X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=mm%2Fmigrate.c;h=2a80136b23bbc16fb9d2ec2fad932b29e30dda50;hb=6ee6c6adf1cfebbf432b8d1f204c7f96e395933e;hp=e7d13a708da0b5ea4571993f85e44c9f5c0c6876;hpb=4f5ca265788973e3f5a1129a96ee4a9cbf587f2b;p=linux-2.6-omap-h63xx.git

diff --git a/mm/migrate.c b/mm/migrate.c
index e7d13a708da..2a80136b23b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -285,7 +285,15 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
 
 	page = migration_entry_to_page(entry);
 
-	get_page(page);
+	/*
+	 * Once radix-tree replacement of page migration started, page_count
+	 * *must* be zero. And, we don't want to call wait_on_page_locked()
+	 * against a page without get_page().
+	 * So, we use get_page_unless_zero(), here. Even failed, page fault
+	 * will occur again.
+	 */
+	if (!get_page_unless_zero(page))
+		goto out;
 	pte_unmap_unlock(ptep, ptl);
 	wait_on_page_locked(page);
 	put_page(page);
@@ -305,6 +313,7 @@ out:
 static int migrate_page_move_mapping(struct address_space *mapping,
 		struct page *newpage, struct page *page)
 {
+	int expected_count;
 	void **pslot;
 
 	if (!mapping) {
@@ -314,14 +323,20 @@ static int migrate_page_move_mapping(struct address_space *mapping,
 		return 0;
 	}
 
-	write_lock_irq(&mapping->tree_lock);
+	spin_lock_irq(&mapping->tree_lock);
 
 	pslot = radix_tree_lookup_slot(&mapping->page_tree,
  					page_index(page));
 
-	if (page_count(page) != 2 + !!PagePrivate(page) ||
+	expected_count = 2 + !!PagePrivate(page);
+	if (page_count(page) != expected_count ||
 			(struct page *)radix_tree_deref_slot(pslot) != page) {
-		write_unlock_irq(&mapping->tree_lock);
+		spin_unlock_irq(&mapping->tree_lock);
+		return -EAGAIN;
+	}
+
+	if (!page_freeze_refs(page, expected_count)) {
+		spin_unlock_irq(&mapping->tree_lock);
 		return -EAGAIN;
 	}
 
@@ -338,6 +353,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
 
 	radix_tree_replace_slot(pslot, newpage);
 
+	page_unfreeze_refs(page, expected_count);
 	/*
 	 * Drop cache reference from old page.
 	 * We know this isn't the last reference.
@@ -357,7 +373,9 @@ static int migrate_page_move_mapping(struct address_space *mapping,
 	__dec_zone_page_state(page, NR_FILE_PAGES);
 	__inc_zone_page_state(newpage, NR_FILE_PAGES);
 
-	write_unlock_irq(&mapping->tree_lock);
+	spin_unlock_irq(&mapping->tree_lock);
+	if (!PageSwapCache(newpage))
+		mem_cgroup_uncharge_cache_page(page);
 
 	return 0;
 }
@@ -587,7 +605,7 @@ static int move_to_new_page(struct page *newpage, struct page *page)
 	 * establishing additional references. We are the only one
 	 * holding a reference to the new page at this point.
 	 */
-	if (TestSetPageLocked(newpage))
+	if (!trylock_page(newpage))
 		BUG();
 
 	/* Prepare mapping for the new page.*/
@@ -611,7 +629,6 @@ static int move_to_new_page(struct page *newpage, struct page *page)
 		rc = fallback_migrate_page(mapping, newpage, page);
 
 	if (!rc) {
-		mem_cgroup_page_migration(page, newpage);
 		remove_migration_ptes(page, newpage);
 	} else
 		newpage->mapping = NULL;
@@ -641,8 +658,16 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
 		/* page was freed from under us. So we are done. */
 		goto move_newpage;
 
+	charge = mem_cgroup_prepare_migration(page, newpage);
+	if (charge == -ENOMEM) {
+		rc = -ENOMEM;
+		goto move_newpage;
+	}
+	/* prepare cgroup just returns 0 or -ENOMEM */
+	BUG_ON(charge);
+
 	rc = -EAGAIN;
-	if (TestSetPageLocked(page)) {
+	if (!trylock_page(page)) {
 		if (!force)
 			goto move_newpage;
 		lock_page(page);
@@ -692,19 +717,14 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
 		goto rcu_unlock;
 	}
 
-	charge = mem_cgroup_prepare_migration(page);
 	/* Establish migration ptes or remove ptes */
 	try_to_unmap(page, 1);
 
 	if (!page_mapped(page))
 		rc = move_to_new_page(newpage, page);
 
-	if (rc) {
+	if (rc)
 		remove_migration_ptes(page, page);
-		if (charge)
-			mem_cgroup_end_migration(page);
-	} else if (charge)
- 		mem_cgroup_end_migration(newpage);
 rcu_unlock:
 	if (rcu_locked)
 		rcu_read_unlock();
@@ -725,6 +745,8 @@ unlock:
 	}
 
 move_newpage:
+	if (!charge)
+		mem_cgroup_end_migration(newpage);
 	/*
 	 * Move the new page to the LRU. If migration was not successful
 	 * then this will free the page.
@@ -1071,7 +1093,6 @@ out2:
 	mmput(mm);
 	return err;
 }
-#endif
 
 /*
  * Call migration functions in the vma_ops that may prepare
@@ -1093,3 +1114,4 @@ int migrate_vmas(struct mm_struct *mm, const nodemask_t *to,
  	}
  	return err;
 }
+#endif