Re: [Qemu-devel] [PATCH 6/6] qapi: Convert migrate

[Jan Kiszka]

On 2012-02-10 20:31, Luiz Capitulino wrote:
> The migrate command is one of those commands where HMP and QMP completely
> mix up together. This made the conversion to the QAPI (which separates the
> command into QMP and HMP parts) a bit difficult.
> 
> The first important change to be noticed is that this commit completes the
> removal of the Monitor object from migration code, started by the previous
> commit.
> 
> Another important and tricky change is about supporting the non-detached
> mode. That's, if the user doesn't pass '-d' the migrate command will lock
> the monitor and will only release it when migration is finished.
> 
> To support that in the new HMP command (hmp_migrate()), it was necessary
> to create a timer which runs every second and checks if the migration is
> still active. If it's, the timer callback will re-schedule itself to run
> one second in the future. If the migration has already finished, the
> monitor lock is relased and the user can use it normally.
> 
> All these changes should be transparent to the user.
> 
> Signed-off-by: Anthony Liguori <address@hidden>
> Signed-off-by: Luiz Capitulino <address@hidden>
> ---
>  hmp-commands.hx  |    3 +-
>  hmp.c            |   51 +++++++++++++++++++++++++++++++++++++++++
>  hmp.h            |    1 +
>  migration-fd.c   |    2 +-
>  migration.c      |   66 
> ++++++++++++++----------------------------------------
>  migration.h      |    3 --
>  qapi-schema.json |   21 +++++++++++++++++
>  qmp-commands.hx  |    9 +------
>  savevm.c         |   13 +++++-----
>  sysemu.h         |    2 +-
>  10 files changed, 100 insertions(+), 71 deletions(-)
> 
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 573b823..10d3f1b 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -792,8 +792,7 @@ ETEXI
>                     " full copy of disk\n\t\t\t -i for migration without "
>                     "shared storage with incremental copy of disk "
>                     "(base image shared between src and destination)",
> -        .user_print = monitor_user_noop,     
> -     .mhandler.cmd_new = do_migrate,
> +        .mhandler.cmd = hmp_migrate,
>      },
>  
>  
> diff --git a/hmp.c b/hmp.c
> index 8ff8c94..70bd574 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -14,6 +14,7 @@
>   */
>  
>  #include "hmp.h"
> +#include "qemu-timer.h"
>  #include "qmp-commands.h"
>  
>  static void hmp_handle_error(Monitor *mon, Error **errp)
> @@ -851,3 +852,53 @@ void hmp_block_job_cancel(Monitor *mon, const QDict 
> *qdict)
>  
>      hmp_handle_error(mon, &error);
>  }
> +
> +typedef struct MigrationStatus
> +{
> +    QEMUTimer *timer;
> +    Monitor *mon;
> +} MigrationStatus;
> +
> +static void hmp_migrate_status_cb(void *opaque)
> +{
> +    MigrationStatus *status = opaque;
> +    MigrationInfo *info;
> +
> +    info = qmp_query_migrate(NULL);
> +    if (!info->has_status || strcmp(info->status, "active") == 0) {
> +        qemu_mod_timer(status->timer, qemu_get_clock_ms(rt_clock) + 1000);
> +        goto out;
> +    }
> +
> +    monitor_resume(status->mon);

status->mon can be NULL if suspend is not supported, see below.

> +    qemu_del_timer(status->timer);
> +    g_free(status);
> +
> +out:
> +    qapi_free_MigrationInfo(info);
> +}
> +
> +void hmp_migrate(Monitor *mon, const QDict *qdict)
> +{
> +    int detach = qdict_get_try_bool(qdict, "detach", 0);
> +    int blk = qdict_get_try_bool(qdict, "blk", 0);
> +    int inc = qdict_get_try_bool(qdict, "inc", 0);
> +    const char *uri = qdict_get_str(qdict, "uri");
> +    Error *err = NULL;
> +
> +    qmp_migrate(uri, !!blk, blk, !!inc, inc, false, false, &err);
> +    if (err) {
> +        monitor_printf(mon, "migrate: %s\n", error_get_pretty(err));
> +        error_free(err);
> +        return;
> +    }
> +
> +    if (!detach) {
> +        MigrationStatus *status = g_malloc0(sizeof(*status));
> +        status->timer = qemu_new_timer_ms(rt_clock, hmp_migrate_status_cb,
> +                                          status);
> +        status->mon = mon;
> +        monitor_suspend(mon);

Lacks return code check and handling, see original version.

> +        qemu_mod_timer(status->timer, qemu_get_clock_ms(rt_clock));
> +    }
> +}

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux