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

Collaborative memory management

modulename: cmm.ko

configname: CONFIG_CMM

Linux Kernel Configuration
└─>Collaborative memory management
In linux kernel since version 2.6.12  
Select this option, if you want to enable the kernel interface
to reduce the memory size of the system. This is accomplished
by allocating pages of memory and put them "on hold". This only
makes sense for a system running in an LPAR where the unused pages
will be reused for other LPARs. The interface allows firmware to
balance memory across many LPARs.