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/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 5739a34..e5e3486 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -637,6 +637,9 @@
 	extern u32 dtcm_end;
 	extern u32 itcm_end;
 #endif
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+	struct zone *zone;
+#endif
 
 	max_mapnr   = pfn_to_page(max_pfn + PHYS_PFN_OFFSET) - mem_map;
 
@@ -682,6 +685,14 @@
 #endif
 	}
 
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+	for_each_zone(zone) {
+		if (zone_idx(zone) == ZONE_MOVABLE)
+			total_unmovable_pages = totalram_pages -
+							zone->spanned_pages;
+	}
+#endif
+
 	/*
 	 * Since our memory may not be contiguous, calculate the
 	 * real number of pages we have in this system
@@ -784,6 +795,7 @@
 
 void free_initmem(void)
 {
+	unsigned long reclaimed_initmem;
 #ifdef CONFIG_HAVE_TCM
 	extern char __tcm_start, __tcm_end;
 
@@ -792,10 +804,15 @@
 				    "TCM link");
 #endif
 
-	if (!machine_is_integrator() && !machine_is_cintegrator())
-		totalram_pages += free_area(__phys_to_pfn(__pa(__init_begin)),
+	if (!machine_is_integrator() && !machine_is_cintegrator()) {
+		reclaimed_initmem = free_area(__phys_to_pfn(__pa(__init_begin)),
 					    __phys_to_pfn(__pa(__init_end)),
 					    "init");
+		totalram_pages += reclaimed_initmem;
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+		total_unmovable_pages += reclaimed_initmem;
+#endif
+	}
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG
@@ -831,10 +848,16 @@
 
 void free_initrd_mem(unsigned long start, unsigned long end)
 {
-	if (!keep_initrd)
-		totalram_pages += free_area(__phys_to_pfn(__pa(start)),
+	unsigned long reclaimed_initrd_mem;
+	if (!keep_initrd) {
+		reclaimed_initrd_mem = free_area(__phys_to_pfn(__pa(start)),
 					    __phys_to_pfn(__pa(end)),
 					    "initrd");
+		totalram_pages += reclaimed_initrd_mem;
+#ifdef CONFIG_FIX_MOVABLE_ZONE
+		total_unmovable_pages += reclaimed_initrd_mem;
+#endif
+	}
 }
 
 static int __init keepinitrd_setup(char *__unused)