3 files changed, 25 insertions, 2 deletions

diff --git a/Documentation/vm/pagemap.txt b/Documentation/vm/pagemap.txt
index 6bfbc172cdb9..56faec0f73f7 100644
--- a/Documentation/vm/pagemap.txt
+++ b/Documentation/vm/pagemap.txt
@@ -16,7 +16,8 @@ There are three components to pagemap:
     * Bits 0-4   swap type if swapped
     * Bits 5-54  swap offset if swapped
     * Bit  55    pte is soft-dirty (see Documentation/vm/soft-dirty.txt)
-    * Bits 56-60 zero
+    * Bit  56    page exclusively mapped
+    * Bits 57-60 zero
     * Bit  61    page is file-page or shared-anon
     * Bit  62    page swapped
     * Bit  63    page present
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index bc651644b1b2..67c76468a7be 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -949,6 +949,7 @@ struct pagemapread {
 #define PM_PFRAME_BITS          55
 #define PM_PFRAME_MASK          GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
 #define PM_SOFT_DIRTY           BIT_ULL(55)
+#define PM_MMAP_EXCLUSIVE       BIT_ULL(56)
 #define PM_FILE                 BIT_ULL(61)
 #define PM_SWAP                 BIT_ULL(62)
 #define PM_PRESENT              BIT_ULL(63)
@@ -1036,6 +1037,8 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
 
         if (page && !PageAnon(page))
                 flags |= PM_FILE;
+        if (page && page_mapcount(page) == 1)
+                flags |= PM_MMAP_EXCLUSIVE;
         if (vma->vm_flags & VM_SOFTDIRTY)
                 flags |= PM_SOFT_DIRTY;
 
@@ -1066,6 +1069,11 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
                  * This if-check is just to prepare for future implementation.
                  */
                 if (pmd_present(pmd)) {
+                        struct page *page = pmd_page(pmd);
+
+                        if (page_mapcount(page) == 1)
+                                flags |= PM_MMAP_EXCLUSIVE;
+
                         flags |= PM_PRESENT;
                         if (pm->show_pfn)
                                 frame = pmd_pfn(pmd) +
@@ -1131,6 +1139,9 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
                 if (!PageAnon(page))
                         flags |= PM_FILE;
 
+                if (page_mapcount(page) == 1)
+                        flags |= PM_MMAP_EXCLUSIVE;
+
                 flags |= PM_PRESENT;
                 if (pm->show_pfn)
                         frame = pte_pfn(pte) +
@@ -1163,7 +1174,8 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
  * Bits 0-4   swap type if swapped
  * Bits 5-54  swap offset if swapped
  * Bit  55    pte is soft-dirty (see Documentation/vm/soft-dirty.txt)
- * Bits 56-60 zero
+ * Bit  56    page exclusively mapped
+ * Bits 57-60 zero
  * Bit  61    page is file-page or shared-anon
  * Bit  62    page swapped
  * Bit  63    page present
diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
index 603ec916716b..7f73fa32a590 100644
--- a/tools/vm/page-types.c
+++ b/tools/vm/page-types.c
@@ -62,6 +62,7 @@
 #define PM_PFRAME_MASK          ((1LL << PM_PFRAME_BITS) - 1)
 #define PM_PFRAME(x)            ((x) & PM_PFRAME_MASK)
 #define PM_SOFT_DIRTY           (1ULL << 55)
+#define PM_MMAP_EXCLUSIVE       (1ULL << 56)
 #define PM_FILE                 (1ULL << 61)
 #define PM_SWAP                 (1ULL << 62)
 #define PM_PRESENT              (1ULL << 63)
@@ -91,6 +92,8 @@
 #define KPF_SLOB_FREE           49
 #define KPF_SLUB_FROZEN         50
 #define KPF_SLUB_DEBUG          51
+#define KPF_FILE                62
+#define KPF_MMAP_EXCLUSIVE      63
 
 #define KPF_ALL_BITS            ((uint64_t)~0ULL)
 #define KPF_HACKERS_BITS        (0xffffULL << 32)
@@ -140,6 +143,9 @@ static const char * const page_flag_names[] = {
         [KPF_SLOB_FREE]         = "P:slob_free",
         [KPF_SLUB_FROZEN]       = "A:slub_frozen",
         [KPF_SLUB_DEBUG]        = "E:slub_debug",
+
+        [KPF_FILE]              = "F:file",
+        [KPF_MMAP_EXCLUSIVE]    = "1:mmap_exclusive",
 };
 
 
@@ -443,6 +449,10 @@ static uint64_t expand_overloaded_flags(uint64_t flags, uint64_t pme)
 
         if (pme & PM_SOFT_DIRTY)
                 flags |= BIT(SOFTDIRTY);
+        if (pme & PM_FILE)
+                flags |= BIT(FILE);
+        if (pme & PM_MMAP_EXCLUSIVE)
+                flags |= BIT(MMAP_EXCLUSIVE);
 
         return flags;
 }