Re: [PATCH 1/5] migration: add trace point when vm_stop_force_state fails

[Dr. David Alan Gilbert]

* Daniel P. Berrangé (berrange@redhat.com) wrote:
> This is a critical failure scenario for migration that is hard to
> diagnose from existing probes. Most likely it is caused by an error
> from bdrv_flush(), but we're not logging the errno anywhere, hence
> this new probe.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

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

> ---
>  migration/migration.c  | 1 +
>  migration/trace-events | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 8ca034136b..bee0dcd501 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -3121,6 +3121,7 @@ static void migration_completion(MigrationState *s)
>          if (!ret) {
>              bool inactivate = !migrate_colo_enabled();
>              ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
> +            trace_migration_completion_vm_stop(ret);
>              if (ret >= 0) {
>                  ret = migration_maybe_pause(s, &current_active_state,
>                                              MIGRATION_STATUS_DEVICE);
> diff --git a/migration/trace-events b/migration/trace-events
> index 668c562fed..8ec28432eb 100644
> --- a/migration/trace-events
> +++ b/migration/trace-events
> @@ -149,6 +149,7 @@ migrate_pending(uint64_t size, uint64_t max, uint64_t 
> pre, uint64_t compat, uint
>  migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
>  migrate_send_rp_recv_bitmap(char *name, int64_t size) "block '%s' size 
> 0x%"PRIi64
>  migration_completion_file_err(void) ""
> +migration_completion_vm_stop(int ret) "ret %d"
>  migration_completion_postcopy_end(void) ""
>  migration_completion_postcopy_end_after_complete(void) ""
>  migration_rate_limit_pre(int ms) "%d ms"
> -- 
> 2.30.2
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK