On Fri, May 19, 2017 at 09:07:31AM +1000, Nicholas Piggin wrote: > On Thu, 18 May 2017 12:30:28 -0400 > Don Zickus <dzickus@xxxxxxxxxx> wrote: > > > (adding Uli) > > > > On Fri, May 19, 2017 at 01:50:26AM +1000, Nicholas Piggin wrote: > > > I'd like to make it easier for architectures that have their own NMI / > > > hard lockup detector to reuse various configuration interfaces that are > > > provided by generic detectors (cmdline, sysctl, suspend/resume calls). > > > > > > I'd also like to remove the dependency of arch hard lockup detectors > > > on the softlockup detector. The reason being these watchdogs can be > > > very small (sparc's is like a page of core code that does not use any > > > big subsystem like kthreads or timers). > > > > > > So I do this by adding a separate CONFIG_SOFTLOCKUP_DETECTOR, and > > > juggling around what goes under config options. HAVE_NMI_WATCHDOG > > > continues to be the config for arch to override the hard lockup > > > detector, which is expanded to cover a few more cases. > > > > Basically you are trying to remove the heavy HARDLOCKUP pieces to minimize > > the SOFTLOCKUP piece and use your own NMI detector, right? > > > > I am guessing you would then disable SOFTLOCKUP to remove all the kthread > > and timer stuff but continue to use the generic infrastructure to help > > manager your own NMI detector? > > Yes that's right. > > > A lot of the code is just re-organizing things and adding an explicit > > ifdef on SOFTLOCKUP, which seems fine to me. > > > > I just need to spend some time on some of your #else clauses to see what > > functionality is dropped when you use your approach. > > Okay, appreciated. I can trim down cc lists and send you my powerpc > WIP if you'd like to have a look. I am curious to know what IBM thinks there. Currently the HARDLOCKUP detector sits on top of perf. I get the impression, you are removing that dependency. Is that a permanent thing or are you thinking of switching back and forth depending on if SOFTLOCKUP is enabled or not? Cheers, Don
