On Wed, Feb 25, 2015 at 04:51:34PM +0000, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" > > 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 CMD_PING handler > > Signed-off-by: Dr. David Alan Gilbert > --- > include/migration/migration.h | 17 ++++++++++++++++ > migration/migration.c | 45 +++++++++++++++++++++++++++++++++++++++++++ > 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 c514dd4..6775747 100644 > --- a/include/migration/migration.h > +++ b/include/migration/migration.h > @@ -41,6 +41,13 @@ struct MigrationParams { > bool shared; > }; > > +/* Commands sent on the return path from destination to source*/ > +enum mig_rpcomm_cmd { "command" doesn't seem like quite the right description for these rp messages. > + MIG_RP_CMD_INVALID = 0, /* Must be 0 */ > + MIG_RP_CMD_SHUT, /* sibling will not send any more RP messages */ > + MIG_RP_CMD_PONG, /* Response to a PING; data (seq: be32 ) */ > +}; > + > typedef struct MigrationState MigrationState; > > /* State for the incoming migration */ > @@ -48,6 +55,7 @@ struct MigrationIncomingState { > QEMUFile *file; > > QEMUFile *return_path; > + QemuMutex rp_mutex; /* We send replies from multiple threads */ > }; > > MigrationIncomingState *migration_incoming_get_current(void); > @@ -169,6 +177,15 @@ int64_t migrate_xbzrle_cache_size(void); > > int64_t xbzrle_cache_resize(int64_t new_size); > > +/* Sending on the return path - generic and then for each message type */ > +void migrate_send_rp_message(MigrationIncomingState *mis, > + enum mig_rpcomm_cmd cmd, > + uint16_t len, uint8_t *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 a36ea65..80d234c 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -78,6 +78,7 @@ MigrationIncomingState *migration_incoming_state_new(QEMUFile* f) > { > mis_current = g_malloc0(sizeof(MigrationIncomingState)); > mis_current->file = f; > + qemu_mutex_init(&mis_current->rp_mutex); > > return mis_current; > } > @@ -88,6 +89,50 @@ void migration_incoming_state_destroy(void) > mis_current = NULL; > } > > +/* > + * Send a message on the return channel back to the source > + * of the migration. > + */ > +void migrate_send_rp_message(MigrationIncomingState *mis, > + enum mig_rpcomm_cmd cmd, > + uint16_t len, uint8_t *data) Using (void *) for data would avoid casts in a bunch of the callers. > +{ > + trace_migrate_send_rp_message((int)cmd, len); > + qemu_mutex_lock(&mis->rp_mutex); > + qemu_put_be16(mis->return_path, (unsigned int)cmd); > + qemu_put_be16(mis->return_path, len); > + qemu_put_buffer(mis->return_path, data, len); > + 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. None-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_CMD_SHUT, 4, (uint8_t *)&buf); ^ sizeof(buf) would be safer > +} > + > +/* > + * 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_CMD_PONG, 4, (uint8_t *)&buf); It occurs to me that you could define PONG as returning the whole buffer that PING sends, instead of just 4-bytes. Might allow for some more testing of variable sized messages. > +} > + > void qemu_start_incoming_migration(const char *uri, Error **errp) > { > const char *p; > diff --git a/savevm.c b/savevm.c > index d082738..7084d07 100644 > --- a/savevm.c > +++ b/savevm.c > @@ -1008,7 +1008,7 @@ 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 99e00b5..4f3eff8 100644 > --- a/trace-events > +++ b/trace-events > @@ -1379,6 +1379,7 @@ 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 cmd, uint16_t len) "cmd=%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 -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson