x86: require x86-64 for automatic NUMA balancing

32-bit support for NUMA is an oddity on its own but with automatic NUMA
balancing on top there is a reasonable risk that the CPUPID information
cannot be stored in the page flags.  This patch removes support for
automatic NUMA support on 32-bit x86.

Signed-off-by: Mel Gorman <[email protected]>
Cc: David Vrabel <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Anvin <[email protected]>
Cc: Fengguang Wu <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Steven Noonan <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: Mel Gorman

arch/x86/Kconfig

@@ -26,7 +26,7 @@ config X86
 	select ARCH_MIGHT_HAVE_PC_SERIO
 	select HAVE_AOUT if X86_32
 	select HAVE_UNSTABLE_SCHED_CLOCK
-	select ARCH_SUPPORTS_NUMA_BALANCING
+	select ARCH_SUPPORTS_NUMA_BALANCING if X86_64
 	select ARCH_SUPPORTS_INT128 if X86_64
 	select ARCH_WANTS_PROT_NUMA_PROT_NONE
 	select HAVE_IDE