Hello Vivek, On Tue, 2011-08-02 at 15:21 -0400, Vivek Goyal wrote: > > We have added the panic notifier in the past in order to be able to > > configure the action that should be done in case of panic using our > > shutdown actions infrastructure. We can configure the action using sysfs > > and we are able to configure that a stand-alone dump should be started > > as action for panic. > > > > Now with the two stage dump approach we would like to keep the > > possibility to trigger a stand-alone dump even if kdump is installed. > > The stand-alone dumper will be started in case of a kernel panic and > > then the procedure we discussed will happen: Jump into kdump and if > > program check occurs do stand-alone dump as backup. > > Frankly speaking this jumping to stand alone kernel by default is not > making any sense to me. Once you have already determined from /sys that > in case of crash a user has set the action to kdump, then we should > simply call crash_kexec() If the user has set the panic action to kdump, we jump directly to crash_kexec(). This then works like on all other architectures. Only if the user has specified panic action stand-alone dump, we do the detour via the stand-alone dump tools. > like other architectures and jump to stand > alone kernel only if some piece of code is corrupted and that action > failed. > > What's the point of jumping to stand alone kenrel in case of panic() > and then re-enter it back to original kernel using crash_kexec(). Sound > like a very odd design choice to me. > > I am now I am repeating this question umpteen time simply because > I never got a good answer except "we have to do it this way". Sometimes communication is really hard and frustrating. ... but at least we are still communicating. Ok very last try: * We can use the same mechanism for manual dump and automatic dump on panic: IPL the stand-alone dump tools. kdump check and backup stand-alone dump is implemented only in the stand-alone dump code. If we would do it like you suggested, we would have to do it twice - in the kernel and in the stand-alone dump tools: - kernel: Try kdump and if kdump fails trigger standalone dump tool - Stand-alone dump tool: Try kdump and if kdump fails do full dump * Still the panic action is configured via sysfs as the user is already used to on s390. * It fits much better into our whole s390 infrastructure. Believe me, we have discussed that here a long time. I think you do not have a full overview here. Perhaps you just have to believe that. Michael
