kstats are data structures maintained by various kernel subsystems and drivers. They provide
a mechanism for exporting data from the kernel to user programs without requiring
that the program read kernel memory or have superuser privilege. For more information,
see kstat(1M) or kstat(3KSTAT).
Note - kstat data structures with system_pages name in the unix module do not report
statistics for cachefree. cachefree is not supported, starting in the Solaris 9 release.