From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: thoughts on checkpointing /proc/mounts Date: Mon, 02 Mar 2009 10:48:39 -0800 Message-ID: <1236019719.26788.505.camel@nimitz> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: 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: containers Cc: Ingo Molnar , Nathan Lynch , Alexey Dobriyan , Christoph Hellwig List-Id: containers.vger.kernel.org Christoph's suggestion that we go add f_ops individually is a really good way to get people thinking about individual cases that we have to deal with. Can we checkpoint an *open* /proc/mounts? I don't think we want to. It could get really nasty really fast. But, what if the f_pos is 0? That makes it a lot easier. If the "may checkpoint" flag is per-container (as Alexey has said) and one-way (as Ingo has said), does a single 'cat /proc/mounts' 5 days ago keep a container from being checkpointed today? I just don't think the container-wide flag works if it is one way. I think making it per-process or per-resource (so it can be more easily tracked at fork()/clone()/exec()) is the only way to go. It makes it so simple since only the 'cat /proc/mounts' process becomes uncheckpointable. Once it exits, we are OK and can checkpoint again. That all seems right to me. -- Dave