CONFIG_WEAK_ORDERING is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

CONFIG_WEAK_ORDERING (not configurable)

configname: CONFIG_WEAK_ORDERING

Linux/MIPS Kernel Configuration
└─>CPU selection
└─>WEAK_ORDERING
In linux kernel since version 2.6.20 (release Date: 2007-02-04)