Free Up Cache Memory in Ubuntu

출처 : http://goo.gl/oexhJ

Ever wondered how to remove the cache memory in Ubuntu? Linux kernels 2.6.16 and newer provide a mechanism to clear the inode, page, and dentry caches on demand. All you have to do is echo a value to the proc filesystem, and you’re done. Follow the recipe below:

As this is a non-destructive operation and dirty objects are not freeable, run:
sync

To free pagecache:
sudo sh -c "echo 1 > /proc/sys/vm/drop_caches"

To free dentries and inodes:
sudo sh -c "echo 2 > /proc/sys/vm/drop_caches"

To free pagecache, dentries and inodes:
sudo sh -c "echo 3 > /proc/sys/vm/drop_caches"

Hope this works for you all.