How do we make sure RAM will be made use of as big/much size as possible for caching, etc process for optimization when compiliing C/C++?
though ccache is basically installed on Linux, no definitive way to set it up to work the best,
there's about 7-11 GB ready idle exra Ram.. thanks before.
First have swap space defined. Read
man mkswap swapon
.Second, don't worry about it. Linux uses unallocated RAM for buffering and caching I/O, and will flush the caches and buffers (and free their RAM) when processes, like your compilation, want memory. Letting RAM just sit there, unused, while it could be used to speed up the system, is unwise.