--- arch/x86/mm/init_64.c

+++ arch/x86/mm/init_64.c

@@ -49,6 +49,7 @@

#include <asm/numa.h>

#include <asm/cacheflush.h>

#include <asm/init.h>

+#include <linux/bootmem.h>

static unsigned long dma_reserve __initdata;

@@ -615,6 +616,21 @@ void __init paging_init(void)

*/

#ifdef CONFIG_MEMORY_HOTPLUG

/*

+ * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need

+ * updating.

+ */

+static void update_end_of_memory_vars(u64 start, u64 size)

+{

+ unsigned long end_pfn = PFN_UP(start + size);

+

+ if (end_pfn > max_pfn) {

+ max_pfn = end_pfn;

+ max_low_pfn = end_pfn;

+ high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;

+ }

+}

+

+/*

* Memory is added always to NORMAL zone. This means you will never get

* additional DMA/DMA32 memory.

*/

@@ -633,6 +649,9 @@ int arch_add_memory(int nid, u64 start,

ret = __add_pages(nid, zone, start_pfn, nr_pages);

WARN_ON_ONCE(ret);

+ /* update max_pfn, max_low_pfn and high_memory */

+ update_end_of_memory_vars(start, size);

+

return ret;

}

EXPORT_SYMBOL_GPL(arch_add_memory);