Memory Leakage in Conky with Lua

Question

Hi there, I've been experiencing ongoing memory leakage using my Conky + Lua scripts. It tends to keep accumulating memory until I kill the process and restart it. Highest I've seen it go is 10% of my 4gb of RAM, so it does get to be substantial if unchecked.
I did google it, and it mentioned something about cairo_destroy(cr), so I inserted it at the end of functions randomly where it made sense (to my limited scripting skills) and where it didn't (just in case), but it didn't seem to make any difference.
Here is the lua script - it creates rings as % bars, I believe it was taken from somewhere on the arch forums months ago where it was also modified.
Ring Meters by londonali1010 (2009)
This script draws percentage meters as rings. It is fully customisable; all options are described in the script.
To call this script in Conky, use the following (assuming that you save this script to ~/scripts/rings.lua):
lua_load ~/scripts/rings-v1.2.1.lua
lua_draw_hook_pre ring_stats
-- Background settings
corner_r=20
main_bg_colour=0x060606
main_bg_alpha=0.4
-- Ring color settings
ring_background_color = 0x000000
ring_background_alpha = 0.6
ring_foreground_color = 0x909090
ring_foreground_alpha = 1
-- Rings settings
settings_table = {
name='cpu',
arg='cpu2',
max=100,
bg_colour=ring_background_color,
bg_alpha=ring_background_alpha,
fg_colour=ring_foreground_color,
fg_alpha=ring_foreground_alpha,
x=50, y=55,
radius=31,
thickness=3,
start_angle=-180,
end_angle=0
name='cpu',
arg='cpu1',
max=100,
bg_colour=ring_background_color,
bg_alpha=ring_background_alpha,
fg_colour=ring_foreground_color,
fg_alpha=ring_foreground_alpha,
x=50, y=55,
radius=35,
thickness=3,
start_angle=-180,
end_angle=0
name='memperc',
arg='',
max=100,
bg_colour=ring_background_color,
bg_alpha=ring_background_alpha,
fg_colour=ring_foreground_color,
fg_alpha=ring_foreground_alpha,
x=205, y=55,
radius=32,
thickness=10,
start_angle=-180,
end_angle=-0
require 'cairo'
local function rgb_to_r_g_b(colour,alpha)
return ((colour / 0x10000) % 0x100) / 255., ((colour / 0x100) % 0x100) / 255., (colour % 0x100) / 255., alpha
end
local function draw_ring(cr,t,pt)
local w,h=conky_window.width,conky_window.height
local xc,yc,ring_r,ring_w,sa,ea=pt['x'],pt['y'],pt['radius'],pt['thickness'],pt['start_angle'],pt['end_angle']
local bgc, bga, fgc, fga=pt['bg_colour'], pt['bg_alpha'], pt['fg_colour'], pt['fg_alpha']
local angle_0=sa*(2*math.pi/360)-math.pi/2
local angle_f=ea*(2*math.pi/360)-math.pi/2
local t_arc=t*(angle_f-angle_0)
-- Draw background ring
cairo_arc(cr,xc,yc,ring_r,angle_0,angle_f)
cairo_set_source_rgba(cr,rgb_to_r_g_b(bgc,bga))
cairo_set_line_width(cr,ring_w)
cairo_stroke(cr)
-- Draw indicator ring
cairo_arc(cr,xc,yc,ring_r,angle_0,angle_0+t_arc)
cairo_set_source_rgba(cr,rgb_to_r_g_b(fgc,fga))
cairo_stroke(cr)
end
local function conky_ring_stats()
local function setup_rings(cr,pt)
local str=''
local value=0
str=string.format('${%s %s}',pt['name'],pt['arg'])
str=conky_parse(str)
value=tonumber(str)
if value == nil then value = 0 end
pct=value/pt['max']
draw_ring(cr,pct,pt)
end
if conky_window==nil then return end
local cs=cairo_xlib_surface_create(conky_window.display,conky_window.drawable,conky_window.visual, conky_window.width,conky_window.height)
local cr=cairo_create(cs)
local updates=conky_parse('${updates}')
update_num=tonumber(updates)
if update_num>1 then
for i in pairs(settings_table) do
setup_rings(cr,settings_table[i])
end
end
cairo_destroy(cr)
end
--[[ This is a script made for draw a transaprent background for conky ]]
local function conky_draw_bg()
if conky_window==nil then return end
local w=conky_window.width
local h=conky_window.height
local cs=cairo_xlib_surface_create(conky_window.display, conky_window.drawable, conky_window.visual, w, h)
local cr=cairo_create(cs)
-- local thick=2
cairo_move_to(cr,corner_r,0)
cairo_line_to(cr,w-corner_r,0)
cairo_curve_to(cr,w,0,w,0,w,corner_r)
cairo_line_to(cr,w,h-corner_r)
cairo_curve_to(cr,w,h,w,h,w-corner_r,h)
cairo_line_to(cr,corner_r,h)
cairo_curve_to(cr,0,h,0,h,0,h-corner_r)
cairo_line_to(cr,0,corner_r)
cairo_curve_to(cr,0,0,0,0,corner_r,0)
cairo_close_path(cr)
cairo_set_source_rgba(cr,rgb_to_r_g_b(main_bg_colour,main_bg_alpha))
--cairo_set_line_width(cr,thick)
--cairo_stroke(cr)
cairo_fill(cr)
cairo_destroy(cr)
end
function conky_main()
conky_draw_bg()
conky_ring_stats()
cairo_destroy(cr)
end
And this is called into conky via:
background no
override_utf8_locale no
use_xft yes
xftfont Monospace:size=8
## orig font cure
text_buffer_size 2048
update_interval 1.0
total_run_times 0
own_window yes
own_window_transparent yes
own_window_type desktop
own_window_colour 191919
own_window_hints undecorated,below,sticky,skip_taskbar,skip_pager
double_buffer yes
minimum_size 600 90
maximum_width 320
draw_shades no
draw_outline no
draw_borders no
draw_graph_borders no
default_color 909090
default_shade_color fed053
default_outline_color 7f8f9f
alignment br
gap_x 30
gap_y 50
no_buffers yes
uppercase no
cpu_avg_samples 2
override_utf8_locale no
color1 fff
border_inner_margin 5
border_outer_margin 5
own_window_argb_visual no
own_window_argb_value 200
lua_load ~/.conky/rings.lua
lua_draw_hook_pre main
Left out the conky TEXT section unless anybody desperately needs to see that too.
If anybody can point me in the right direction with this silly thing, that would be appreciated. Thanks!
Last edited by ugugii (2011-11-16 17:42:00)

Answer 1

No I meant that the destroy functions should not be in conky_main at all. Why? Because you are using cr as an argument when you have no local cr defined. You are passing the undefined value (nil) to these destroy functions and they do nothing.
Like I said, I don't use conky or cairo but it is generally a good idea to destroy a resource you create. If you don't you will get memory leaks because "creating" is usually vague language that comes down to allocating memory and "destroy" deallocates memory.
This line from your own post creates a surface and stores it in the cs variable:
local cs=cairo_xlib_surface_create(conky_window.display,conky_window.drawable,conky_window.visual, conky_window.width,conky_window.height)
Yet you forget to deallocate the surface stored in cs. So add a line like this after each cairo_destroy(cr):
cairo_surface_destroy(cs)
I hope that helps.