diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 93d2c79..dece6bd 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -350,6 +350,14 @@ config ACPI_HOTPLUG_MEMORY
 	  To compile this driver as a module, choose M here:
 	  the module will be called acpi_memhotplug.
 
+config ACPI_HOTPLUG_MEMORY_AUTO_ONLINE
+	bool "Automatically online hotplugged memory"
+	depends on ACPI_HOTPLUG_MEMORY
+	default n
+	help
+	  This forces memory that is brought into service by ACPI
+	  to be automatically onlined.
+
 config ACPI_SBS
 	tristate "Smart Battery System"
 	depends on X86
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index d985713..5af0bdc 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -31,6 +31,9 @@
 #include <linux/types.h>
 #include <linux/memory_hotplug.h>
 #include <linux/slab.h>
+#ifdef CONFIG_ACPI_HOTPLUG_MEMORY_AUTO_ONLINE
+#include <linux/memory.h>
+#endif
 #include <acpi/acpi_drivers.h>
 
 #define ACPI_MEMORY_DEVICE_CLASS		"memory"
@@ -46,6 +49,11 @@ ACPI_MODULE_NAME("acpi_memhotplug");
 MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>");
 MODULE_DESCRIPTION("Hotplug Mem Driver");
 MODULE_LICENSE("GPL");
+#ifdef CONFIG_ACPI_HOTPLUG_MEMORY_AUTO_ONLINE
+static int mem_hotadd_auto = 1;
+module_param(mem_hotadd_auto, bool, 0444);
+MODULE_PARM_DESC(mem_hotadd_auto, "Disable automatic onlining of memory");
+#endif
 
 /* Memory Device States */
 #define MEMORY_INVALID_STATE	0
@@ -219,6 +227,9 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 	int result, num_enabled = 0;
 	struct acpi_memory_info *info;
 	int node;
+#ifdef CONFIG_ACPI_HOTPLUG_MEMORY_AUTO_ONLINE
+	u64 err_addr;
+#endif
 
 
 	/* Get the range from the _CRS */
@@ -253,6 +264,19 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 		result = add_memory(node, info->start_addr, info->length);
 		if (result)
 			continue;
+#ifdef CONFIG_ACPI_HOTPLUG_MEMORY_AUTO_ONLINE
+		if (mem_hotadd_auto) {
+			err_addr = set_memory_state(info->start_addr >>
+						    PAGE_SHIFT,
+						    info->length >> PAGE_SHIFT,
+						    MEM_ONLINE, MEM_OFFLINE);
+			if (err_addr)
+				printk(KERN_ERR PREFIX "Memory online failed "
+				       "for 0x%llx - 0x%llx\n",
+				       err_addr << PAGE_SHIFT,
+				       info->start_addr + info->length);
+		}
+#endif
 		info->enabled = 1;
 		num_enabled++;
 	}
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 933442f..f2a5c19 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -516,6 +516,41 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
 }
 
 /*
+ * need an interface for the VM to mark sections on and offline when
+ * hot-swapping memory.
+ *
+ * Returns 0 on success, or the failing pfn on failure.
+ */
+u64 set_memory_state(unsigned long start_pfn, unsigned long nr_pages,
+		     unsigned long to_state, unsigned long from_state_req)
+{
+	struct mem_section *section;
+	struct memory_block *mem;
+	unsigned long start_sec, end_sec, i, current_pfn;
+	int ret = 0;
+
+	start_sec = pfn_to_section_nr(start_pfn);
+	end_sec = pfn_to_section_nr(start_pfn + nr_pages - 1);
+	for (i = start_sec; i <= end_sec; i++) {
+		if (valid_section_nr(i) && present_section_nr(i)) {
+			section = __nr_to_section(i);
+			mem = find_memory_block(section);
+			ret = memory_block_change_state(mem, to_state,
+							from_state_req);
+			if (ret) {
+				current_pfn = section_nr_to_pfn(start_sec);
+				printk(KERN_WARNING "memory (0x%0lx - 0x%0lx) "
+				       "online failed.", current_pfn,
+				       current_pfn + PAGES_PER_SECTION);
+				return current_pfn;
+			}
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(set_memory_state);
+
+/*
  * need an interface for the VM to add new memory regions,
  * but without onlining it.
  */
diff --git a/include/linux/memory.h b/include/linux/memory.h
index 85582e1..57b8760 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -114,6 +114,8 @@ extern int remove_memory_block(unsigned long, struct mem_section *, int);
 extern int memory_notify(unsigned long val, void *v);
 extern int memory_isolate_notify(unsigned long val, void *v);
 extern struct memory_block *find_memory_block(struct mem_section *);
+extern u64 set_memory_state(unsigned long, unsigned long, unsigned long,
+			    unsigned long);
 #define CONFIG_MEM_BLOCK_SIZE	(PAGES_PER_SECTION<<PAGE_SHIFT)
 enum mem_add_context { BOOT, HOTPLUG };
 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
