On Wed, May 04, 2016 at 11:17:29AM -0500, Timur Tabi wrote: > Pratyush Anand wrote: > >Its unique to SBSA because you have very little timeout here. kexec-tools > >upstream does not have any mechanism to handle watchdog timeout. Lets say even > >if we implement a framework there, the best it can do is to ping the watchdog > >again. > > Ok, so it's more accurate to say that kexec has a minimum watchdog timeout > requirement. What happens if the system admin sets the timeout to 5 seconds > arbitrarily? The system will reset during kexec, no matter which hardware > is used. > > This still sounds like a band-aid to me. We're just assuming that we need a > timeout of at least 20 seconds to support kexec. Frankly, this still sounds > like a problem the kexec developers needs to acknowledge and deal with. > > Still I'm okay with a patch that extends the timeout by programming WCV, but > it has to be commented as a hack specifically to support kexec because the > timeout might be too short. Then Wim can decide whether he supports such > changes. > I don't even understand how kexec-tools is involved in the first place. kexec-tools sounds like user space, which should execute _after_ the kernel and its modules are loaded (assuming modules are loaded from initramfs). If kexec-tools can somehow ping the watchdog (presumably by writing into the HW directly), I don't understand why it doesn't simply load the watchdog driver instead and let the watchdog core handle the heartbeats. I am really missing something here. How can kexec-tools do anything before the kernel is loaded ? Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
