Linux kernel 2.6.16 and newer provide a way to clear the inode, page, and dentry caches on the Linux system. Writing to this will cause the kernel to drop clean caches, dentries and inodes from memory, causing that memory to become free. Login as root and run the following commands.
• Clear pagecache:
sync; echo 1 > /proc/sys/vm/drop_caches
• Clear dentries and inodes:
sync; echo 2 > /proc/sys/vm/drop_caches
• Clear pagecache, dentries and inodes:
sync; echo 3 > /proc/sys/vm/drop_caches
