On Sat, 22 Jan 2022 18:55:14 +0800 Baoquan He <bhe@xxxxxxxxxx> wrote: > On 01/21/22 at 05:31pm, Guilherme G. Piccoli wrote: > ...... > > > IMHO, the right solution is to split the callbacks into 2 or more > > > notifier list. Then we might rework panic() to do: > > > > > > void panic(void) > > > { > > > [...] > > > > > > /* stop watchdogs + extra info */ > > > atomic_notifier_call_chain(&panic_disable_watchdogs_notifier_list, 0, buf); > > > atomic_notifier_call_chain(&panic_info_notifier_list, 0, buf); > > > panic_print_sys_info(); > > > > > > /* crash_kexec + kmsg_dump in configurable order */ > > > if (!_crash_kexec_post_kmsg_dump) { > > > __crash_kexec(NULL); > > > smp_send_stop(); > > > } else { > > > crash_smp_send_stop(); > > > } > > > > > > kmsg_dump(); > > > if (_crash_kexec_post_kmsg_dump) > > > __crash_kexec(NULL); > > > > > > /* infinite loop or reboot */ > > > atomic_notifier_call_chain(&panic_hypervisor_notifier_list, 0, buf); > > > atomic_notifier_call_chain(&panic_rest_notifier_list, 0, buf); > > > > > > console_flush_on_panic(CONSOLE_FLUSH_PENDING); > > > [...] > > > Two notifier lists might be enough in the above scenario. I would call > > > them: > > > > > > panic_pre_dump_notifier_list > > > panic_post_dump_notifier_list > > > > > > > > > It is a real solution that will help everyone. It is more complicated now > > > but it will makes things much easier in the long term. And it might be done > > > step by step: > > > > > > 1. introduce the two notifier lists > > > 2. convert all users: one by one > > > 3. remove the original notifier list when there is no user > > > > That's a great idea! I'm into it, if we have a consensus. The thing that > > scares me most here is that this is a big change and consumes time to > > implement - I'd not risk such time if somebody is really against that. > > So, let's see more opinions, maybe the kdump maintainers have good input. > > I am fine with it. As long as thing is made clear, glad to see code is > refactored to be more understandable and improved. Earlier, during several > rounds of discussion between you and Petr, seveal pitfalls have been > pointed out and avoided. > > Meanwhile, I would suggest Masa and HATAYAMA to help give input about > panic_notifier usage and refactory. AFAIK, they contributed code and use > panic_notifier in their product or environment a lot, that will be very > helpful to get the first hand information from them. > > Hi Masa, HATAYANA, > > Any comment on this? (Please ignore this if it's not in your care.) No, that looks good idea to me. BTW, the 'dump' in the new notifieers means both kmsg_dump and crash dump, right? Thank you, -- Masami Hiramatsu <mhiramat@xxxxxxxxxx> _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec