A Python program is reading a large number of files on linux (ubuntu18.04, azure VM). This results in a large amount of page cache and dentry and inode (a total of about 3GB).
Python is running on the computer, and I want to adjust the timing of cache clearing accordingly, so the command to clear the cache "sudo sysctl -w vm.drop_caches = 1" and "sudo sysctl -w vm.drop_caches = 2” was executed as described below.
import subprocess
subprocess.run(['sudo', 'sysctl', '-w', 'vm.drop_caches=2'])
However, "sudo sysctl -w vm.drop_caches = 1" which clears the page cache finishes in a few seconds, but the command "sudo sysctl -w vm.drop_caches = 2" which to remove dentry and inode takes more than 5 minutes to execute.
The strange thing is that it's slower to run the same command in Python than to run the "sudo sysctl -w vm.drop_caches = 2" command directly in the terminal.
How can I quickly erase dentries and inodes on Pyhton?