Re: [PATCH 1/3] migration/colo: wrap incoming checkpoint process into new helper

[Dr. David Alan Gilbert]

* Hailiang Zhang (address@hidden) wrote:
> Split checkpoint incoming process into a helper.
> 
> Signed-off-by: Hailiang Zhang <address@hidden>

Reviewed-by: Dr. David Alan Gilbert <address@hidden>

> ---
>  migration/colo.c | 260 ++++++++++++++++++++++++-----------------------
>  1 file changed, 133 insertions(+), 127 deletions(-)
> 
> diff --git a/migration/colo.c b/migration/colo.c
> index 2c88aa57a2..93c5a452fb 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -664,13 +664,138 @@ void migrate_start_colo_process(MigrationState *s)
>      qemu_mutex_lock_iothread();
>  }
>  
> -static void colo_wait_handle_message(QEMUFile *f, int *checkpoint_request,
> -                                     Error **errp)
> +static void colo_incoming_process_checkpoint(MigrationIncomingState *mis,
> +                      QEMUFile *fb, QIOChannelBuffer *bioc, Error **errp)
> +{
> +    uint64_t total_size;
> +    uint64_t value;
> +    Error *local_err = NULL;
> +    int ret;
> +
> +    qemu_mutex_lock_iothread();
> +    vm_stop_force_state(RUN_STATE_COLO);
> +    trace_colo_vm_state_change("run", "stop");
> +    qemu_mutex_unlock_iothread();
> +
> +    /* FIXME: This is unnecessary for periodic checkpoint mode */
> +    colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_REPLY,
> +                 &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
> +
> +    colo_receive_check_message(mis->from_src_file,
> +                       COLO_MESSAGE_VMSTATE_SEND, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
> +
> +    qemu_mutex_lock_iothread();
> +    cpu_synchronize_all_pre_loadvm();
> +    ret = qemu_loadvm_state_main(mis->from_src_file, mis);
> +    qemu_mutex_unlock_iothread();
> +
> +    if (ret < 0) {
> +        error_setg(errp, "Load VM's live state (ram) error");
> +        return;
> +    }
> +
> +    value = colo_receive_message_value(mis->from_src_file,
> +                             COLO_MESSAGE_VMSTATE_SIZE, &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
> +
> +    /*
> +     * Read VM device state data into channel buffer,
> +     * It's better to re-use the memory allocated.
> +     * Here we need to handle the channel buffer directly.
> +     */
> +    if (value > bioc->capacity) {
> +        bioc->capacity = value;
> +        bioc->data = g_realloc(bioc->data, bioc->capacity);
> +    }
> +    total_size = qemu_get_buffer(mis->from_src_file, bioc->data, value);
> +    if (total_size != value) {
> +        error_setg(errp, "Got %" PRIu64 " VMState data, less than expected"
> +                    " %" PRIu64, total_size, value);
> +        return;
> +    }
> +    bioc->usage = total_size;
> +    qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL);
> +
> +    colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_RECEIVED,
> +                 &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        return;
> +    }
> +
> +    qemu_mutex_lock_iothread();
> +    vmstate_loading = true;
> +    ret = qemu_load_device_state(fb);
> +    if (ret < 0) {
> +        error_setg(errp, "COLO: load device state failed");
> +        qemu_mutex_unlock_iothread();
> +        return;
> +    }
> +
> +#ifdef CONFIG_REPLICATION
> +    replication_get_error_all(&local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        qemu_mutex_unlock_iothread();
> +        return;
> +    }
> +
> +    /* discard colo disk buffer */
> +    replication_do_checkpoint_all(&local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        qemu_mutex_unlock_iothread();
> +        return;
> +    }
> +#else
> +    abort();
> +#endif
> +    /* Notify all filters of all NIC to do checkpoint */
> +    colo_notify_filters_event(COLO_EVENT_CHECKPOINT, &local_err);
> +
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        qemu_mutex_unlock_iothread();
> +        return;
> +    }
> +
> +    vmstate_loading = false;
> +    vm_start();
> +    trace_colo_vm_state_change("stop", "run");
> +    qemu_mutex_unlock_iothread();
> +
> +    if (failover_get_state() == FAILOVER_STATUS_RELAUNCH) {
> +        failover_set_state(FAILOVER_STATUS_RELAUNCH,
> +                        FAILOVER_STATUS_NONE);
> +        failover_request_active(NULL);
> +        return;
> +    }
> +
> +    colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED,
> +                 &local_err);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +    }
> +}
> +
> +static void colo_wait_handle_message(MigrationIncomingState *mis,
> +                QEMUFile *fb, QIOChannelBuffer *bioc, Error **errp)
>  {
>      COLOMessage msg;
>      Error *local_err = NULL;
>  
> -    msg = colo_receive_message(f, &local_err);
> +    msg = colo_receive_message(mis->from_src_file, &local_err);
>      if (local_err) {
>          error_propagate(errp, local_err);
>          return;
> @@ -678,10 +803,9 @@ static void colo_wait_handle_message(QEMUFile *f, int 
> *checkpoint_request,
>  
>      switch (msg) {
>      case COLO_MESSAGE_CHECKPOINT_REQUEST:
> -        *checkpoint_request = 1;
> +        colo_incoming_process_checkpoint(mis, fb, bioc, errp);
>          break;
>      default:
> -        *checkpoint_request = 0;
>          error_setg(errp, "Got unknown COLO message: %d", msg);
>          break;
>      }
> @@ -692,10 +816,7 @@ void *colo_process_incoming_thread(void *opaque)
>      MigrationIncomingState *mis = opaque;
>      QEMUFile *fb = NULL;
>      QIOChannelBuffer *bioc = NULL; /* Cache incoming device state */
> -    uint64_t total_size;
> -    uint64_t value;
>      Error *local_err = NULL;
> -    int ret;
>  
>      rcu_register_thread();
>      qemu_sem_init(&mis->colo_incoming_sem, 0);
> @@ -749,134 +870,19 @@ void *colo_process_incoming_thread(void *opaque)
>      }
>  
>      while (mis->state == MIGRATION_STATUS_COLO) {
> -        int request = 0;
> -
> -        colo_wait_handle_message(mis->from_src_file, &request, &local_err);
> +        colo_wait_handle_message(mis, fb, bioc, &local_err);
>          if (local_err) {
> -            goto out;
> +            error_report_err(local_err);
> +            break;
>          }
> -        assert(request);
>          if (failover_get_state() != FAILOVER_STATUS_NONE) {
>              error_report("failover request");
> -            goto out;
> -        }
> -
> -        qemu_mutex_lock_iothread();
> -        vm_stop_force_state(RUN_STATE_COLO);
> -        trace_colo_vm_state_change("run", "stop");
> -        qemu_mutex_unlock_iothread();
> -
> -        /* FIXME: This is unnecessary for periodic checkpoint mode */
> -        colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_REPLY,
> -                     &local_err);
> -        if (local_err) {
> -            goto out;
> -        }
> -
> -        colo_receive_check_message(mis->from_src_file,
> -                           COLO_MESSAGE_VMSTATE_SEND, &local_err);
> -        if (local_err) {
> -            goto out;
> -        }
> -
> -        qemu_mutex_lock_iothread();
> -        cpu_synchronize_all_pre_loadvm();
> -        ret = qemu_loadvm_state_main(mis->from_src_file, mis);
> -        qemu_mutex_unlock_iothread();
> -
> -        if (ret < 0) {
> -            error_report("Load VM's live state (ram) error");
> -            goto out;
> -        }
> -
> -        value = colo_receive_message_value(mis->from_src_file,
> -                                 COLO_MESSAGE_VMSTATE_SIZE, &local_err);
> -        if (local_err) {
> -            goto out;
> -        }
> -
> -        /*
> -         * Read VM device state data into channel buffer,
> -         * It's better to re-use the memory allocated.
> -         * Here we need to handle the channel buffer directly.
> -         */
> -        if (value > bioc->capacity) {
> -            bioc->capacity = value;
> -            bioc->data = g_realloc(bioc->data, bioc->capacity);
> -        }
> -        total_size = qemu_get_buffer(mis->from_src_file, bioc->data, value);
> -        if (total_size != value) {
> -            error_report("Got %" PRIu64 " VMState data, less than expected"
> -                        " %" PRIu64, total_size, value);
> -            goto out;
> -        }
> -        bioc->usage = total_size;
> -        qio_channel_io_seek(QIO_CHANNEL(bioc), 0, 0, NULL);
> -
> -        colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_RECEIVED,
> -                     &local_err);
> -        if (local_err) {
> -            goto out;
> -        }
> -
> -        qemu_mutex_lock_iothread();
> -        vmstate_loading = true;
> -        ret = qemu_load_device_state(fb);
> -        if (ret < 0) {
> -            error_report("COLO: load device state failed");
> -            qemu_mutex_unlock_iothread();
> -            goto out;
> -        }
> -
> -#ifdef CONFIG_REPLICATION
> -        replication_get_error_all(&local_err);
> -        if (local_err) {
> -            qemu_mutex_unlock_iothread();
> -            goto out;
> -        }
> -
> -        /* discard colo disk buffer */
> -        replication_do_checkpoint_all(&local_err);
> -        if (local_err) {
> -            qemu_mutex_unlock_iothread();
> -            goto out;
> -        }
> -#else
> -        abort();
> -#endif
> -        /* Notify all filters of all NIC to do checkpoint */
> -        colo_notify_filters_event(COLO_EVENT_CHECKPOINT, &local_err);
> -
> -        if (local_err) {
> -            qemu_mutex_unlock_iothread();
> -            goto out;
> -        }
> -
> -        vmstate_loading = false;
> -        vm_start();
> -        trace_colo_vm_state_change("stop", "run");
> -        qemu_mutex_unlock_iothread();
> -
> -        if (failover_get_state() == FAILOVER_STATUS_RELAUNCH) {
> -            failover_set_state(FAILOVER_STATUS_RELAUNCH,
> -                            FAILOVER_STATUS_NONE);
> -            failover_request_active(NULL);
> -            goto out;
> -        }
> -
> -        colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED,
> -                     &local_err);
> -        if (local_err) {
> -            goto out;
> +            break;
>          }
>      }
>  
>  out:
>      vmstate_loading = false;
> -    /* Throw the unreported error message after exited from loop */
> -    if (local_err) {
> -        error_report_err(local_err);
> -    }
>  
>      /*
>       * There are only two reasons we can get here, some error happened
> -- 
> 2.21.0
> 
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK