Re: [Qemu-devel] [PATCH 2/5] Split out end of migration code from migration_thread

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

On 2015/8/13 18:51, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
>
> The code that gets run at the end of the migration process
> is getting large, and I'm about to add more for postcopy.
> Split it into a separate function.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---

Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com>

>   migration/migration.c | 75 ++++++++++++++++++++++++++++++++-------------------
>   trace-events          |  2 ++
>   2 files changed, 49 insertions(+), 28 deletions(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 662e77e..46bb410 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -913,6 +913,50 @@ int64_t migrate_xbzrle_cache_size(void)
>       return s->xbzrle_cache_size;
>   }
>
> +/**
> + * migration_completion: Used by migration_thread when there's not much left.
> + *   The caller 'breaks' the loop when this returns.
> + *
> + * @s: Current migration state
> + * @*old_vm_running: Pointer to old_vm_running flag
> + * @*start_time: Pointer to time to update
> + */
> +static void migration_completion(MigrationState *s, bool *old_vm_running,
> +                                 int64_t *start_time)
> +{
> +    int ret;
> +
> +    qemu_mutex_lock_iothread();
> +    *start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
> +    qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
> +    *old_vm_running = runstate_is_running();
> +
> +    ret = global_state_store();
> +    if (!ret) {
> +        ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
> +        if (ret >= 0) {
> +            qemu_file_set_rate_limit(s->file, INT64_MAX);
> +            qemu_savevm_state_complete(s->file);
> +        }
> +    }
> +    qemu_mutex_unlock_iothread();
> +
> +    if (ret < 0) {
> +        goto fail;
> +    }
> +
> +    if (qemu_file_get_error(s->file)) {
> +        trace_migration_completion_file_err();
> +        goto fail;
> +    }
> +
> +    migrate_set_state(s, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_COMPLETED);
> +    return;
> +
> +fail:
> +    migrate_set_state(s, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_FAILED);
> +}
> +
>   /* migration thread support */
>
>   static void *migration_thread(void *opaque)
> @@ -943,34 +987,9 @@ static void *migration_thread(void *opaque)
>               if (pending_size && pending_size >= max_size) {
>                   qemu_savevm_state_iterate(s->file);
>               } else {
> -                int ret;
> -
> -                qemu_mutex_lock_iothread();
> -                start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
> -                qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
> -                old_vm_running = runstate_is_running();
> -
> -                ret = global_state_store();
> -                if (!ret) {
> -                    ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
> -                    if (ret >= 0) {
> -                        qemu_file_set_rate_limit(s->file, INT64_MAX);
> -                        qemu_savevm_state_complete(s->file);
> -                    }
> -                }
> -                qemu_mutex_unlock_iothread();
> -
> -                if (ret < 0) {
> -                    migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
> -                                      MIGRATION_STATUS_FAILED);
> -                    break;
> -                }
> -
> -                if (!qemu_file_get_error(s->file)) {
> -                    migrate_set_state(s, MIGRATION_STATUS_ACTIVE,
> -                                      MIGRATION_STATUS_COMPLETED);
> -                    break;
> -                }
> +                trace_migration_thread_low_pending(pending_size);
> +                migration_completion(s, &old_vm_running, &start_time);
> +                break;
>               }
>           }
>
> diff --git a/trace-events b/trace-events
> index 94bf3bb..1509e5b 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1406,6 +1406,8 @@ migrate_transferred(uint64_t tranferred, uint64_t time_spent, double bandwidth,
>   migrate_state_too_big(void) ""
>   migrate_global_state_post_load(const char *state) "loaded state: %s"
>   migrate_global_state_pre_save(const char *state) "saved state: %s"
> +migration_completion_file_err(void) ""
> +migration_thread_low_pending(uint64_t pending) "%" PRIu64
>
>   # migration/rdma.c
>   qemu_rdma_accept_incoming_migration(void) ""
>