out of memory,irq 154：nobody cared (try booting with the "irqpoll" option)

sorry for my english!
The system is centos5.4 and had cutted by somedoby,the system is run ok after two days,and give the message is "out of memory :killall ...mysql",that's not the most serious, "irq 154：nobody cared (try booting with the "irqpoll" option)" ,irq 154 is the eth3 irq number. what happened to my system?

Has your system been hacked? If so run rkhunter on it.

If not, please explain 'been cutted by somebody'