Stock Android always using 100% physical memory. How to free it up with ADB?

I have a non-rooted phone. I just realized why Android is bad at memory management. I'm monitoring running progress in ADB shell with top. I can see the memory is about 100% used. Image resized. Click for full-size How do I stop unnecessary processes with ADB shell? Also, I can't scroll down top command. It shows weird char ^[[b. I think that's because the shell uses sh instead of bash. Any idea how to free up memory with ADB? Maybe pkill or what.