Re: X11 server lock-up and garbage on the screen

[Riccardo Mottola <riccardo.mottola%libero.it@localhost>]

Hi,

On 04/10/12 11:00, Michael van Elst wrote:
> riccardo.mottola%libero.it@localhost (Riccardo Mottola) writes:
>
> > 2) the "freeze" is only local. I cannot switch consoles, no keyboard
> > response, but telnet connection remain active and I can even restart X11
> > and it will work.
> The freeze is only in the display, neither X nor wscons can restore
> a sane display mode. There is a small chance that vbetool from pkgsrc
> can do that.
But I think it shouldn't happen in the first place. I may accept that an 
application gets killed if it uses too much reosurces, but this should 
end more gracefully. But read below.

> > UVM: pid 907 (LaternaMagica), uid 1000 killed: out of swap
> That's what kills your application.
>
> Like other OOM-killers, ours need to take a guess on which process
> to kill. Apparently it prefers the application instead of the X server.
So perhaps while running under a debugger, the behaviour becomes different.
In dmesg I read only "killed: out of swap" for my applications, not once 
for the X server instead. If it gets killed for OOM, I should get a 
message for it.

> Your X server probably needs memory as well, and both, application and 
> X are together too large. There may be also side-effects from using 
> shared memory transport or maybe DRI (DRI is only for the local display). 
yes, something additional perhaps comes into play. I don't get a killed 
message for the X server and the memory usage appears to be indeed quite 
big. I shall check on other machines which do not crash when visualizing 
the same image, which memory consumption I do get in about the same 
condition.
> > When run on an exported display, the top says for LaternaMagica:
> >    322 multix    85    0    68M   56M select     0:06  0.00%  0.00%
> > LaternaMagic
> The interesting part is: how large is the X server before it crashes.
I was able to see this in top:

 1692 multix    85    0   586M  309M select     0:02  2.44%  2.44% Xorg

This time the application was killed. X continued to work. But on exit, 
I got garbage again on the screen.

I don't appear to have a big swap indeed:
Memory: 121M Act, 5212K Inact, 4K Wired, 39M Exec, 20M File, 319M Free
Swap: 129M Total, 9976K Used, 119M Free

I wonder if I can increase it to 256MB gracefully? How?

Riccardo