Re: [Qemu-devel] [PATCH COLO-Frame v14 24/40] COLO: Process shutdown command for VM in COLO state

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* zhanghailiang (zhang.zhanghailiang@huawei.com) wrote:
> If VM is in COLO FT state, we should do some extra work before normal shutdown
> process. SVM will ignore the shutdown command if this command is issued directly
> to it, PVM will send the shutdown command to SVM if it gets this command.
> 
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

although one question below.

Dave

> ---
> v14:
> - Remove 'colo_shutdown' variable, use colo_shutdown_request directly
> v13:
> - Move COLO shutdown related codes to colo.c file (Dave's suggestion)
> ---
>  include/migration/colo.h |  2 ++
>  include/sysemu/sysemu.h  |  3 +++
>  migration/colo.c         | 42 ++++++++++++++++++++++++++++++++++++++++--
>  qapi-schema.json         |  4 +++-
>  stubs/migration-colo.c   |  5 +++++
>  vl.c                     | 19 ++++++++++++++++---
>  6 files changed, 69 insertions(+), 6 deletions(-)
> 
> diff --git a/include/migration/colo.h b/include/migration/colo.h
> index e32eef4..919b135 100644
> --- a/include/migration/colo.h
> +++ b/include/migration/colo.h
> @@ -35,4 +35,6 @@ COLOMode get_colo_mode(void);
>  
>  /* failover */
>  void colo_do_failover(MigrationState *s);
> +
> +bool colo_shutdown(void);
>  #endif
> diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> index 3bb8897..91eeda3 100644
> --- a/include/sysemu/sysemu.h
> +++ b/include/sysemu/sysemu.h
> @@ -52,6 +52,8 @@ typedef enum WakeupReason {
>      QEMU_WAKEUP_REASON_OTHER,
>  } WakeupReason;
>  
> +extern int colo_shutdown_requested;
> +
>  void qemu_system_reset_request(void);
>  void qemu_system_suspend_request(void);
>  void qemu_register_suspend_notifier(Notifier *notifier);
> @@ -59,6 +61,7 @@ void qemu_system_wakeup_request(WakeupReason reason);
>  void qemu_system_wakeup_enable(WakeupReason reason, bool enabled);
>  void qemu_register_wakeup_notifier(Notifier *notifier);
>  void qemu_system_shutdown_request(void);
> +void qemu_system_shutdown_request_core(void);
>  void qemu_system_powerdown_request(void);
>  void qemu_register_powerdown_notifier(Notifier *notifier);
>  void qemu_system_debug_request(void);
> diff --git a/migration/colo.c b/migration/colo.c
> index 515d561..92be985 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -330,6 +330,18 @@ static int colo_do_checkpoint_transaction(MigrationState *s,
>          goto out;
>      }
>  
> +    if (colo_shutdown_requested) {
> +        colo_put_cmd(s->to_dst_file, COLO_MESSAGE_GUEST_SHUTDOWN, &local_err);
> +        if (local_err) {
> +            goto out;
> +        }

I wonder what actually happens in this case? Does it eventually shutdown?

> +        qemu_fflush(s->to_dst_file);
> +        colo_shutdown_requested = 0;
> +        qemu_system_shutdown_request_core();
> +        /* Fix me: Just let the colo thread exit ? */
> +        qemu_thread_exit(0);
> +    }
> +
>      ret = 0;
>      /* Resume primary guest */
>      qemu_mutex_lock_iothread();
> @@ -390,8 +402,9 @@ static void colo_process_checkpoint(MigrationState *s)
>          }
>  
>          current_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> -        if (current_time - checkpoint_time <
> -            s->parameters[MIGRATION_PARAMETER_X_CHECKPOINT_DELAY]) {
> +        if ((current_time - checkpoint_time <
> +            s->parameters[MIGRATION_PARAMETER_X_CHECKPOINT_DELAY]) &&
> +            !colo_shutdown_requested) {
>              int64_t delay_ms;
>  
>              delay_ms = s->parameters[MIGRATION_PARAMETER_X_CHECKPOINT_DELAY] -
> @@ -465,6 +478,15 @@ static void colo_wait_handle_cmd(QEMUFile *f, int *checkpoint_request,
>      case COLO_MESSAGE_CHECKPOINT_REQUEST:
>          *checkpoint_request = 1;
>          break;
> +    case COLO_MESSAGE_GUEST_SHUTDOWN:
> +        qemu_mutex_lock_iothread();
> +        vm_stop_force_state(RUN_STATE_COLO);
> +        qemu_system_shutdown_request_core();
> +        qemu_mutex_unlock_iothread();
> +        /* the main thread will exit and terminate the whole
> +        * process, do we need some cleanup?
> +        */
> +        qemu_thread_exit(0);
>      default:
>          *checkpoint_request = 0;
>          error_setg(errp, "Got unknown COLO command: %d", cmd);
> @@ -636,3 +658,19 @@ out:
>  
>      return NULL;
>  }
> +
> +bool colo_shutdown(void)
> +{
> +    /*
> +    * if in colo mode, we need do some significant work before respond
> +    * to the shutdown request.
> +    */
> +    if (migration_incoming_in_colo_state()) {
> +        return true; /* primary's responsibility */
> +    }
> +    if (migration_in_colo_state()) {
> +        colo_shutdown_requested = 1;
> +        return true;
> +    }
> +    return false;
> +}
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 7fec696..4d8ba04 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -752,12 +752,14 @@
>  #
>  # @vmstate-loaded: VM's state has been loaded by SVM.
>  #
> +# @guest-shutdown: shutdown require from PVM to SVM
> +#
>  # Since: 2.6
>  ##
>  { 'enum': 'COLOMessage',
>    'data': [ 'checkpoint-ready', 'checkpoint-request', 'checkpoint-reply',
>              'vmstate-send', 'vmstate-size', 'vmstate-received',
> -            'vmstate-loaded' ] }
> +            'vmstate-loaded', 'guest-shutdown' ] }
>  
>  ##
>  # @COLOMode
> diff --git a/stubs/migration-colo.c b/stubs/migration-colo.c
> index a6cd6e5..1996cd9 100644
> --- a/stubs/migration-colo.c
> +++ b/stubs/migration-colo.c
> @@ -43,3 +43,8 @@ void qmp_x_colo_lost_heartbeat(Error **errp)
>                       " with --enable-colo option in order to support"
>                       " COLO feature");
>  }
> +
> +bool colo_shutdown(void)
> +{
> +    return false;
> +}
> diff --git a/vl.c b/vl.c
> index f16fe2d..90da8d1 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1631,6 +1631,8 @@ static NotifierList wakeup_notifiers =
>      NOTIFIER_LIST_INITIALIZER(wakeup_notifiers);
>  static uint32_t wakeup_reason_mask = ~(1 << QEMU_WAKEUP_REASON_NONE);
>  
> +int colo_shutdown_requested;
> +
>  int qemu_shutdown_requested_get(void)
>  {
>      return shutdown_requested;
> @@ -1762,7 +1764,10 @@ void qemu_system_guest_panicked(void)
>  void qemu_system_reset_request(void)
>  {
>      if (no_reboot) {
> -        shutdown_requested = 1;
> +        qemu_system_shutdown_request();
> +        if (!shutdown_requested) {/* colo handle it ? */
> +            return;
> +        }
>      } else {
>          reset_requested = 1;
>      }
> @@ -1835,14 +1840,22 @@ void qemu_system_killed(int signal, pid_t pid)
>      qemu_notify_event();
>  }
>  
> -void qemu_system_shutdown_request(void)
> +void qemu_system_shutdown_request_core(void)
>  {
> -    trace_qemu_system_shutdown_request();
>      replay_shutdown_request();
>      shutdown_requested = 1;
>      qemu_notify_event();
>  }
>  
> +void qemu_system_shutdown_request(void)
> +{
> +    trace_qemu_system_shutdown_request();
> +    if (colo_shutdown()) {
> +        return;
> +    }
> +    qemu_system_shutdown_request_core();
> +}
> +
>  static void qemu_system_powerdown(void)
>  {
>      qapi_event_send_powerdown(&error_abort);
> -- 
> 1.8.3.1
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK