* Juan Quintela (quint...@redhat.com) wrote:
> "Dr. David Alan Gilbert (git)" <dgilb...@redhat.com> wrote:
> > From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
> >
> > Add migrate_send_rp_message to send a message from destination to source
> > along the return path.
> > (It uses a mutex to let it be called from multiple threads)
> > Add migrate_send_rp_shut to send a 'shut' message to indicate
> > the destination is finished with the RP.
> > Add migrate_send_rp_ack to send a 'PONG' message in response to a PING
> > Use it in the MSG_RP_PING handler
> >
> > Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> > ---
> > include/migration/migration.h | 17 ++++++++++++++++
> > migration/migration.c | 45
> > +++++++++++++++++++++++++++++++++++++++++++
> > migration/savevm.c | 2 +-
> > trace-events | 1 +
> > 4 files changed, 64 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > index 65fe5db..36caab9 100644
> > --- a/include/migration/migration.h
> > +++ b/include/migration/migration.h
> > @@ -42,12 +42,20 @@ struct MigrationParams {
> > bool shared;
> > };
> >
> > +/* Messages sent on the return path from destination to source */
> > +enum mig_rp_message_type {
> > + MIG_RP_MSG_INVALID = 0, /* Must be 0 */
> > + MIG_RP_MSG_SHUT, /* sibling will not send any more RP messages
> > */
> > + MIG_RP_MSG_PONG, /* Response to a PING; data (seq: be32 ) */
> > +};
> > +
> > typedef QLIST_HEAD(, LoadStateEntry) LoadStateEntry_Head;
> > /* State for the incoming migration */
> > struct MigrationIncomingState {
> > QEMUFile *file;
> >
> > QEMUFile *return_path;
> > + QemuMutex rp_mutex; /* We send replies from multiple threads */
> >
> > /* See savevm.c */
> > LoadStateEntry_Head loadvm_handlers;
> > @@ -179,6 +187,15 @@ int migrate_compress_level(void);
> > int migrate_compress_threads(void);
> > int migrate_decompress_threads(void);
> >
> > +/* Sending on the return path - generic and then for each message type */
> > +void migrate_send_rp_message(MigrationIncomingState *mis,
> > + enum mig_rp_message_type message_type,
> > + uint16_t len, void *data);
> > +void migrate_send_rp_shut(MigrationIncomingState *mis,
> > + uint32_t value);
> > +void migrate_send_rp_pong(MigrationIncomingState *mis,
> > + uint32_t value);
> > +
> > void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
> > void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
> > void ram_control_load_hook(QEMUFile *f, uint64_t flags);
> > diff --git a/migration/migration.c b/migration/migration.c
> > index 295f15a..afb19a1 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -85,6 +85,7 @@ MigrationIncomingState
> > *migration_incoming_state_new(QEMUFile* f)
> > mis_current = g_malloc0(sizeof(MigrationIncomingState));
> > mis_current->file = f;
> > QLIST_INIT(&mis_current->loadvm_handlers);
> > + qemu_mutex_init(&mis_current->rp_mutex);
> >
> > return mis_current;
> > }
> > @@ -182,6 +183,50 @@ void process_incoming_migration(QEMUFile *f)
> > qemu_coroutine_enter(co, f);
> > }
> >
> > +/*
> > + * Send a message on the return channel back to the source
> > + * of the migration.
> > + */
> > +void migrate_send_rp_message(MigrationIncomingState *mis,
> > + enum mig_rp_message_type message_type,
> > + uint16_t len, void *data)
> > +{
> > + trace_migrate_send_rp_message((int)message_type, len);
> > + qemu_mutex_lock(&mis->rp_mutex);
> > + qemu_put_be16(mis->return_path, (unsigned int)message_type);
> > + qemu_put_be16(mis->return_path, len);
> if (len) {
>
> > + qemu_put_buffer(mis->return_path, data, len);
> }
>
>
> ?
>
> We check for zero sized command on control commands but not on
> responses?
Or should I remove the check in the control commands case?
qemu_put_buffer looks like it's safe for size == 0
Dave
>
> > + qemu_fflush(mis->return_path);
> > + qemu_mutex_unlock(&mis->rp_mutex);
> > +}
> > +
> > +/*
> > + * Send a 'SHUT' message on the return channel with the given value
> > + * to indicate that we've finished with the RP. Non-0 value indicates
> > + * error.
> > + */
> > +void migrate_send_rp_shut(MigrationIncomingState *mis,
> > + uint32_t value)
> > +{
> > + uint32_t buf;
> > +
> > + buf = cpu_to_be32(value);
> > + migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf);
> > +}
> > +
> > +/*
> > + * Send a 'PONG' message on the return channel with the given value
> > + * (normally in response to a 'PING')
> > + */
> > +void migrate_send_rp_pong(MigrationIncomingState *mis,
> > + uint32_t value)
> > +{
> > + uint32_t buf;
> > +
> > + buf = cpu_to_be32(value);
> > + migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
> > +}
> > +
> > /* amount of nanoseconds we are willing to wait for migration to be down.
> > * the choice of nanoseconds is because it is the maximum resolution that
> > * get_clock() can achieve. It is an internal measure. All user-visible
> > diff --git a/migration/savevm.c b/migration/savevm.c
> > index a995014..d424c2a 100644
> > --- a/migration/savevm.c
> > +++ b/migration/savevm.c
> > @@ -1071,7 +1071,7 @@ static int loadvm_process_command(QEMUFile *f)
> > tmp32);
> > return -1;
> > }
> > - /* migrate_send_rp_pong(mis, tmp32); TODO: gets added later */
> > + migrate_send_rp_pong(mis, tmp32);
> > break;
> >
> > default:
> > diff --git a/trace-events b/trace-events
> > index 5967fdf..5738e3f 100644
> > --- a/trace-events
> > +++ b/trace-events
> > @@ -1399,6 +1399,7 @@ migrate_fd_cleanup(void) ""
> > migrate_fd_error(void) ""
> > migrate_fd_cancel(void) ""
> > migrate_pending(uint64_t size, uint64_t max) "pending size %" PRIu64 " max
> > %" PRIu64
> > +migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
> > migrate_transferred(uint64_t tranferred, uint64_t time_spent, double
> > bandwidth, uint64_t size) "transferred %" PRIu64 " time_spent %" PRIu64 "
> > bandwidth %g max_size %" PRId64
> >
> > # migration/rdma.c
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
