[PATCH] Swapless page migration: add R/W migration entries

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

diff --git a/mm/rmap.c b/mm/rmap.c
index 10806b7af40c0a111c544e0635dd31fb24b10809..3b8ce86daa3a6600845d78174a5506b8fe738166 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -103,7 +103,7 @@ int anon_vma_prepare(struct vm_area_struct *vma)
                spin_lock(&mm->page_table_lock);
                if (likely(!vma->anon_vma)) {
                        vma->anon_vma = anon_vma;
-                       list_add(&vma->anon_vma_node, &anon_vma->head);
+                       list_add_tail(&vma->anon_vma_node, &anon_vma->head);
                        allocated = NULL;
                }
                spin_unlock(&mm->page_table_lock);
@@ -127,7 +127,7 @@ void __anon_vma_link(struct vm_area_struct *vma)
        struct anon_vma *anon_vma = vma->anon_vma;
 
        if (anon_vma) {
-               list_add(&vma->anon_vma_node, &anon_vma->head);
+               list_add_tail(&vma->anon_vma_node, &anon_vma->head);
                validate_anon_vma(vma);
        }
 }
@@ -138,7 +138,7 @@ void anon_vma_link(struct vm_area_struct *vma)
 
        if (anon_vma) {
                spin_lock(&anon_vma->lock);
-               list_add(&vma->anon_vma_node, &anon_vma->head);
+               list_add_tail(&vma->anon_vma_node, &anon_vma->head);
                validate_anon_vma(vma);
                spin_unlock(&anon_vma->lock);
        }
@@ -620,17 +620,27 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
 
        if (PageAnon(page)) {
                swp_entry_t entry = { .val = page_private(page) };
-               /*
-                * Store the swap location in the pte.
-                * See handle_pte_fault() ...
-                */
-               BUG_ON(!PageSwapCache(page));
-               swap_duplicate(entry);
-               if (list_empty(&mm->mmlist)) {
-                       spin_lock(&mmlist_lock);
-                       if (list_empty(&mm->mmlist))
-                               list_add(&mm->mmlist, &init_mm.mmlist);
-                       spin_unlock(&mmlist_lock);
+
+               if (PageSwapCache(page)) {
+                       /*
+                        * Store the swap location in the pte.
+                        * See handle_pte_fault() ...
+                        */
+                       swap_duplicate(entry);
+                       if (list_empty(&mm->mmlist)) {
+                               spin_lock(&mmlist_lock);
+                               if (list_empty(&mm->mmlist))
+                                       list_add(&mm->mmlist, &init_mm.mmlist);
+                               spin_unlock(&mmlist_lock);
+                       }
+               } else {
+                       /*
+                        * Store the pfn of the page in a special migration
+                        * pte. do_swap_page() will wait until the migration
+                        * pte is removed and then restart fault handling.
+                        */
+                       BUG_ON(!migration);
+                       entry = make_migration_entry(page, pte_write(pteval));
                }
                set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
                BUG_ON(pte_file(*pte));