My stab at finding memory used by processes

This perl script just goes through /proc/maps, finding inodes numbered with 0 and adds those sizes. Seems to over-report things with our servers, probably because it counts all pages even if they're copy on write, don't know how to get around that.

Any comments are welcome.

#!/usr/bin/perl -w
use strict;
use File::Glob ':glob';

my $procregex = qr /^(\S+)-(\S+) \S+ \S+ \S+ (\S+)/;

sub process_mapsfile {
    my ($path) = @_;

    open(MAPSFD, $path);

    my $totalsize = 0;
    while(<MAPSFD>)
    {
	if (!/$procregex/)
	{
	    #print "Couldn't match\n$_\n";
	    next;
	}
	else
	{
	    #print "Matched\n$_\n";
	}

	#print "line = $_";
	my $start = int(hex($1));
	my $end = int(hex($2));
	my $inode = int($3);
	#print "inode = $inode, end = $end, start = $start\n";
	if($inode == 0)
	{
	    my $size = $end - $start;
	    $totalsize += $size;
	}
    }

    close(MAPSFD);
    return $totalsize;
}

my $totalsize = 0;
my @files = </proc/*>;
foreach my $file (@files)

{
    # if we have a pid file, parse maps file
    if($file =~ /\/proc\/\d+/)
    {
	$totalsize += process_mapsfile($file . "/maps");
    }
}

print "size = $totalsize\n";