From mboxrd@z Thu Jan 1 00:00:00 1970 From: Horms Subject: Re: [Patch] Enable "sysrq c" handler for domU coredump Date: Tue, 1 Aug 2006 18:26:23 +0900 Message-ID: <20060801092622.GA28388@verge.net.au> References: <20060801064805.GA14886@verge.net.au> <50C6B549C9FCF3takebe_akio@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <50C6B549C9FCF3takebe_akio@jp.fujitsu.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Akio Takebe Cc: Muli Ben-Yehuda , xen-devel , Kouya Shimura List-Id: xen-devel@lists.xenproject.org On Tue, Aug 01, 2006 at 06:06:35PM +0900, Akio Takebe wrote: > >On Tue, Aug 01, 2006 at 01:39:23PM +0900, Akio Takebe wrote: > >> Hi, Horms > >> > >> > > >> >That seems fine to me. Though there was some resistance to a > >> >patch I sent which adds a panic option to xen-console, which > >> >is the hypervisor equivalent of sysrq. > >> > > >> This patch focus only manually dumping domU's core. > >> How can I use the panic option of xen-console? > >> I thought your patch to panic xen. > >> Can I dump domU's core with the option? > > > >Sorry, I was not clear. > > > >Yes, my patch is to panic (or more recently cause a crash dump) > >in the hypervisor. It does not give any special behaviour to > >the domains. > > > >What I meant was, that the idea of adding a panic to domU's sysrq > >is similar to my idea of adding panic to the xen console. And I was > >asked to change this patch to make it trigger a kdump directly, > >rather than a panic. > > > >I think that your sysrq patch and my xen-console panic patches > >are related, and I wanted to bring that into the discussion. > > > Horms, what you said, that I had better call crash_kexec() > than panic() on dom0? Thats not what I was thinking, but now you mention it... > If so, I agree for dom0 directly calling crash_kexec(). > But because now vmlinux is used as both dom0 and domU, > we cannot use ifdef for separateing dom0 and domU. > So I call panic() on both dom0 and domU. > I also think option like a unknown_nmi_panic is useful > and necessary for dump and debug. > > Everyone, how about the below? > 1. If crash_kexec() is called on dom0, dom0 do hypercall > then xen do kexec/kdump > 2. If crash_kexec() is called on domU, domU do hypercall > then xen do panic_domain(), and domU's core is dumped. I think that is a good idea, because it gives consistent behaviour for dom0 and domU, even though the mechanics differ. Though if kexec for domU is merged, things may change at that time. > So I don't need to modify linux code. :-) :-) > Or How about "xm dump"? > (Probably I use panic_domain() by hypercall. > This way can probably dump HVM domain.) That is also a good idea, though it could be done as well, rather than instead of your crash_kexec() -> hypercall idea. > I think we need to have the way manually to dump domU, or Xen. > (Because for the time when domU or Xen don't panic > and spinloop and so on) That is a good point, which makes your xm dump idea somewhat more attactive than the crash_kexec() -> hypercall idea. But I still think they both make sense. -- Horms H: http://www.vergenet.net/~horms/ W: http://www.valinux.co.jp/en/