>= 2.6.9 kernels and kswapd using >50% CPU in games

[thomas_n]

I currently have a problem with kswapd0 suddenly eating >50% CPU when starting certain games with 2.6.9 or .10-rc1.
In 2.6.9 it went of after starting ut2004 and loading big (Onslaught) maps, now with .10-rc1 it starts doing this in savage ("Savage: The Battle for Newerth", not as hardware/RAM hungry as ut2004), UT2004 works fine again, nothing changed there patch or config wise.

Strange thing is that it also happens when I turn off swap, here are the two programs shown in top:


PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
35 root 25 0 0 0 0 R 64.8 0.0 2:13.65 kswapd0
13304 thomas 25 0 639m 192m 46m R 28.6 38.1 0:36.86 silverback.bin
(silverback.bin == savage binary)

Remarkable here is that the 639MB Virtual memory is more than my 512MB Ram, the 600 MB swap are not available (swapoff /dev/xy).

System is a Debian/Sid with selfcompiled kernel, PREEMT enabled. No other fancy stuff I can think of atm, everything is 100% stable in 2.6.8.1.

[thomas_n]

I did some more research (as if I hadn't google my fingertips off before :P) and it seems it's this issue seen with Doom3: http://zerowing.idsoftware.com/linux/doom/#head-0db57bd1dfd8826e672742bff9d1aba2d5ba6336

Strange, Doom3 ran fine under 2.6.9. Trying this patch http://ck.kolivas.org/patches/2.6/2.6.10/2.6.10-rc1/patches/vm-pages_scanned-active_list.patch now.

Edit: Yes, that little patch did it. Time they move that kind of b0rking to a 2.7 branch.

[darklegion]

2.6.9-cko3 also has this patch applied :)