Re: [libvirt] [PATCH 08/24] qemu: Use -incoming defer for migrations

On Thu, Nov 12, 2015 at 19:37:10 +0100, Jiri Denemark wrote: > Traditionally, we pass incoming migration URI on QEMU command line, > which has some drawbacks. Depending on the URI QEMU may initialize its > migration state immediately without giving us a chance to set any > additional migration parameters (this applies mainly for fd: URIs). For > some URIs the monitor may be completely blocked from the beginning until > migration is finished, which means we may be stuck in qmp_capabilities > command without being able to send any QMP commands. > > QEMU solved this by introducing "defer" parameter for -incoming command > line option. This will tell QEMU to prepare for an incoming migration > while the actual incoming URI is sent using migrate-incoming QMP > command. Before calling this command we can normally talk to the > monitor and even set any migration parameters which will be honored by > the incoming migration. > > Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; > --- > src/qemu/qemu_capabilities.c | 3 +++ > src/qemu/qemu_capabilities.h | 3 +++ > src/qemu/qemu_migration.c | 36 ++++++++++++++++++++++++++++ > src/qemu/qemu_migration.h | 5 ++++ > src/qemu/qemu_process.c | 12 ++++++++++ > src/qemu/qemu_process.h | 1 + > tests/qemucapabilitiesdata/caps_2.4.0-1.caps | 1 + > 7 files changed, 61 insertions(+) > [...] > diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c > index 4d5b966..0c4c94a 100644 > --- a/src/qemu/qemu_migration.c > +++ b/src/qemu/qemu_migration.c > @@ -2951,6 +2951,42 @@ qemuMigrationIncomingURI(const char *migrateFrom, > } > > > +int > +qemuMigrationRunIncoming(virQEMUDriverPtr driver, > + virDomainObjPtr vm, > + const char *uri, > + qemuDomainAsyncJob asyncJob) Is there a reason why this doesn't take the new fancy struct containing all the data and doing the decisions internally ...

> @@ -4929,6 +4936,11 @@ int qemuProcessStart(virConnectPtr conn, > if (qemuProcessUpdateVideoRamSize(driver, vm, asyncJob) < 0) > goto error; > > + if (incoming && > + incoming->deferredURI && ... rather than having to check here ... > + qemuMigrationRunIncoming(driver, vm, incoming->deferredURI, asyncJob) < 0) And extract the params?