1 files changed, 10 insertions, 2 deletions

diff --git a/mm/mremap.c b/mm/mremap.c
index 318eea5467a0..ccf456477020 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -167,6 +167,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
         unsigned long new_pgoff;
         unsigned long moved_len;
         unsigned long excess = 0;
+        unsigned long hiwater_vm;
         int split = 0;
 
         /*
@@ -205,9 +206,15 @@ static unsigned long move_vma(struct vm_area_struct *vma,
         }
 
         /*
-         * if we failed to move page tables we still do total_vm increment
-         * since do_munmap() will decrement it by old_len == new_len
+         * If we failed to move page tables we still do total_vm increment
+         * since do_munmap() will decrement it by old_len == new_len.
+         *
+         * Since total_vm is about to be raised artificially high for a
+         * moment, we need to restore high watermark afterwards: if stats
+         * are taken meanwhile, total_vm and hiwater_vm appear too high.
+         * If this were a serious issue, we'd add a flag to do_munmap().
          */
+        hiwater_vm = mm->hiwater_vm;
         mm->total_vm += new_len >> PAGE_SHIFT;
         vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
 
@@ -216,6 +223,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
                 vm_unacct_memory(excess >> PAGE_SHIFT);
                 excess = 0;
         }
+        mm->hiwater_vm = hiwater_vm;
 
         /* Restore VM_ACCOUNT if one or two pieces of vma left */
         if (excess) {