On Mon, Jun 15, 2009 at 03:33:41PM -0500, Anthony Liguori wrote: > The basic issue is that: > > migrate_fd_put_ready(): bdrv_flush_all(); > > Does: > > block.c: > > foreach block driver: > drv->flush(bs); > > Which in the case of raw, is just fsync(s->fd). > > Any submitted request is not queued or flushed which will lead to the > request being dropped after the live migration. you mean any request submitted _after_ that is not queued, right? > > Is anyone working on fixing this? Does anyone have a clever idea how to > fix this without just waiting for all IO requests to complete? If I understood you correctly, we could do something in the lines of dirty tracking for I/O devices. use register_savevm_live() instead of register_savevm() for those, and keep doing passes until we reach stage 3, for some criteria. We can then just flush the remaining requests on that device and mark[1] it somewhere. We can then either stop that device, so that new requests never arrive, or stop the VM entirely. [1] By mark, I mean the verb "to mark", not our dear friend Mark McLaughing. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
