Re: [PATCH 15/20] migration: Allow migrate-recover to run multiple times

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

* Peter Xu (peterx@redhat.com) wrote:
> Previously migration didn't have an easy way to cleanup the listening
> transport, migrate recovery only allows to execute once.  That's done with a
> trick flag in postcopy_recover_triggered.
> 
> Now the facility is already there.
> 
> Drop postcopy_recover_triggered and instead allows a new migrate-recover to
> release the previous listener transport.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>

OK, was that the only reason you couldn't recover twice?


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

> ---
>  migration/migration.c | 13 ++-----------
>  migration/migration.h |  1 -
>  migration/savevm.c    |  3 ---
>  3 files changed, 2 insertions(+), 15 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 6bb321cdd3..16086897aa 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2159,11 +2159,8 @@ void qmp_migrate_recover(const char *uri, Error **errp)
>          return;
>      }
>  
> -    if (qatomic_cmpxchg(&mis->postcopy_recover_triggered,
> -                       false, true) == true) {
> -        error_setg(errp, "Migrate recovery is triggered already");
> -        return;
> -    }
> +    /* If there's an existing transport, release it */
> +    migration_incoming_transport_cleanup(mis);
>  
>      /*
>       * Note that this call will never start a real migration; it will
> @@ -2171,12 +2168,6 @@ void qmp_migrate_recover(const char *uri, Error **errp)
>       * to continue using that newly established channel.
>       */
>      qemu_start_incoming_migration(uri, errp);
> -
> -    /* Safe to dereference with the assert above */
> -    if (*errp) {
> -        /* Reset the flag so user could still retry */
> -        qatomic_set(&mis->postcopy_recover_triggered, false);
> -    }
>  }
>  
>  void qmp_migrate_pause(Error **errp)
> diff --git a/migration/migration.h b/migration/migration.h
> index f17ccc657c..a863032b71 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -139,7 +139,6 @@ struct MigrationIncomingState {
>      struct PostcopyBlocktimeContext *blocktime_ctx;
>  
>      /* notify PAUSED postcopy incoming migrations to try to continue */
> -    bool postcopy_recover_triggered;
>      QemuSemaphore postcopy_pause_sem_dst;
>      QemuSemaphore postcopy_pause_sem_fault;
>  
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 967ff80547..254aa78234 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2589,9 +2589,6 @@ static bool postcopy_pause_incoming(MigrationIncomingState *mis)
>  
>      assert(migrate_postcopy_ram());
>  
> -    /* Clear the triggered bit to allow one recovery */
> -    mis->postcopy_recover_triggered = false;
> -
>      /*
>       * Unregister yank with either from/to src would work, since ioc behind it
>       * is the same
> -- 
> 2.32.0
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK