The writer-director of “In Bruges,” the playwright-turned-filmmaker Martin McDonagh, sells out and makes his first Hollywood film, “Seven Psychopaths,” a commentary on selling out. Well, that and Hollywood’s obsession with psychopaths. And his own.

True to title, it’s about seven psychopaths and a screenwriter named Martin writing a movie about them.

But as a possibly psychopathic character tells the writer (Colin Farrell), “You’re the one so fascinated by psychopaths. After a while they get tiresome, don’t you think?”

Like generations of great talents “going Hollywood” before him, McDonagh takes his shot at having it both ways.

He hired a quartet of the coolest character actors in the business and revels in the presence of Farrell, Chrisopher Walken, Woody Harrelson and Sam Rockwell.

He imitates and takes a blood-stained swipe at genre nerds such as Quentin Tarantino and Joe Carnahan and their movie lover’s style of bloody-minded movie.

He has characters comment on situations and scenarios as they “rewrite” scenes, endings and shootouts for the screenplay Martin is sure will be a box office hit.

And McDonagh makes Linda Ronstadt’s “Different Drum” the theme song of his writer-hero.

But don’t get me wrong, it’s not that I knock it, because “Psychopaths” is profane, gruesome and hysterically over the top. The sheer pleasure of watching Walken work with his disciples — Harrelson and Rockwell (maniacally mannered here) — and watching McDonagh’s alter ego, Farrell, in another McDonagh role worthy of his talents, is undeniable.

But after a while, even those pleasures wear thin.

Martin is blocked, at a loss for fleshing out his next script, which only has a title: “Seven Psychopaths.”

His antic actor pal, Billy (Rockwell) tries to help with tales of a Quaker stalker (Harry Dean Stanton), who follows the man who murdered his daughter into hell itself. A Buddhist (Vietnamese) psychopath? What would motivate him? And so on.

Billy and Hans (Walken) are running a little dognapping-for-reward-money scam so that Hans can care for his terminally ill wife. And they’ve nabbed the wrong dog, a Shih Tzu beloved by mobster Charlie (Harrelson), who is willing to kill to get that dog back.

There’s a serial killer stalking Los Angeles, well, L.A. bad guys.

He’s the Jack O’Diamonds killer, a masked avenger who shows up at opportune moments, shoots people and leaves playing cards on his victims.

And if that’s not enough to work with, Martin interviews a “real” psychopath (Tom Waites), a grizzled old man who misses the wife who led him on a cross-country murder spree years before.

Walken gives his pop-eyed glare and his patented colorful line-readings and eccentric pronunciations to every scene — “halucin-O-gens.”

Farrell wears a pretentious swoopy L.A. screenwriter haircut and acts hurt every time somebody criticizes his script in progress.

No, the onscreen Martin and off-camera Martin (McDonagh) can’t write a realistic female to save their lives. So Abbie Cornish, Gabourey Sidibe and Olga Kurylenko just have glorified cameos. They’re set decor, place-holders to give us a break between the next funny-violent tour de force/tour de profanity moment involving the leads.

But as long as you remember that this is just a “Smokin’ Aces” for the literary-minded, you’ll be fine.