Vivek Goyal wrote: > On Thu, Oct 18, 2007 at 12:06:51AM -0700, Andrew Morton wrote: >> On Thu, 18 Oct 2007 15:45:08 +0900 Takenori Nagano <t-nagano at ah.jp.nec.com> wrote: >> I can sort-of see what this is doing. Runtime-definable management of >> which notifier functions will be called on a panic? Or maybe I >> misunderstood. >> >> But even if I did understand, I don't understand why Linux needs this >> feature - what are the use cases, what is the value to our users? >> >> Can you please flesh that information out a bit more? >> > > Hi Andrew, > > Takenori wants to make kdb and kdump co-exist. Currently after panic() > panic_notifier_list is not executed if kdump is configured. Before list > is executed, system will boot into second kernel to capture the dump. Hence > if even if kdb was registered on panic_notifier_list, it will never get > a chance to run. Yes, it is true. But I don't mind only kdb and kdump co-exist. Keith Owen said, > > My stance is that _all_ the RAS tools (kdb, kgdb, nlkd, netdump, lkcd, > > crash, kdump etc.) should be using a common interface that safely puts > > the entire system in a stopped state and saves the state of each cpu. > > Then each tool can do what it likes, instead of every RAS tool doing > > its own thing and they all conflict with each other, which is why this > > thread started. > > > > It is not the kernel's job to decide which RAS tool runs first, second > > etc., it is the user's decision to set that policy. Different sites > > will want different orders, some will say "go straight to kdump", other > > sites will want to invoke a debugger first. Sites must be able to > > define that policy, but we hard code the policy into the kernel. I agreed with him and I made new notifier function that users can change the order. Priority value in notifier blocks are hardcoded. If users want to change list order, they have to rebuild kernel. I think it is very unhappy. This is our discussion. http://www.gossamer-threads.com/lists/linux/kernel/797220?do=post_view_threaded#797220 In addition, we can use new notifier function to reboot_notifier, die_chain if users want to use. >> The patches are somewhat wordwrapped - please check your email client >> configuration, thanks. Sorry, I'll resend. Thanks, Takenori
