So, in recent kernels since 2.6.31-rc1, there is a seemingly benign problem whose apparently manifestation is page allocation failures of GFP_ATOMIC allocations. The system recovers but there are large stalls even though on server systems, everything goes faster overall. The problem is particularly pronounced when using certain wireless cards but manifests in harder-to-diagnose stalls on machines with low memory under stress. The development methodology means that kernels come out very quickly even though right now, I would really prefer if the world would slow down while my poor test machines try to catch up.
I think I have a solution to this but it take several hours each time to figure out if forward progress has been made or not.
The lesson learnt here? Panic makes for poor decisions. I sent one patch what looked great at the time but have found out in the last few hours that it really sucks. While figuring this out for sure, I have to wait looking at a screen to painfully slowly update. To help the waiting, I found some beer, it's the Irish thing to do. Wonder what the rest of ye do :/