#!/usr/bin/perl
# Munin plugin for monitoring memory usage.
#
# FIELDS:
#		RAM Kernel	Kernel resident in RAM (and usually lobel swap_total\n";
#		RAM Locked	Locked memory pages from swap (Anon)
#		RAM Used	Anon, Exec + Libs, Page cache
#		RAM Avail	Free memory that can be immediately used
#
# Core logic developed by Brendan Gregg. 
# REFERENCE: http://www.brendangregg.com/k9toolkit.html - the swap diagram.
#
# COPYRIGHT: Copyright (c) 2004 Brendan Gregg.
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License
#  as published by the Free Software Foundation; either version 2
#  of the License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software Foundation,
#  Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
#  (http://www.gnu.org/copyleft/gpl.html)

# Perldoc

=pod

=head1 NAME

raminfo - Plugin for monitoring memory usage

=head1 AUTHOR

Christian Braum, chrisi_braum@web.de
 
Core logic developed by Brendan Gregg. See K9Toolkit:
http://www.brendangregg.com/K9Toolkit/swapinfo

=head1 LICENSE

GPL 2.

=cut

# Main
use strict;
use warnings;

if( defined $ARGV[0] )
{
	if( $ARGV[0] eq "config" )
	{
		&config();
	}
	else
	{
		&output();
	}
}
else
{
	&output();
}


sub value # get value for variables
{
	my %h_ramvalues;
	use Sun::Solaris::Kstat;
	my $Kstat = Sun::Solaris::Kstat->new();

	# --- Fetch Hardware info ---
	### pagesize
	$ENV{PATH} = "/usr/bin";
	chomp(my $PAGESIZE = `pagesize`);
	my $PAGETOMB = $PAGESIZE / (1024 * 1024);
	my $PAGETOKB = $PAGESIZE / (1024);
	my $PAGETOBYTE = $PAGESIZE;
	my $BLOCKTOP = 512 / $PAGESIZE;

	### RAM total
	my $ram_total = 0;
	foreach my $i (keys(%{$Kstat->{lgrp}})) {                          # instance
       		foreach my $c (keys(%{$Kstat->{lgrp}->{$i}})) {            # class
                	$ram_total += $Kstat->{lgrp}->{$i}->{$c}->{"pages installed"};
        	}
	}

	### RAM available for the OS
	my $pagestotal = $Kstat->{unix}->{0}->{system_pages}->{pagestotal};


	# --- Fetch VM info ---
	my %VMnow;
	my %VMinfo;
	my %VMold;

	foreach my $count (0..12) 
	{
		#
		#  The values are counters that increment each second, here we
		#  check them several times and look for the value changing.
		#  (reading them once then again a second later was not reliable).
		#

		foreach my $var ( "freemem" ) 
		{
			$VMnow{$var} = $Kstat->{unix}->{0}->{vminfo}->{$var};
			unless ($count) {
				$VMold{$var} = $VMnow{$var};
				next;
			}
			if (($VMnow{$var} != $VMold{$var}) && (! $VMinfo{$var})) {
				$VMinfo{$var} = $VMnow{$var} - $VMold{$var};
			}
		}
		select(undef, undef, undef, 0.1);
		$Kstat->update();
	}

	my $freemem = $Kstat->{unix}->{0}->{system_pages}->{freemem};
	my $pageslocked = $Kstat->{unix}->{0}->{system_pages}->{pageslocked};
	my $pp_kernel = $Kstat->{unix}->{0}->{system_pages}->{pp_kernel};

	### ---RAM Calculations ---
	my $ram_unusable = $ram_total - $pagestotal;
	my $ram_kernel;
	my $ram_locked;

	if ($pp_kernel < $pageslocked) {
		# here we assume all pp_kernel pages are in memory,
		$ram_kernel = $pp_kernel;
		$ram_locked = $pageslocked - $pp_kernel;
	} else {
		# here we assume pageslocked is entirerly kernel,
		$ram_kernel = $pageslocked;
		$ram_locked = 0;
	}

	my $ram_used = $pagestotal - $freemem - $ram_kernel - $ram_locked;

	### format values
	
	my $freemem_B      = sprintf( "%d ", $freemem * $PAGETOBYTE );
	my $pp_kernel_B    = sprintf( "%d ", $pp_kernel * $PAGETOBYTE );
	my $pageslocked_B  = sprintf( "%d ", $pageslocked * $PAGETOBYTE );
	my $pagestotal_B   = sprintf( "%d ", $pagestotal * $PAGETOBYTE );
	my $ram_unusable_B = sprintf( "%d ", $ram_unusable * $PAGETOBYTE );
	my $ram_kernel_B   = sprintf( "%d ", $ram_kernel * $PAGETOBYTE ); 
	my $ram_locked_B   = sprintf( "%d ", $ram_locked * $PAGETOBYTE );
	my $ram_used_B     = sprintf( "%d ", $ram_used * $PAGETOBYTE );
	my $ram_total_B    = sprintf( "%d ", $ram_total * $PAGETOBYTE );

	# --- assign the variables  ---	
	$h_ramvalues{"Unusable.value"} = "$ram_unusable_B";
	$h_ramvalues{"Kernel.value"} = "$ram_kernel_B";
	$h_ramvalues{"Locked.value"} = "$ram_locked_B";
	$h_ramvalues{"Used.value"} = "$ram_used_B";
	$h_ramvalues{"Avail.value"} = "$freemem_B";
	$h_ramvalues{"Total.value"} = "$ram_total_B";

	return %h_ramvalues;
}  # sub value

sub output       # print out the values of the variables.
{
	my %h_ramvalue=value();

	print "Unusable.value " . $h_ramvalue{"Unusable.value"} . "\n";
	print "Kernel.value " . $h_ramvalue{"Kernel.value"} . "\n";
	print "Locked.value " . $h_ramvalue{"Locked.value"} . "\n";
	print "Used.value " . $h_ramvalue{"Used.value"} . "\n";
	print "Avail.value " . $h_ramvalue{"Avail.value"} . "\n";
}

sub config       # print config message and exit.
{
	    my %h_ramvalue=value();

	    print "graph_args --base 1024 -l 0 --upper-limit " .  $h_ramvalue{"Total.value"}. "--rigid"  . "\n";
	    print "graph_vlabel Bytes\n";
	    print "graph_title RAM usage\n";
	    print "graph_category system\n";
	    print "graph_info This graph shows what the machine uses RAM for.\n";
	    print "graph_order ";

	    #print "vmalloc_used " if exists $mems{'VmallocUsed'};


	    print "Unusable ",
	      "Kernel ",
		"Locked ",
		  "Used ",
		    "Avail ",
		    "\n";
	  
	    print "Unusable.label Unusable \n";
	    print "Unusable.draw AREA \n";
	    print "Unusable.info RAM consumed by the OBP and TSBs.\n";
	    print "Kernel.label Kernel \n";
	    print "Kernel.draw STACK \n";
	    print "Kernel.info Kernel resident in RAM.\n";
	    print "Locked.label Locked \n";
	    print "Locked.draw STACK \n";
	    print "Locked.info Locked memory pages from swap.\n";
	    print "Used.label Used\n";
	    print "Used.draw STACK\n";
	    print "Used.info RAM used.\n";
	    print "Avail.label Avail\n";
	    print "Avail.draw STACK\n";
	    print "Avail.info Free RAM.\n";
} # sub config