Re: [Qemu-devel] [PATCH COLO-Frame v10 05/38] migration: Integrate COLO checkpoint process into migration

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* zhanghailiang (zhang.zhanghailiang@huawei.com) wrote:
> Add a migrate state: MIGRATION_STATUS_COLO, enter this migration state
> after the first live migration successfully finished.
> 
> We reuse migration thread, so if colo is enabled by user, migration thread will
> go into the process of colo.
> 
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
> v10: Simplify process by dropping colo thread and reusing migration thread.
>      (Dave's suggestion)
> ---
>  include/migration/colo.h |  3 +++
>  migration/colo.c         | 31 +++++++++++++++++++++++++++++++
>  migration/migration.c    | 19 +++++++++++++++----
>  qapi-schema.json         |  2 +-
>  stubs/migration-colo.c   |  9 +++++++++
>  trace-events             |  3 +++
>  6 files changed, 62 insertions(+), 5 deletions(-)
> 
> diff --git a/include/migration/colo.h b/include/migration/colo.h
> index 9b6662d..f462f06 100644
> --- a/include/migration/colo.h
> +++ b/include/migration/colo.h
> @@ -19,4 +19,7 @@
>  bool colo_supported(void);
>  void colo_info_mig_init(void);
>  
> +void migrate_start_colo_process(MigrationState *s);
> +bool migration_in_colo_state(void);
> +
>  #endif
> diff --git a/migration/colo.c b/migration/colo.c
> index 2c40d2e..cf0ccb8 100644
> --- a/migration/colo.c
> +++ b/migration/colo.c
> @@ -10,9 +10,40 @@
>   * later.  See the COPYING file in the top-level directory.
>   */
>  
> +#include "sysemu/sysemu.h"
>  #include "migration/colo.h"
> +#include "trace.h"
>  
>  bool colo_supported(void)
>  {
>      return true;
>  }
> +
> +bool migration_in_colo_state(void)
> +{
> +    MigrationState *s = migrate_get_current();
> +
> +    return (s->state == MIGRATION_STATUS_COLO);
> +}
> +
> +static void colo_process_checkpoint(MigrationState *s)
> +{
> +    qemu_mutex_lock_iothread();
> +    vm_start();
> +    qemu_mutex_unlock_iothread();
> +    trace_colo_vm_state_change("stop", "run");
> +
> +    /*TODO: COLO checkpoint savevm loop*/
> +
> +    migrate_set_state(&s->state, MIGRATION_STATUS_COLO,
> +                      MIGRATION_STATUS_COMPLETED);
> +}
> +
> +void migrate_start_colo_process(MigrationState *s)
> +{
> +    qemu_mutex_unlock_iothread();
> +    migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
> +                      MIGRATION_STATUS_COLO);
> +    colo_process_checkpoint(s);
> +    qemu_mutex_lock_iothread();
> +}
> diff --git a/migration/migration.c b/migration/migration.c
> index b179464..cf83531 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -475,6 +475,10 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>  
>          get_xbzrle_cache_stats(info);
>          break;
> +    case MIGRATION_STATUS_COLO:
> +        info->has_status = true;
> +        /* TODO: display COLO specific information (checkpoint info etc.) */
> +        break;
>      case MIGRATION_STATUS_COMPLETED:
>          get_xbzrle_cache_stats(info);
>  
> @@ -793,7 +797,8 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
>  
>      if (s->state == MIGRATION_STATUS_ACTIVE ||
>          s->state == MIGRATION_STATUS_SETUP ||
> -        s->state == MIGRATION_STATUS_CANCELLING) {
> +        s->state == MIGRATION_STATUS_CANCELLING ||
> +        s->state == MIGRATION_STATUS_COLO) {
>          error_setg(errp, QERR_MIGRATION_ACTIVE);
>          return;
>      }
> @@ -1030,8 +1035,11 @@ static void migration_completion(MigrationState *s, bool *old_vm_running,
>          goto fail;
>      }
>  
> -    migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
> -                      MIGRATION_STATUS_COMPLETED);
> +    if (!migrate_colo_enabled()) {
> +        migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
> +                          MIGRATION_STATUS_COMPLETED);
> +    }
> +
>      return;
>  
>  fail:
> @@ -1056,6 +1064,7 @@ static void *migration_thread(void *opaque)
>      int64_t max_size = 0;
>      int64_t start_time = initial_time;
>      bool old_vm_running = false;
> +    bool enable_colo = migrate_colo_enabled();
>  
>      rcu_register_thread();
>  
> @@ -1130,7 +1139,9 @@ static void *migration_thread(void *opaque)
>          }
>          runstate_set(RUN_STATE_POSTMIGRATE);
>      } else {
> -        if (old_vm_running) {
> +        if (s->state == MIGRATION_STATUS_ACTIVE && enable_colo) {
> +            migrate_start_colo_process(s);
> +        } else if (old_vm_running) {
>              vm_start();
>          }
>      }
> diff --git a/qapi-schema.json b/qapi-schema.json
> index cb5e5fd..22251ec 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -439,7 +439,7 @@
>  ##
>  { 'enum': 'MigrationStatus',
>    'data': [ 'none', 'setup', 'cancelling', 'cancelled',
> -            'active', 'completed', 'failed' ] }
> +            'active', 'completed', 'failed', 'colo' ] }
>  
>  ##
>  # @MigrationInfo
> diff --git a/stubs/migration-colo.c b/stubs/migration-colo.c
> index 3d817df..acddca6 100644
> --- a/stubs/migration-colo.c
> +++ b/stubs/migration-colo.c
> @@ -16,3 +16,12 @@ bool colo_supported(void)
>  {
>      return false;
>  }
> +
> +bool migration_in_colo_state(void)
> +{
> +    return false;
> +}
> +
> +void migrate_start_colo_process(MigrationState *s)
> +{
> +}
> diff --git a/trace-events b/trace-events
> index 72136b9..9cd6391 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1497,6 +1497,9 @@ rdma_start_incoming_migration_after_rdma_listen(void) ""
>  rdma_start_outgoing_migration_after_rdma_connect(void) ""
>  rdma_start_outgoing_migration_after_rdma_source_init(void) ""
>  
> +# migration/colo.c
> +colo_vm_state_change(const char *old, const char *new) "Change '%s' => '%s'"
> +
>  # kvm-all.c
>  kvm_ioctl(int type, void *arg) "type 0x%x, arg %p"
>  kvm_vm_ioctl(int type, void *arg) "type 0x%x, arg %p"
> -- 
> 1.8.3.1
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK