mm/page_alloc: in zone_pcp_update(), uze zone_pageset_init()

Previously, zone_pcp_update() called pageset_set_batch() directly,
essentially assuming that percpu_pagelist_fraction == 0.

Correct this by calling zone_pageset_init(), which chooses the
appropriate ->batch and ->high calculations.
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -6098,11 +6098,9 @@ void free_contig_range(unsigned long pfn, unsigned nr_pages)
 void __meminit zone_pcp_update(struct zone *zone)
 {
 	unsigned cpu;
-	unsigned long batch;
 	mutex_lock(&pcp_batch_high_lock);
-	batch = zone_batchsize(zone);
 	for_each_possible_cpu(cpu)
-		pageset_set_batch(per_cpu_ptr(zone->pageset, cpu), batch);
+		zone_pageset_init(zone, cpu);
 	mutex_unlock(&pcp_batch_high_lock);
 }
 #endif