From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Helsley Subject: Re: cryo and mm->arg_start Date: Fri, 11 Jul 2008 15:01:13 -0700 Message-ID: <1215813673.5456.284.camel@localhost.localdomain> References: <20080711131345.GA18870@us.ibm.com> <1215794310.9139.6.camel@nimitz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1215794310.9139.6.camel@nimitz> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Dave Hansen Cc: Linux Containers List-Id: containers.vger.kernel.org On Fri, 2008-07-11 at 09:38 -0700, Dave Hansen wrote: > On Fri, 2008-07-11 at 08:13 -0500, Serge E. Hallyn wrote: > > > > One thing we could do here is to start extending the cryo approach > > with Eric's checkpoint-as-a-coredump (caac?). We generate the > > tiniest of coredumps which, at first, contains nothing but > > mm->arg_start and maybe a process id. It would be simplest if > > it also contained a filename for the real executable, > > The exec model sounds reasonable to me. > > But, I think the filename of the exe is going to have to be in the > checkpoint *already*. It is mapped by at least one of the VMAs, and > will probably be dumped as a normal file-backed area. Yes, the file that backed the exec will be there. Note that thanks to "stacking" filesystems the path to the file backing the exe is not _always_ going to be the same as the path to the file which userspace exec'd in the first place. You can see this by comparing the /proc//exe symlink with the file backing the VMA. This is important to any program which checks the /proc/self/exe symlink to find out where it's installed (Java does this, for example). I think it's possible to do this with a binfmt -- it's just one more detail to remember. Cheers, -Matt