mm/page_alloc: fix incorrect PGFREE and PGALLOC for high-order page

PGFREE and PGALLOC represent the number of freed and allocated pages.  So
the page order must be considered.

Link: https://lkml.kernel.org/r/20221006101540.40686-1-laoar.shao@gmail.com
Fixes: 44042b44 ("mm/page_alloc: allow high-order pages to be stored on the per-cpu lists")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_alloc.c

@@ -3446,7 +3446,7 @@ static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp,
 	int pindex;
 	bool free_high;
 
-	__count_vm_event(PGFREE);
+	__count_vm_events(PGFREE, 1 << order);
 	pindex = order_to_pindex(migratetype, order);
 	list_add(&page->pcp_list, &pcp->lists[pindex]);
 	pcp->count += 1 << order;
@@ -3803,7 +3803,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone,
 	pcp_spin_unlock_irqrestore(pcp, flags);
 	pcp_trylock_finish(UP_flags);
 	if (page) {
-		__count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
+		__count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order);
 		zone_statistics(preferred_zone, zone, 1);
 	}
 	return page;