thp: mremap support and TLB optimization

[pandora-kernel.git] / mm / huge_memory.c

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e2d1587..6b072bd 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1052,6 +1052,51 @@ int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
        return ret;
 }
 
+int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
+                 unsigned long old_addr,
+                 unsigned long new_addr, unsigned long old_end,
+                 pmd_t *old_pmd, pmd_t *new_pmd)
+{
+       int ret = 0;
+       pmd_t pmd;
+
+       struct mm_struct *mm = vma->vm_mm;
+
+       if ((old_addr & ~HPAGE_PMD_MASK) ||
+           (new_addr & ~HPAGE_PMD_MASK) ||
+           old_end - old_addr < HPAGE_PMD_SIZE ||
+           (new_vma->vm_flags & VM_NOHUGEPAGE))
+               goto out;
+
+       /*
+        * The destination pmd shouldn't be established, free_pgtables()
+        * should have release it.
+        */
+       if (WARN_ON(!pmd_none(*new_pmd))) {
+               VM_BUG_ON(pmd_trans_huge(*new_pmd));
+               goto out;
+       }
+
+       spin_lock(&mm->page_table_lock);
+       if (likely(pmd_trans_huge(*old_pmd))) {
+               if (pmd_trans_splitting(*old_pmd)) {
+                       spin_unlock(&mm->page_table_lock);
+                       wait_split_huge_page(vma->anon_vma, old_pmd);
+                       ret = -1;
+               } else {
+                       pmd = pmdp_get_and_clear(mm, old_addr, old_pmd);
+                       VM_BUG_ON(!pmd_none(*new_pmd));
+                       set_pmd_at(mm, new_addr, new_pmd, pmd);
+                       spin_unlock(&mm->page_table_lock);
+                       ret = 1;
+               }
+       } else {
+               spin_unlock(&mm->page_table_lock);
+       }
+out:
+       return ret;
+}
+
 int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
                unsigned long addr, pgprot_t newprot)
 {