Re: Possible memory leak in XFree86

On Fri, 2004-01-16 at 06:20, Jonathan Fosburgh wrote:
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> I am cross-posting this to -current, since the problem is occuring in that 
> environment.
> 
> I first noticed this as far back as 5.0-RELEASE, but I had chalked it up to 
> being hardware-related, for reasons I shall get into shortly.  The problem 
> has persisted throught XFree86 4.3.x (and through the most current snapshot 
> available in the ports).  I am also running KDE 3.x (3.1.x and now 3.2 
> BETA2).  I am running -CURRENT (updated within the past couple of weeks) on a 
> Pentium III-600mHz with 383MB (from dmesg) RAM.  Originally, I had an nvidia 
> Riva TNT2 video card.  For a brief time I used the nvidia drivers, but those 
> were so unstable I never found out if this particular problem was 
> reproduceable with them. I now have an ATI Radeon 9200 and I see the same 
> things.  
> 
> What is happening is that the X server slowly allocates more memory until all 
> physical RAM and page space are allocated, and the pager starts killing off 
> processes, eventually killing the X server.  This seems to screw up syscons 
> as well, and  I wind up having to reboot to get my text consoles back.   
> Things have gotten slightly better of late, sometimes the memory is freed and 
> the XFree86 process might go from say 400+MB (according to top) down to a 
> little less then 200MB, which appears to be normal for the Radeon using DRI.  
> But this is not always the case.  When I come in in the mornings I either 
> find my system very low on page space, or if I am gone for a couple of days I 
> will generally find that X has been killed.  I run screensavers and have DPMS 
> set up to send the monitor to power-save mode. I have reduced my screensaver 
> to just blanking the screen, but still to no avail.  This morning, I came in 
> (after having been out yesterday) to find that X had been killed after 
> running out of page space.
> 
> Now, here is why I initially thought it was hardware related (that is, in the 
> nvidia driver for XFree86): at home I have a Pentium III-600 with about the 
> same amount of memory, running XFree86 4.3.x, KDE 3.1.x, screensavers, DPMS, 
> etc.  The differences are that at home I have an SiS ViRGE video card 
> (incidentally, PCI versus AGP for work), and I am tracking -STABLE there.  
> Only every once in awhile do I run out of page space at home, but my paging 
> space is undersized there, whereas at work it is set to the recommended size 
> from when I did the install, 753MB. 
> 
> Where I am at now is trying to figure out where the memory is going, and how 
> to prevent it. :) Can anyone help me diagnose this?

Every month or so I see someone saying they think XFree86  is leaking
memory.  Of course, with this release of XFree86 having been out for
about a year now, there are probably no major memory leaks, especially
with such a commonly used driver like ATI.

The X Server allocates memory on behalf of clients.  What you are
seeing, I'm willing to bet, is some application you run is leaking
pixmaps, so the X Server continues allocating memory for it until OOM
killer starts killing things off.  You could try, when the memory usage
is very large, killing your apps off one by one and seeing when the
memory usage in the server goes back down.

-- 
Eric Anholt                                eta_at_lclark.edu          
http://people.freebsd.org/~anholt/         anholt_at_FreeBSD.org