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

@@ -3292,31 +3292,34 @@ static void setup_pagelist_highmark(struct per_cpu_pageset *p,
 		pcp->batch = PAGE_SHIFT * 8;
 }
 
+static __meminit void setup_zone_pageset(struct zone *zone)
+{
+	int cpu;
+
+	zone->pageset = alloc_percpu(struct per_cpu_pageset);
+
+	for_each_possible_cpu(cpu) {
+		struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
+
+		setup_pageset(pcp, zone_batchsize(zone));
+
+		if (percpu_pagelist_fraction)
+			setup_pagelist_highmark(pcp,
+				(zone->present_pages /
+					percpu_pagelist_fraction));
+	}
+}
+
 /*
  * 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)
 {
 	struct zone *zone;
-	int cpu;
 
-	for_each_populated_zone(zone) {
-		zone->pageset = alloc_percpu(struct per_cpu_pageset);
-
-		for_each_possible_cpu(cpu) {
-			struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
-
-			setup_pageset(pcp, zone_batchsize(zone));
-
-			if (percpu_pagelist_fraction)
-				setup_pagelist_highmark(pcp,
-					(zone->present_pages /
-						percpu_pagelist_fraction));
-		}
-	}
+	for_each_populated_zone(zone)
+		setup_zone_pageset(zone);
 }
 
 static noinline __init_refok