From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: [PATCH 2/6] xen/hvm kexec: unregister shutdown+sysrq watches during reboot Date: Thu, 28 Jul 2011 13:02:19 +0200 Message-ID: <20110728110219.GA22307@aepfle.de> References: <4E30A9BC0200007800073B1F@nat28.tlf.novell.com> <20110728052500.GA13940@aepfle.de> <1311850379.24408.119.camel@cthulhu.hellion.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <1311850379.24408.119.camel@cthulhu.hellion.org.uk> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ian Campbell Cc: "xen-devel@lists.xensource.com" , Jan Beulich List-Id: xen-devel@lists.xenproject.org On Thu, Jul 28, Ian Campbell wrote: > Getting into the kdump kernel is a kexec like operation though and > shares many of the code paths, doesn't it? The big difference is that kdump is entered in an unreliable state, while kexec is a controlled reboot. > > > If this requires changes outside the kernel (e.g. state reset helpers > > > in hypervisor or tools) - so be it. > > > > Are you suggesting that there have to be ways for a domU to query the > > state of its registered watches and shut them all down during very early > > boot? > > Perhaps the xenstore protocol could be enhanced with a mechanism to > clear all existing watches? A kernel could call that at start of day. I wonder why xenstore knows that sysrq and shutdown nodes are busy, while the device, backend and state files can be watched twice. Olaf