Michael Roth <mdr...@linux.vnet.ibm.com> wrote: > On Tue, Jul 24, 2012 at 08:36:29PM +0200, Juan Quintela wrote: >> From: Umesh Deshpande <udesh...@redhat.com> >> >> This will be used to detect if last_block might have become invalid >> across different calls to ram_save_live.
> > Was it a bug in the old code to not do this? In the unthreaded version > it looks like last_block could still become invalid between iterations if it > was removed in the meantime, so I'm trying to understand why it's needed > now. Old code assumed that we _never_ do hotplug/unplug of anything during migration (I am still not convinced that everything works if we plug some devices, but now at least memory works). > And why do we re-sort when this happens? The old implementation didn't > seem to place any guarantees on the block ordering beyond the initial > sorting by block->idstr. After that they were sent in MRU order. It is a "subtle" attempt to try to get the memory in order when we suspend to disk. So we could compare two files done while we were stopped. And no, I didn't liked when it was introduced. Later, Juan.
