From ab6e3d0939bb332d72444a532f0f72e0dfde7b7b Mon Sep 17 00:00:00 2001
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Date: Fri, 8 Sep 2017 16:11:04 -0700
Subject: mm: soft-dirty: keep soft-dirty bits over thp migration

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@ah.jp.nec.com>
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 include/asm-generic/pgtable.h | 34 +++++++++++++++++++++++++++++++++-
 include/linux/swapops.h       |  2 ++
 2 files changed, 35 insertions(+), 1 deletion(-)

(limited to 'include')

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 4f93a6d10a47..8e0243036564 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -630,7 +630,24 @@ 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;
@@ -675,6 +692,21 @@ 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 82089fd88c29..45b092aa6419 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -183,6 +183,8 @@ 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));
 }
-- 
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