/*
* rmap interfaces called when adding or removing pte of page
*/
+void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
void page_add_file_rmap(struct page *);
page_cache_release(old_page);
}
reuse = reuse_swap_page(old_page);
+ if (reuse)
+ /*
+ * The page is all ours. Move it to our anon_vma so
+ * the rmap code will not search our parent or siblings.
+ * Protected against the rmap code by the page lock.
+ */
+ page_move_anon_rmap(old_page, vma, address);
unlock_page(old_page);
} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
(VM_WRITE|VM_SHARED))) {
}
EXPORT_SYMBOL_GPL(page_mkclean);
+/**
+ * page_move_anon_rmap - move a page to our anon_vma
+ * @page: the page to move to our anon_vma
+ * @vma: the vma the page belongs to
+ * @address: the user virtual address mapped
+ *
+ * When a page belongs exclusively to one process after a COW event,
+ * that page can be moved into the anon_vma that belongs to just that
+ * process, so the rmap code will not search the parent or sibling
+ * processes.
+ */
+void page_move_anon_rmap(struct page *page,
+ struct vm_area_struct *vma, unsigned long address)
+{
+ struct anon_vma *anon_vma = vma->anon_vma;
+
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!anon_vma);
+ VM_BUG_ON(page->index != linear_page_index(vma, address));
+
+ anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
+ page->mapping = (struct address_space *) anon_vma;
+}
+
/**
* __page_set_anon_rmap - setup new anonymous rmap
* @page: the page to add the mapping to