Originally Posted by DeiF
Just this morning I noticed that my system was being sluggish (a while after resuming from suspend IIRC), so I opened up "top" to see what was happening.
I saw Xorg using 1400MB of virtual memory, 1300MB of "res" (and a little less shared, I think ~1200MB). That, coupled with other programs (e.g. Firefox) was triggering swap usage, since I only have 2GB of RAM.
So I launched xrestop to see what was the program storing so much pixmaps into Xorg. To my surprise the most demanding app was "plasma-desktop" eating only 50MB, and the rest being much much less.
After a quick googling, I then found the pmap command, so I did "pmap -d xorgpid" and found 2 lines near the top to be the most consuming. One was marked as [heap] and the other [anon].
I stopped there, as I didn't know how to further investigate this.
If I'm able to reproduce this I'll comment further.
How many pixmaps did xrestop say plasma-desktop was using? The total memory size number reported by xrestop is not always accurate. It would be interesting the next time this happens to try killing plasma-desktop (and other applications, one by one) to see if any one of them causes the X server to free that memory.
There are resources other than pixmaps that could be taking up that memory too.