On Fri, May 26, 2017 at 10:39:09AM +1000, Nicholas Piggin wrote: > On Thu, 25 May 2017 10:08:33 -0400 > Don Zickus <dzickus@xxxxxxxxxx> wrote: > > > On Thu, May 25, 2017 at 06:28:56PM +1000, Nicholas Piggin wrote: > > > After reconfiguring watchdog sysctls etc., architecture specific > > > watchdogs may not get all their parameters updated. > > > > > > watchdog_reconfigure() can be implemented to pull the new values > > > in and set the arch NMI watchdog. > > > > I understand the reason for this patch and I don't have any real objection > > on how it was implemented within the constraints of all the current logic. > > > > I just wonder if the current logic should be adjusted to make the hardlockup > > detector, namely the perf implementation more separate so it can handle what > > you would like more cleanly. > > > > The watchdog_nmi_reconfigure is sort of hackish, but it is hard to fault you > > based on how things are designed. I am going to poke at it a little bit, > > but I will probably not find time to do much and accept what you have for > > now. > > I actually agree with you. These patches are basically an initial bridge > to get us to decoupling hld-perf from hld-arch, but the code could > definitely use several more passes to clean things up. Makes sense. :-) > > One thing we want to be mindful of is some watchdogs are very light weight, > minimal, and some may not even want to call C code (at least from the NMI Agreed. > and touch-watchdog paths). But having said that, it may not be a bad idea > to have implementations provide a watchdog driver struct with some of the > methods and reconfiguration they support. E.g., suspend/resume, stop/start > on CPUs, adjust timeouts, etc.). Hehe. I was hoping to avoid doing that, but it may lead there over time. > > I didn't want to go the whole hog and over-engineer something that doesn't > work though, so I'm hoping we can get the powerpc watchdog in, and then > keep working on the apis. Agreed. > > Let me know what you think after you poke at it though. I will. Cheers, Don
