mm: Add total_unmovable_pages global variable

Vmalloc will exit if the amount it needs to allocate is
greater than totalram_pages. Vmalloc cannot allocate
from the movable zone, so pages in the movable zone should
not be counted.

This change adds a new global variable: total_unmovable_pages.
It is calculated in init.c, based on totalram_pages minus
the pages in the movable zone. Vmalloc now looks at this new
global instead of totalram_pages.

total_unmovable_pages can be modified during memory_hotplug.
If the zone you are offlining/onlining is unmovable, then
you modify it similar to totalram_pages.  If the zone is
movable, then no change is needed.

Change-Id: Ie55c41051e9ad4b921eb04ecbb4798a8bd2344d6
Signed-off-by: Jack Cheung <jackc@codeaurora.org>
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index faf318e..70ea0df 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -379,6 +379,10 @@
 	unsigned long pfn = page_to_pfn(page);
 
 	totalram_pages++;
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+	if (zone_idx(page_zone(page)) != ZONE_MOVABLE)
+		total_unmovable_pages++;
+#endif
 	if (pfn >= num_physpages)
 		num_physpages = pfn + 1;
 
@@ -965,6 +969,10 @@
 	zone->zone_pgdat->node_present_pages -= offlined_pages;
 	totalram_pages -= offlined_pages;
 
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+	if (zone_idx(zone) != ZONE_MOVABLE)
+		total_unmovable_pages -= offlined_pages;
+#endif
 	init_per_zone_wmark_min();
 
 	if (!node_present_pages(node)) {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5489c43..60ad5e9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -96,6 +96,9 @@
 
 unsigned long totalram_pages __read_mostly;
 unsigned long totalreserve_pages __read_mostly;
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+unsigned long total_unmovable_pages __read_mostly;
+#endif
 int percpu_pagelist_fraction;
 gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
 
@@ -174,6 +177,9 @@
 };
 
 EXPORT_SYMBOL(totalram_pages);
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+EXPORT_SYMBOL(total_unmovable_pages);
+#endif
 
 static char * const zone_names[MAX_NR_ZONES] = {
 #ifdef CONFIG_ZONE_DMA
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 45ece89..c33d2ae 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1611,9 +1611,14 @@
 	struct vm_struct *area;
 	void *addr;
 	unsigned long real_size = size;
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+	unsigned long total_pages = total_unmovable_pages;
+#else
+	unsigned long total_pages = totalram_pages;
+#endif
 
 	size = PAGE_ALIGN(size);
-	if (!size || (size >> PAGE_SHIFT) > totalram_pages)
+	if (!size || (size >> PAGE_SHIFT) > total_pages)
 		return NULL;
 
 	area = __get_vm_area_node(size, align, VM_ALLOC, start, end, node,