diff --git a/[refs] b/[refs]
index e4a33007678f..c8355751322e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: aa24411b6717fd1e6ecef281bec497f6f30bbd66
+refs/heads/master: b1cbf9b1d6af22ba262d99abcfd71d5d90dbd57a
diff --git a/trunk/drivers/xen/balloon.c b/trunk/drivers/xen/balloon.c
index 4f59fb373381..9efb993090aa 100644
--- a/trunk/drivers/xen/balloon.c
+++ b/trunk/drivers/xen/balloon.c
@@ -586,16 +586,16 @@ static int __init balloon_init(void)
 #endif
 
 	/*
-	 * Initialise the balloon with excess memory space.  We need
-	 * to make sure we don't add memory which doesn't exist or
-	 * logically exist.  The E820 map can be trimmed to be smaller
-	 * than the amount of physical memory due to the mem= command
-	 * line parameter.  And if this is a 32-bit non-HIGHMEM kernel
-	 * on a system with memory which requires highmem to access,
-	 * don't try to use it.
+	 * Initialize the balloon with pages from the extra memory
+	 * region (see arch/x86/xen/setup.c).
+	 *
+	 * If the amount of usable memory has been limited (e.g., with
+	 * the 'mem' command line parameter), don't add pages beyond
+	 * this limit.
 	 */
-	extra_pfn_end = min(min(max_pfn, e820_end_of_ram_pfn()),
-			    (unsigned long)PFN_DOWN(xen_extra_mem_start + xen_extra_mem_size));
+	extra_pfn_end = min(max_pfn,
+			    (unsigned long)PFN_DOWN(xen_extra_mem_start
+						    + xen_extra_mem_size));
 	for (pfn = PFN_UP(xen_extra_mem_start);
 	     pfn < extra_pfn_end;
 	     pfn++) {