pmde = pmd_mksoft_dirty(pmde);
if (is_write_migration_entry(entry))
pmde = maybe_pmd_mkwrite(pmde, vma);
--
2.11.0
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
