Re: [PULL 5/5] migration: simplify migration_iteration_run()

[Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>]

On 30.01.23 11:03, Juan Quintela wrote:
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>   migration/migration.c | 24 ++++++++++++------------
>   1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 594a42f085..644c61e91d 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -3764,23 +3764,23 @@ static MigIterateState migration_iteration_run(MigrationState *s)
>                                       pend_pre, pend_compat, pend_post);
>       }
>   
> -    if (pending_size && pending_size >= s->threshold_size) {
> -        /* Still a significant amount to transfer */
> -        if (!in_postcopy && pend_pre <= s->threshold_size &&
> -            qatomic_read(&s->start_postcopy)) {
> -            if (postcopy_start(s)) {
> -                error_report("%s: postcopy failed to start", __func__);
> -            }
> -            return MIG_ITERATE_SKIP;
> -        }
> -        /* Just another iteration step */
> -        qemu_savevm_state_iterate(s->to_dst_file, in_postcopy);
> -    } else {
> +    if (pending_size < s->threshold_size) {

to keep the logic, formally it should be "if (!pending_size || pending_size < s->threshold_size)"...

Actually, could s->threshold_size be 0 here? Or, worth an assertion assert(s->threshold_size) ?

>           trace_migration_thread_low_pending(pending_size);
>           migration_completion(s);
>           return MIG_ITERATE_BREAK;
>       }
>   
> +    /* Still a significant amount to transfer */
> +    if (!in_postcopy && pend_pre <= s->threshold_size &&
> +        qatomic_read(&s->start_postcopy)) {
> +        if (postcopy_start(s)) {
> +            error_report("%s: postcopy failed to start", __func__);
> +        }
> +        return MIG_ITERATE_SKIP;
> +    }
> +
> +    /* Just another iteration step */
> +    qemu_savevm_state_iterate(s->to_dst_file, in_postcopy);
>       return MIG_ITERATE_RESUME;
>   }
>   

-- 
Best regards,
Vladimir