CONFIG_4KSTACKS is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k

Use 4Kb for kernel stacks instead of 8Kb

configname: CONFIG_4KSTACKS

Linux Kernel Configuration
└─>Use 4Kb for kernel stacks instead of 8Kb
In linux kernel since version 2.6.12  
If you say Y here the kernel will use a 4Kb stacksize for the
kernel stack attached to each process/thread. This facilitates
running more threads on a system and also reduces the pressure
on the VM subsystem for higher order allocations.