CONFIG_PPC_MM_SLICES is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

CONFIG_PPC_MM_SLICES (not configurable)

modulename: slice.ko

configname: CONFIG_PPC_MM_SLICES

Linux Kernel Configuration
└─>Processor support
└─>PPC_MM_SLICES
In linux kernel since version 2.6.23 (release Date: 2007-10-09)  
source code:
arch/powerpc/mm/slice.c
is selected by
CONFIG_SPU_FS_64K_LS