====== Filesystem Cache ======
Linux does extensively use free memory to cache filesystem pages.

===== Drop Caches =====
Since linux-2.6.16 there is a mechanism to explicitly drop the filesystem
cache. This can be achieved simply by echoing a number to the file
///proc/sys/vm/drop_caches//. Valid numbers are:
^ Number ^ Effect ^
| 1 | drop page cache |
| 2 | drop dentries and inodes |
| 3 | combination of 1 and 2 |