Re: [Qemu-devel] [PATCH v10 20/24] migration: Delay start of migration main routines

[Peter Xu <peterx@redhat.com>]

On Wed, Mar 07, 2018 at 12:00:06PM +0100, Juan Quintela wrote:
> We need to make sure that we have started all the multifd threads.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  migration/migration.c | 4 ++--
>  migration/migration.h | 1 +
>  migration/ram.c       | 3 +++
>  migration/socket.c    | 3 +++
>  4 files changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index c06c34ca0f..a355618220 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -429,7 +429,7 @@ static void migration_incoming_setup(QEMUFile *f)
>      qemu_file_set_blocking(f, false);
>  }
>  
> -static void migration_incoming_process(void)
> +void migration_incoming_process(void)
>  {
>      Coroutine *co = qemu_coroutine_create(process_incoming_migration_co, NULL);
>      qemu_coroutine_enter(co);
> @@ -447,7 +447,7 @@ void migration_ioc_process_incoming(QIOChannel *ioc)
>  
>      if (!mis->from_src_file) {
>          QEMUFile *f = qemu_fopen_channel_input(ioc);
> -        migration_fd_process_incoming(f);
> +        migration_incoming_setup(f);
>          return;
>      }
>      multifd_recv_new_channel(ioc);
> diff --git a/migration/migration.h b/migration/migration.h
> index f40014cf94..03a940831d 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -184,6 +184,7 @@ void migrate_set_state(int *state, int old_state, int new_state);
>  
>  void migration_fd_process_incoming(QEMUFile *f);
>  void migration_ioc_process_incoming(QIOChannel *ioc);
> +void migration_incoming_process(void);
>  
>  bool  migration_has_all_channels(void);
>  
> diff --git a/migration/ram.c b/migration/ram.c
> index 7ef0c2b7e2..1aab96bd5e 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -743,6 +743,9 @@ void multifd_recv_new_channel(QIOChannel *ioc)
>      qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
>                         QEMU_THREAD_JOINABLE);
>      atomic_inc(&multifd_recv_state->count);
> +    if (multifd_recv_state->count == migrate_multifd_channels()) {
> +        migration_incoming_process();
> +    }
>  }
>  
>  /**
> diff --git a/migration/socket.c b/migration/socket.c
> index b3b5571ebb..deda193de7 100644
> --- a/migration/socket.c
> +++ b/migration/socket.c
> @@ -189,6 +189,9 @@ static gboolean socket_accept_incoming_migration(QIOChannel *ioc,
>      if (migration_has_all_channels()) {
>          /* Close listening socket as its no longer needed */
>          qio_channel_close(ioc, NULL);
> +        if (!migrate_use_multifd()) {
> +            migration_incoming_process();

Calling this in socket code seems a bit odd to me.

Can we do something like this?

void migration_ioc_process_incoming(QIOChannel *ioc)
{
    MigrationIncomingState *mis = migration_incoming_get_current();

    if (!mis->from_src_file) {
        /* This is the main channel */
        QEMUFile *f = qemu_fopen_channel_input(ioc);
        migration_incoming_setup(f);
    } else {
        /* This is one of the multifd channels */
        assert(migrate_use_multifd());
        multifd_recv_new_channel(ioc);
    }

    /*
     * Trigger the migration either if:
     * (1) we are not using multifd, or
     * (2) we have setup all the multifd channels
     */
    if (!migrate_use_multifd() || multifd_recv_all_channels_created()) {
        migration_incoming_process();
    }
}

Then we possibly won't need patch 13 as well.  Thanks,

-- 
Peter Xu