[SOLVED] How do I apply changes I made in a linux kernel source code?

How do I apply changes I made in a linux kernel source code?

I'm fairly new to operating systems and I'm working on linux 5.15.0.sp inside a VirtualBox environment. I wanted to see the characteristics of each file systems by adding printk() to the source codes to see what specific actions triggers the printk(). I added some lines in /fs/ext4/file.c and /fs/btrfs/file.c

I understand that I have to rebuild/recompile the linux kernel to apply the changes. My question is, do I have to do the whole process of make to apply the changes?

When I first installed the linux kernel, I did the following steps:

make -j4
make modules -j4
sudo make modules_install -j4
sudo make install

Do I just repeat this steps for each change I make or is there a better way?

Solution

Through the comments, it is required to do the building process again then do a reboot just to make sure the changes are applied correctly!