uml: shrink kernel stacks

Make kernel stacks be 1 page on i386 and 2 pages on x86_64.  These match the
host values.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/Kconfig

@@ -277,7 +277,8 @@ config HIGHMEM
 
 config KERNEL_STACK_ORDER
 	int "Kernel stack size order"
-	default 2
+	default 1 if 64BIT
+	default 0 if !64BIT
 	help
 	This option determines the size of UML kernel stacks.  They will
 	be 1 << order pages.  The default is OK unless you're running Valgrind

arch/um/defconfig

@@ -86,7 +86,7 @@ CONFIG_MCONSOLE=y
 # CONFIG_MAGIC_SYSRQ is not set
 CONFIG_NEST_LEVEL=0
 # CONFIG_HIGHMEM is not set
-CONFIG_KERNEL_STACK_ORDER=2
+CONFIG_KERNEL_STACK_ORDER=0
 CONFIG_UML_REAL_TIME_CLOCK=y
 
 #