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

[Hailiang Zhang]

On 2015/12/18 23:35, Dr. David Alan Gilbert wrote:
> * zhanghailiang (address@hidden) 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 <address@hidden>
> > Signed-off-by: Li Zhijian <address@hidden>
> > ---
> > 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 <address@hidden>
> > ---
> >   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 <address@hidden>

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 / address@hidden / Manchester, UK
>
> .