Messages in this thread | | | Date | Thu, 21 Nov 2002 15:31:04 -0500 | From | Brian Gerst <> | Subject | Re: [RFC] hangcheck-timer module |
| |
Joel Becker wrote: > 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 >
There is already an NMI watchdog that is better than what you propose, because it will also catch cases where something gets stuck with interrupts disabled.
-- Brian Gerst
- 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/
| |