[PATCH] mm: update_hiwaters just in time

[linux-2.6-block.git] / mm / mremap.c

diff --git a/mm/mremap.c b/mm/mremap.c
index 318eea5467a05bac295b8723cf6e0b216becef02..ccf456477020a2db2b1baa56eaf418436450a7a2 100644 (file)
--- 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) {