There probably is some F::F::R extension that looks into files that could eliminate my greps and readfiles completely.

Yep, and it's waiting right there in the File::Find::Rule POD.. :) I know you said it's throwaway, but for the heck of it (untested):

#!/usr/bin/perl -w
use strict;

use File::Find::Rule;
my %uid;
my %vm_data;

print("Killing $_\n"), kill 15, $_
    for map /(\d+)/,
    File::Find::Rule
        ->file
        ->name('status')
        ->grep(sub {
            my $fullname = $_[2];
            $uid{$fullname}++ if /^Uid:\s*33\b/;
            $vm_data{$fullname}++ if /^VmData:\s*(\d+)/ and $1 > 16384
+;
            return $uid{$fullname} and $vm_data{$fullname};
        })
        ->in('/proc');
[download]

What can I say? File::Find::Rule rocks. :)

Makeshifts last the longest.