Re: [Qemu-devel] [PATCH 10/18] migration-local: implementation of outgoing part

["Michael R. Hines" <mrhines@linux.vnet.ibm.com>]

On 08/21/2013 03:18 AM, Lei Li wrote:
> Implementation of outgoing part for localhost migration.
> The integration of migration thread and corresponding
> adjustment will be in coming patches.
>
> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
> ---
>   include/migration/migration.h |    2 +
>   migration-local.c             |   85 +++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 87 insertions(+), 0 deletions(-)
>
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index 5336117..d2c7eff 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -92,6 +92,8 @@ void rdma_start_outgoing_migration(void *opaque, const char *host_port, Error **
>
>   void rdma_start_incoming_migration(const char *host_port, Error **errp);
>
> +void local_start_outgoing_migration(void *opaque, const char *uri, Error **errp);
> +
>   void migrate_fd_error(MigrationState *s);
>
>   void migrate_fd_connect(MigrationState *s);
> diff --git a/migration-local.c b/migration-local.c
> index 93190fd..cf4a091 100644
> --- a/migration-local.c
> +++ b/migration-local.c
> @@ -209,3 +209,88 @@ static void *qemu_fopen_local(int fd, const char *mode)
>
>       return s->file;
>   }
> +
> +/************************************************************************
> + * Outgoing part
> + **/
> +
> +static QEMUFileLocal *local_migration_init(void)
> +{
> +    QEMUFileLocal *s = g_malloc0(sizeof(*s));
> +
> +    s->state = MIG_STATE_SETUP;
> +    trace_migrate_set_state(MIG_STATE_SETUP);
> +    s->fd = -1;
> +    s->last_block_sent = NULL;
> +
> +    return s;
> +}
> +

migration.c already does this. Is there some reason why you need to 
access the state machine?

If you have a custom initial values, you should change 
migrate_get_current, not create your own init().


> +static void unix_local_wait_for_connect(int fd, void *opaque)
> +{
> +    MigrationState *s = opaque;
> +
> +    if (fd < 0) {
> +        DPRINTF("migrate connect error\n");
> +        s->file = NULL;
> +        migrate_fd_error(s);
> +    } else {
> +        DPRINTF("migrate connect success\n");
> +        s->file = qemu_fopen_local(fd, "wb");
> +        migrate_fd_connect(s);
> +    }
> +}
> +
> +static void unix_local_outgoing_connect(MigrationState *s, const char *path,
> +                                        Error **errp)
> +{
> +    unix_nonblocking_connect(path, unix_local_wait_for_connect, s, errp);
> +}
> +
> +void local_start_outgoing_migration(void *opaque, const char *uri,
> +                                    Error **errp)
> +{
> +    MigrationState *s = opaque;
> +    const char *path;
> +    QEMUFileLocal *local;
> +    Error *local_err = NULL;
> +    int is_vm_running;
> +    int ret;
> +
> +    local = local_migration_init();
> +    if (local == NULL) {
> +        error_setg(errp, "Failed to initialize\n");
> +    }
> +
> +    bdrv_flush_all();
> +
> +    is_vm_running = runstate_is_running();
> +
> +    /* Stop the VM first */
> +    if (is_vm_running) {
> +        ret = vm_stop(RUN_STATE_SAVE_VM);
> +        if (ret < 0) {
> +            goto fail;
> +        }
> +    }
> +

What is this for? The migration_thread() already does this work for you.....

Are you trying to avoid pre-copy? Pre-copy should not be bad for you.

> +    /* Start outgoing migration via unix socket. */
> +    if (uri) {
> +        /* XXX. Creation of a new unix_start_outgoing_migration_* is
> +         * not necessary, just for the first step. This will be replaced
> +         * by vmsplice mechanism.
> +         **/
> +        unix_local_outgoing_connect(s, path, &local_err);
> +    } else {
> +        error_set(errp, QERR_INVALID_PARAMETER_VALUE,
> +                  "uri", "a valid migration protocol");
> +        goto fail;
> +    }
> +
> +    return;
> +
> +fail:
> +    error_propagate(errp, local_err);
> +    g_free(local);
> +    migrate_fd_error(s);
> +}