mm: restore zone->all_unreclaimable to independence word

commit e815af95 ("change all_unreclaimable zone member to flags") changed
all_unreclaimable member to bit flag.  But it had an undesireble side
effect.  free_one_page() is one of most hot path in linux kernel and
increasing atomic ops in it can reduce kernel performance a bit.

Thus, this patch revert such commit partially. at least
all_unreclaimable shouldn't share memory word with other zone flags.

[akpm@linux-foundation.org: fix patch interaction]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmstat.c b/mm/vmstat.c
index fc5aa18..7f760cb 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -763,7 +763,7 @@
 		   "\n  prev_priority:     %i"
 		   "\n  start_pfn:         %lu"
 		   "\n  inactive_ratio:    %u",
-			   zone_is_all_unreclaimable(zone),
+		   zone->all_unreclaimable,
 		   zone->prev_priority,
 		   zone->zone_start_pfn,
 		   zone->inactive_ratio);