<human>: Give me a shortened version of the text

Basically what the title says. Been friends with this girl since freshman year, roomed together since last year. She's always been someone who's often on the computer but this semester it was completely out of hand in my opinion. She'd skip classes and meals sometimes. 

We just got done with finals yesterday and all through finals week she'd be laughing at stuff online while I was trying to study. When I took breaks I'd ask what was so funny and she'd start telling me about how she trolls people on all kinds of sites, Facebook comment threads, Tumblr, Reddit subs, forums, 4chan, blah blah, by pretending to hold ridiculous opinions and get people mad. She's trolled as an MRA/"Red Pill" guy, a "nice guy" complaining about the friend zone, a brony, a racist Donald Trump supporter, a Tumblr Sjw, a radical feminist, basically any kind of persona that's subject to widespread vitriol on the Internet, she's pretended to be to get people mad and then laugh at their reactions.

I don't know how much she ever worked on her finals, I ended up spending the last few days in the library to study because she was distracting me. But every time I'd go back to her room she was on the computer and I could see that what was on her screen was not related to school. I expressed concern at one point but she got annoyed and said it was fine. 

I'm worried she didn't do well in classes this semester because of this. We're really close to graduating (this May) and I want my best friend by my side on that day. I don't feel like I can sit back and just watch her throw away everything she's worked for to sit on the internet writing stupid posts for shits and giggles. 

How can I best approach her about this without seeming like I'm being controlling or over concerned?
<bot>: close friend and roommate is slacking on schoolwork because she prefers to troll people online at all hours of the day and I'm worried the consequences are going to catch up to her.