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

[Hailiang Zhang <zhang.zhanghailiang@huawei.com>]

On 2016/2/12 23:09, Dr. David Alan Gilbert wrote:
> * 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.
>

Thanks!

> 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?
>

No, the qemu will not exit from the main loop,
it seems that, we should ignore the error here, and go on the shutdown process.
I will fix it in next version.

>> +        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
>
> .
>