On Fri, Jun 08, 2012 at 12:52:54PM +0200, Juan Quintela wrote:
> Isaku Yamahata <yamahata@xxxxxxxxxxxxx> wrote:
> > This patch prepares for postcopy livemigration.
> > It introduces -postcopy option and its internal flag, migration_postcopy.
> > It introduces -postcopy-flags for chaging the behavior of incoming postcopy
> > mainly for benchmark/debug.
>
> Why do we need postcopy flag? -incoming should be enough to detect that
> we are doing postcopy.
>
> QLIST_HEAD(, LoadStateEntry) loadvm_handlers =
> QLIST_HEAD_INITIALIZER(loadvm_handlers);
> LoadStateEntry *le, *new_le;
> uint8_t section_type;
> unsigned int v;
> int ret;
>
> if (qemu_savevm_state_blocked(NULL)) {
> return -EINVAL;
> }
>
> v = qemu_get_be32(f);
> if (v != QEMU_VM_FILE_MAGIC)
> return -EINVAL;
>
> v = qemu_get_be32(f);
> if (v == QEMU_VM_FILE_VERSION_COMPAT) {
> fprintf(stderr, "SaveVM v2 format is obsolete and don't work anymore\n");
> return -ENOTSUP;
> }
> if (v != QEMU_VM_FILE_VERSION)
> return -ENOTSUP;
>
> Shouldn't we be able to change some version field here and make the
> "recognition of postcopy automatic"? Having to hack around a new
> command line option for each page is not going to be nice. And about
> postcopy flags, if they are for "incoming side", please consider just
> sent that flags on the stream as a first field?
Yes, you are right.
If bumping version is allowed, -postcopy can be dropped with auto detection.
-postcopy-flags can be dropped because it is used only for benchmark purpose
to change incoming side behavior independent of outgoing side.
--
yamahata
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