Re: [Qemu-devel] [PATCH COLO-Frame v12 28/38] COLO: Process shutdown command for VM in COLO state

[Dr. David Alan Gilbert]

* zhanghailiang (address@hidden) 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 <address@hidden>
> Signed-off-by: zhanghailiang <address@hidden>
> Signed-off-by: Li Zhijian <address@hidden>
> ---
>  include/sysemu/sysemu.h |  3 +++
>  migration/colo.c        | 25 +++++++++++++++++++++++--
>  qapi-schema.json        |  4 +++-
>  vl.c                    | 26 ++++++++++++++++++++++++--
>  4 files changed, 53 insertions(+), 5 deletions(-)
> 
> 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 f4bb661..a094991 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -231,6 +231,7 @@ static int colo_do_checkpoint_transaction(MigrationState 
> *s,
>                                            QEMUSizedBuffer *buffer)
>  {
>      int ret;
> +    int colo_shutdown;
>      size_t size;
>      QEMUFile *trans = NULL;
>  
> @@ -258,6 +259,7 @@ static int colo_do_checkpoint_transaction(MigrationState 
> *s,
>          ret = -1;
>          goto out;
>      }
> +    colo_shutdown = colo_shutdown_requested;
>      vm_stop_force_state(RUN_STATE_COLO);
>      qemu_mutex_unlock_iothread();
>      trace_colo_vm_state_change("run", "stop");
> @@ -311,6 +313,15 @@ static int colo_do_checkpoint_transaction(MigrationState 
> *s,
>          goto out;
>      }
>  
> +    if (colo_shutdown) {
> +        colo_put_cmd(s->to_dst_file, COLO_COMMAND_GUEST_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();
> @@ -370,8 +381,9 @@ 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] 
> -
> @@ -442,6 +454,15 @@ static int colo_wait_handle_cmd(QEMUFile *f, int 
> *checkpoint_request)
>      case COLO_COMMAND_CHECKPOINT_REQUEST:
>          *checkpoint_request = 1;
>          return 0;
> +    case COLO_COMMAND_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 termiante the whole

Typo 'termiante'

> +        * process, do we need some cleanup?
> +        */
> +        qemu_thread_exit(0);

Yes, I'm not sure how much real cleanup you need during shutdown;
I wonder how a shutdown will look to the management layers above;
if they don't realise it's a shutdown they might try and do a failover
when one side exits.

>      default:
>          return -EINVAL;
>      }
> diff --git a/qapi-schema.json b/qapi-schema.json
> index f6ecb88..b5b1a02 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -754,12 +754,14 @@
>  #
>  # @vmstate-loaded: VM's state has been loaded by SVM.
>  #
> +# @guest-shutdown: shutdown require from PVM to SVM
> +#
>  # Since: 2.6
>  ##
>  { 'enum': 'COLOCommand',
>    'data': [ 'checkpoint-ready', 'checkpoint-request', 'checkpoint-reply',
>              'vmstate-send', 'vmstate-size','vmstate-received',
> -            'vmstate-loaded' ] }
> +            'vmstate-loaded', 'guest-shutdown' ] }
>  
>  ##
>  # @COLOMode
> diff --git a/vl.c b/vl.c
> index fca630b..1a61300 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1636,6 +1636,8 @@ 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;
> @@ -1767,6 +1769,10 @@ void qemu_system_guest_panicked(void)
>  void qemu_system_reset_request(void)
>  {
>      if (no_reboot) {
> +        qemu_system_shutdown_request();
> +        if (!shutdown_requested) {/* colo handle it ? */
> +            return;
> +        }
>          shutdown_requested = 1;

Do we still need that 'shutdown_requested = 1'  - it's already
true at this point or it returned?

>      } else {
>          reset_requested = 1;
> @@ -1840,14 +1846,30 @@ 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 in colo mode, we need do some significant work before respond to the
> +    * shutdown request.
> +    */
> +    if (migration_incoming_in_colo_state()) {
> +        return ; /* primary's responsibility */
> +    }
> +    if (migration_in_colo_state()) {
> +        colo_shutdown_requested = 1;
> +        return;
> +    }

Try to move most of this into migration/colo*.c ;
here you could just do:
    if (colo_shutdown()) {
        return;
    }

it's best to keep vl.c as simple as possible.

Dave

> +    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 / address@hidden / Manchester, UK