mm: remove CONFIG_UNEVICTABLE_LRU config option

Currently, nobody wants to turn UNEVICTABLE_LRU off.  Thus this
configurability is unnecessary.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andi Kleen <andi@firstfloor.org>
Acked-by: Minchan Kim <minchan.kim@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/Kconfig b/mm/Kconfig
index 71830ba..97d2c88 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -203,25 +203,13 @@
 	def_bool y
 	depends on !ARCH_NO_VIRT_TO_BUS
 
-config UNEVICTABLE_LRU
-	bool "Add LRU list to track non-evictable pages"
-	default y
-	help
-	  Keeps unevictable pages off of the active and inactive pageout
-	  lists, so kswapd will not waste CPU time or have its balancing
-	  algorithms thrown off by scanning these pages.  Selecting this
-	  will use one page flag and increase the code size a little,
-	  say Y unless you know what you are doing.
-
-	  See Documentation/vm/unevictable-lru.txt for more information.
-
 config HAVE_MLOCK
 	bool
 	default y if MMU=y
 
 config HAVE_MLOCKED_PAGE_BIT
 	bool
-	default y if HAVE_MLOCK=y && UNEVICTABLE_LRU=y
+	default y if HAVE_MLOCK=y
 
 config MMU_NOTIFIER
 	bool