On Wed, 2012-06-20 at 00:55 +0200, Juan Quintela wrote: > > This was going to be my question. > > If we can do something like: send hash register, and get a bitmap of > the > ones that get changed, we should be good. Perhaps we need something > "interesting" like removing old entries (no clue if they got just > overwritten, or how they are replaced), and we should be good.
Right, we can do an initial "snapshot" and have the kernel start tracking changes from there. On the final step, we can then request from the kernel a new snapshot with a dirty bitmap. Or we can be even simpler, just do two snapshots and have qemu diff them itself :-) I am confident I can come up with something as far as the kernel and qemu <-> kernel interface goes. I need to get my head around the details on how to implement that two stage save process in qemu though and the corresponding restore which will need to read both snapshots and apply the diff before shooting it back to the kernel. BTW. Does migration in pure qemu (full system emu) works similarily, ie, two stage ? If it does I can easily prototype everything there. Cheers, Ben.
