mem-hotplug: separate setup_per_cpu_pageset() into separate functions

No behavior change here.

Move some of setup_per_cpu_pageset() code into a new function
setup_zone_pageset() that will be useful for memory hotplug.
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NHaicheng Li <haicheng.li@linux.intel.com>
Reviewed-by: NAndi Kleen <andi.kleen@intel.com>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -3292,18 +3292,10 @@ static void setup_pagelist_highmark(struct per_cpu_pageset *p,
 		pcp->batch = PAGE_SHIFT * 8;
 }
 
-/*
- * Allocate per cpu pagesets and initialize them.
- * Before this call only boot pagesets were available.
- * Boot pagesets will no longer be used by this processorr
- * after setup_per_cpu_pageset().
- */
-void __init setup_per_cpu_pageset(void)
+static __meminit void setup_zone_pageset(struct zone *zone)
 {
-	struct zone *zone;
 	int cpu;
 
-	for_each_populated_zone(zone) {
 	zone->pageset = alloc_percpu(struct per_cpu_pageset);
 
 	for_each_possible_cpu(cpu) {
@@ -3316,7 +3308,18 @@ void __init setup_per_cpu_pageset(void)
 				(zone->present_pages /
 					percpu_pagelist_fraction));
 	}
-	}
+}
+
+/*
+ * Allocate per cpu pagesets and initialize them.
+ * Before this call only boot pagesets were available.
+ */
+void __init setup_per_cpu_pageset(void)
+{
+	struct zone *zone;
+
+	for_each_populated_zone(zone)
+		setup_zone_pageset(zone);
 }
 
 static noinline __init_refok