Messages in this thread | | | Date | Thu, 21 Nov 2002 12:17:11 -0800 | From | Joel Becker <> | Subject | [RFC] hangcheck-timer module |
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Folks, Attached is a module, hangcheck-timer. It is used to detect when the system goes out to lunch for a period of time, such as when a driver like qla2x00 udelays a bunch. The module sets a timer. When the timer goes off, it then uses the TSC (warning: portability needed) to determine how much real time has passed. On a normal system, the real elapsed time will be almost identical to the expected timer duration. However, if a device decided to udelay for 60 seconds (or some other circumstance), the module takes notice. If the margin of error passes a threshold, the machine is rebooted. The module is currently used in a cluster environment. After some time out to lunch, the rest of the cluster will have given up on a machine. If the machine suddenly comes back and assumes it is still "live", bad things can happen. We can also see use for this in a debugging sense, for kernel hangs as well as driver code. That's why I'm proposing it for general inclusion. Comments? Thoughts?
Joel
Building: The module should happily build against most 2.4 kernels. The usual module building compile line: gcc -I /scratch/jlbec/kernel/linux-2.4.20-rc2/include \ -DMODULE -D__KERNEL__ -DLINUX -c -o hangcheck-timer.o \ hangcheck-timer.c
Running: Load the module with insmod. There are two options. "hangcheck_tick=<seconds>" specifies the timer timeout, and "hangcheck_margin=<seconds" specifies the margin of error.
Joel
--
"Friends may come and go, but enemies accumulate." - Thomas Jones
Joel Becker Senior Member of Technical Staff Oracle Corporation E-mail: joel.becker@oracle.com Phone: (650) 506-8127 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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