diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 259e9ea..bb28c97 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -107,7 +107,9 @@
 
 /* These are exported to sysctl. */
 extern int dirty_background_ratio;
+extern unsigned long dirty_background_bytes;
 extern int vm_dirty_ratio;
+extern unsigned long vm_dirty_bytes;
 extern int dirty_writeback_interval;
 extern int dirty_expire_interval;
 extern int vm_highmem_is_dirtyable;
@@ -116,9 +118,18 @@
 
 extern unsigned long determine_dirtyable_memory(void);
 
+extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
+		struct file *filp, void __user *buffer, size_t *lenp,
+		loff_t *ppos);
+extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
+		struct file *filp, void __user *buffer, size_t *lenp,
+		loff_t *ppos);
 extern int dirty_ratio_handler(struct ctl_table *table, int write,
 		struct file *filp, void __user *buffer, size_t *lenp,
 		loff_t *ppos);
+extern int dirty_bytes_handler(struct ctl_table *table, int write,
+		struct file *filp, void __user *buffer, size_t *lenp,
+		loff_t *ppos);
 
 struct ctl_table;
 struct file;