Re: [Qemu-devel] [PATCH COLO-Frame v12 23/38] COLO: Implement failover work for Primary VM

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

On 2015/12/18 23:35, Dr. David Alan Gilbert wrote:
> * zhanghailiang (zhang.zhanghailiang@huawei.com) wrote:
>> For PVM, if there is failover request from users.
>> The colo thread will exit the loop while the failover BH does the
>> cleanup work and resumes VM.
>>
>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>> ---
>> v12:
>> - Fix error report and remove unnecessary check in primary_vm_do_failover()
>>   (Dave's suggestion)
>> v11:
>> - Don't call migration_end() in primary_vm_do_failover(),
>>   The cleanup work will be done in migration_thread().
>> - Remove vm_start() in primary_vm_do_failover() which also been done
>>    in migraiton_thread()
>> v10:
>> - Call migration_end() in primary_vm_do_failover()
>>
>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>> ---
>>   include/migration/colo.h     |  3 +++
>>   include/migration/failover.h |  1 +
>>   migration/colo-failover.c    |  7 +++++-
>>   migration/colo.c             | 54 ++++++++++++++++++++++++++++++++++++++++++--
>>   4 files changed, 62 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/migration/colo.h b/include/migration/colo.h
>> index ba27719..0b02e95 100644
>> --- a/include/migration/colo.h
>> +++ b/include/migration/colo.h
>> @@ -32,4 +32,7 @@ void *colo_process_incoming_thread(void *opaque);
>>   bool migration_incoming_in_colo_state(void);
>>
>>   COLOMode get_colo_mode(void);
>> +
>> +/* failover */
>> +void colo_do_failover(MigrationState *s);
>>   #endif
>> diff --git a/include/migration/failover.h b/include/migration/failover.h
>> index 882c625..fba3931 100644
>> --- a/include/migration/failover.h
>> +++ b/include/migration/failover.h
>> @@ -26,5 +26,6 @@ void failover_init_state(void);
>>   int failover_set_state(int old_state, int new_state);
>>   int failover_get_state(void);
>>   void failover_request_active(Error **errp);
>> +bool failover_request_is_active(void);
>>
>>   #endif
>> diff --git a/migration/colo-failover.c b/migration/colo-failover.c
>> index 1b1be24..0c525da 100644
>> --- a/migration/colo-failover.c
>> +++ b/migration/colo-failover.c
>> @@ -32,7 +32,7 @@ static void colo_failover_bh(void *opaque)
>>           error_report("Unkown error for failover, old_state=%d", old_state);
>>           return;
>>       }
>> -    /*TODO: Do failover work */
>> +    colo_do_failover(NULL);
>>   }
>>
>>   void failover_request_active(Error **errp)
>> @@ -67,6 +67,11 @@ int failover_get_state(void)
>>       return atomic_read(&failover_state);
>>   }
>>
>> +bool failover_request_is_active(void)
>> +{
>> +    return ((failover_get_state() != FAILOVER_STATUS_NONE));
>
> You can remove the two sets of brackets.

OK :)

> But other than that:
>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>

Thanks.
Hailiang

>
>> +}
>> +
>>   void qmp_x_colo_lost_heartbeat(Error **errp)
>>   {
>>       if (get_colo_mode() == COLO_MODE_UNKNOWN) {
>> diff --git a/migration/colo.c b/migration/colo.c
>> index 176384e..977c8d8 100644
>> --- a/migration/colo.c
>> +++ b/migration/colo.c
>> @@ -41,6 +41,40 @@ bool migration_incoming_in_colo_state(void)
>>       return mis && (mis->state == MIGRATION_STATUS_COLO);
>>   }
>>
>> +static bool colo_runstate_is_stopped(void)
>> +{
>> +    return runstate_check(RUN_STATE_COLO) || !runstate_is_running();
>> +}
>> +
>> +static void primary_vm_do_failover(void)
>> +{
>> +    MigrationState *s = migrate_get_current();
>> +    int old_state;
>> +
>> +    migrate_set_state(&s->state, MIGRATION_STATUS_COLO,
>> +                      MIGRATION_STATUS_COMPLETED);
>> +
>> +    old_state = failover_set_state(FAILOVER_STATUS_HANDLING,
>> +                                   FAILOVER_STATUS_COMPLETED);
>> +    if (old_state != FAILOVER_STATUS_HANDLING) {
>> +        error_report("Incorrect state (%d) while doing failover for Primary VM",
>> +                     old_state);
>> +        return;
>> +    }
>> +}
>> +
>> +void colo_do_failover(MigrationState *s)
>> +{
>> +    /* Make sure vm stopped while failover */
>> +    if (!colo_runstate_is_stopped()) {
>> +        vm_stop_force_state(RUN_STATE_COLO);
>> +    }
>> +
>> +    if (get_colo_mode() == COLO_MODE_PRIMARY) {
>> +        primary_vm_do_failover();
>> +    }
>> +}
>> +
>>   static int colo_put_cmd(QEMUFile *f, uint32_t cmd)
>>   {
>>       int ret;
>> @@ -150,9 +184,22 @@ static int colo_do_checkpoint_transaction(MigrationState *s,
>>       }
>>
>>       qemu_mutex_lock_iothread();
>> +    if (failover_request_is_active()) {
>> +        qemu_mutex_unlock_iothread();
>> +        ret = -1;
>> +        goto out;
>> +    }
>>       vm_stop_force_state(RUN_STATE_COLO);
>>       qemu_mutex_unlock_iothread();
>>       trace_colo_vm_state_change("run", "stop");
>> +    /*
>> +     * failover request bh could be called after
>> +     * vm_stop_force_state so we check failover_request_is_active() again.
>> +     */
>> +    if (failover_request_is_active()) {
>> +        ret = -1;
>> +        goto out;
>> +    }
>>
>>       /* Disable block migration */
>>       s->params.blk = 0;
>> @@ -248,6 +295,11 @@ static void colo_process_checkpoint(MigrationState *s)
>>       trace_colo_vm_state_change("stop", "run");
>>
>>       while (s->state == MIGRATION_STATUS_COLO) {
>> +        if (failover_request_is_active()) {
>> +            error_report("failover request");
>> +            goto out;
>> +        }
>> +
>>           current_time = qemu_clock_get_ms(QEMU_CLOCK_HOST);
>>           if (current_time - checkpoint_time <
>>               s->parameters[MIGRATION_PARAMETER_X_CHECKPOINT_DELAY]) {
>> @@ -269,8 +321,6 @@ out:
>>       if (ret < 0) {
>>           error_report("%s: %s", __func__, strerror(-ret));
>>       }
>> -    migrate_set_state(&s->state, MIGRATION_STATUS_COLO,
>> -                      MIGRATION_STATUS_COMPLETED);
>>
>>       qsb_free(buffer);
>>       buffer = NULL;
>> --
>> 1.8.3.1
>>
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
> .
>