Re: [Qemu-devel] [PATCH v3] Move migrate_set_speed and migrate_set_downtime into migrate_set_parameter

[Daniel P. Berrange]

On Mon, Sep 05, 2016 at 07:56:26PM +0530, Ashijeet Acharya wrote:
> Include migrate_set_speed and migrate_set_downtime inside 
> migrate_set_parameters for setting maximum migration speed and expected 
> downtime parameters respectively. Also update the query part for both in qmp 
> and hmp qemu control interfaces.

Please put line breaks in your commit message at 72 characters


Also, when sending v2, v3, etc it is preferred to send it as a new
top-level thread. ie, don't set headers to be a reply to your v1.

> Signed-off-by: Ashijeet Acharya <address@hidden>
> ---
>  hmp.c                         | 33 +++++++++++++++++++++++++++++++++
>  include/migration/migration.h |  1 -
>  migration/migration.c         | 30 ++++++++++++++++++++++++++----
>  qapi-schema.json              | 26 +++++++++++++++++++++++---
>  qmp-commands.hx               | 13 ++++++++++---
>  5 files changed, 92 insertions(+), 11 deletions(-)
> 
> diff --git a/hmp.c b/hmp.c
> index cc2056e..c92769b 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -304,6 +304,12 @@ void hmp_info_migrate_parameters(Monitor *mon, const 
> QDict *qdict)
>          monitor_printf(mon, " %s: '%s'",
>              MigrationParameter_lookup[MIGRATION_PARAMETER_TLS_HOSTNAME],
>              params->tls_hostname ? : "");
> +        monitor_printf(mon, " %s: %" PRId64,
> +            MigrationParameter_lookup[MIGRATION_PARAMETER_MAX_BANDWIDTH],
> +            params->max_bandwidth);
> +        monitor_printf(mon, " %s: %" PRId64,
> +            MigrationParameter_lookup[MIGRATION_PARAMETER_DOWNTIME_LIMIT],
> +            params->downtime_limit);
>          monitor_printf(mon, "\n");
>      }
>  
> @@ -1193,6 +1199,7 @@ void hmp_migrate_incoming(Monitor *mon, const QDict 
> *qdict)
>      hmp_handle_error(mon, &err);
>  }
>  
> +/* Kept for old-commands compatibility */

I don't think this comment really adds any value. Instead, in the qapi
schema, you should mark the legacy methods as deprecated though.

>  void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict)
>  {
>      double value = qdict_get_double(qdict, "value");
> @@ -1211,6 +1218,7 @@ void hmp_migrate_set_cache_size(Monitor *mon, const 
> QDict *qdict)
>      }
>  }
>  
> +/* Kept for old-commands compatibility */
>  void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict)
>  {
>      int64_t value = qdict_get_int(qdict, "value");
> @@ -1251,7 +1259,10 @@ void hmp_migrate_set_parameter(Monitor *mon, const 
> QDict *qdict)
>  {
>      const char *param = qdict_get_str(qdict, "parameter");
>      const char *valuestr = qdict_get_str(qdict, "value");
> +    int64_t valuebw = 0;
> +    double valuedowntime = 0;
>      long valueint = 0;
> +    char *endp;
>      Error *err = NULL;
>      bool has_compress_level = false;
>      bool has_compress_threads = false;
> @@ -1260,6 +1271,8 @@ void hmp_migrate_set_parameter(Monitor *mon, const 
> QDict *qdict)
>      bool has_cpu_throttle_increment = false;
>      bool has_tls_creds = false;
>      bool has_tls_hostname = false;
> +    bool has_max_bandwidth = false;
> +    bool has_downtime_limit = false;
>      bool use_int_value = false;
>      int i;
>  
> @@ -1291,6 +1304,24 @@ void hmp_migrate_set_parameter(Monitor *mon, const 
> QDict *qdict)
>              case MIGRATION_PARAMETER_TLS_HOSTNAME:
>                  has_tls_hostname = true;
>                  break;
> +            case MIGRATION_PARAMETER_MAX_BANDWIDTH:
> +                has_max_bandwidth = true;
> +                valuebw = qemu_strtosz(valuestr, &endp);
> +                if (valuebw < 0 || (size_t)valuebw != valuebw || *endp != 
> '\0'
> +                    || !is_power_of_2(valuebw)) {
> +                    error_setg(&err, "Invalid size %s", valuestr);
> +                    goto cleanup;
> +                }
> +                break;
> +            case MIGRATION_PARAMETER_DOWNTIME_LIMIT:
> +                has_downtime_limit = true;
> +                valuedowntime = strtod(valuestr, &endp);
> +                if (valuestr == endp) {
> +                    error_setg(&err, "Unable to parse '%s' as a number",
> +                               valuestr);
> +                    goto cleanup;
> +                }
> +                break;
>              }
>  
>              if (use_int_value) {
> @@ -1308,6 +1339,8 @@ void hmp_migrate_set_parameter(Monitor *mon, const 
> QDict *qdict)
>                                         has_cpu_throttle_increment, valueint,
>                                         has_tls_creds, valuestr,
>                                         has_tls_hostname, valuestr,
> +                                       has_max_bandwidth, valuebw,
> +                                       has_downtime_limit, valuedowntime,
>                                         &err);
>              break;
>          }
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index 3c96623..a5429ee 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -129,7 +129,6 @@ struct MigrationSrcPageRequest {
>  
>  struct MigrationState
>  {
> -    int64_t bandwidth_limit;
>      size_t bytes_xfer;
>      size_t xfer_limit;
>      QemuThread thread;
> diff --git a/migration/migration.c b/migration/migration.c
> index 955d5ee..4b54b58 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -44,6 +44,9 @@
>  #define BUFFER_DELAY     100
>  #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
>  
> +/* Amount of nanoseconds we are willing to wait for migration to be down. */
> +#define DEFAULT_MIGRATE_SET_DOWNTIME 300000000
> +
>  /* Default compression thread count */
>  #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
>  /* Default decompression thread count, usually decompression is at
> @@ -80,7 +83,6 @@ MigrationState *migrate_get_current(void)
>      static bool once;
>      static MigrationState current_migration = {
>          .state = MIGRATION_STATUS_NONE,
> -        .bandwidth_limit = MAX_THROTTLE,
>          .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
>          .mbps = -1,
>          .parameters = {
> @@ -89,6 +91,8 @@ MigrationState *migrate_get_current(void)
>              .decompress_threads = DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT,
>              .cpu_throttle_initial = DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL,
>              .cpu_throttle_increment = DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT,
> +            .max_bandwidth = MAX_THROTTLE,
> +            .downtime_limit = DEFAULT_MIGRATE_SET_DOWNTIME,
>          },
>      };
>  
> @@ -566,6 +570,8 @@ MigrationParameters *qmp_query_migrate_parameters(Error 
> **errp)
>      params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
>      params->tls_creds = g_strdup(s->parameters.tls_creds);
>      params->tls_hostname = g_strdup(s->parameters.tls_hostname);
> +    params->max_bandwidth = s->parameters.max_bandwidth;
> +    params->downtime_limit = s->parameters.downtime_limit;
>  
>      return params;
>  }
> @@ -773,6 +779,10 @@ void qmp_migrate_set_parameters(bool has_compress_level,
>                                  const char *tls_creds,
>                                  bool has_tls_hostname,
>                                  const char *tls_hostname,
> +                                bool has_max_bandwidth,
> +                                int64_t max_bandwidth,
> +                                bool has_downtime_limit,
> +                                double downtime_limit,
>                                  Error **errp)
>  {
>      MigrationState *s = migrate_get_current();
> @@ -832,6 +842,12 @@ void qmp_migrate_set_parameters(bool has_compress_level,
>          g_free(s->parameters.tls_hostname);
>          s->parameters.tls_hostname = g_strdup(tls_hostname);
>      }
> +    if (has_max_bandwidth) {
> +        qmp_migrate_set_speed(max_bandwidth, NULL);
> +    }
> +    if (has_downtime_limit) {
> +        qmp_migrate_set_downtime(downtime_limit, NULL);
> +    }
>  }
>  
>  
> @@ -1175,18 +1191,24 @@ void qmp_migrate_set_speed(int64_t value, Error 
> **errp)
>      }
>  
>      s = migrate_get_current();
> -    s->bandwidth_limit = value;
> +    s->parameters.max_bandwidth = value;
>      if (s->to_dst_file) {
>          qemu_file_set_rate_limit(s->to_dst_file,
> -                                 s->bandwidth_limit / XFER_LIMIT_RATIO);
> +                            s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
>      }
>  }
>  
>  void qmp_migrate_set_downtime(double value, Error **errp)
>  {
> +    MigrationState *s;
> +
>      value *= 1e9;
>      value = MAX(0, MIN(UINT64_MAX, value));
> +
> +    s = migrate_get_current();
> +
>      max_downtime = (uint64_t)value;
> +    s->parameters.downtime_limit = max_downtime;
>  }
>  
>  bool migrate_postcopy_ram(void)
> @@ -1858,7 +1880,7 @@ void migrate_fd_connect(MigrationState *s)
>  
>      qemu_file_set_blocking(s->to_dst_file, true);
>      qemu_file_set_rate_limit(s->to_dst_file,
> -                             s->bandwidth_limit / XFER_LIMIT_RATIO);
> +                             s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
>  
>      /* Notify before starting migration thread */
>      notifier_list_notify(&migration_state_notifiers, s);
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 5658723..250eac5 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -637,12 +637,18 @@
>  #                hostname must be provided so that the server's x509
>  #                certificate identity can be validated. (Since 2.7)
>  #
> +# @max-bandwidth: to set maximum speed for migration. A value lesser than
> +#                     zero will be automatically round upto zero. Since 2.8)

Document the units for this ? eg is it bits-per-second, kb-per-second,
mb-per-second, etc

> +#
> +# @downtime-limit: set maximum tolerated downtime for migration. Since 2.8)

Again, units ? nanoseconds ? milliseconds ?

> +#
>  # Since: 2.4
>  ##
>  { 'enum': 'MigrationParameter',
>    'data': ['compress-level', 'compress-threads', 'decompress-threads',
>             'cpu-throttle-initial', 'cpu-throttle-increment',
> -           'tls-creds', 'tls-hostname'] }
> +           'tls-creds', 'tls-hostname', 'max-bandwidth',
> +           'downtime-limit'] }
>  
>  #
>  # @migrate-set-parameters
> @@ -678,6 +684,11 @@
>  #                hostname must be provided so that the server's x509
>  #                certificate identity can be validated. (Since 2.7)
>  #
> +# @max-bandwidth: to set maximum speed for migration. A value lesser than
> +#                     zero will be automatically round upto zero. Since 2.8)

Units

> +#
> +# @downtime-limit: set maximum tolerated downtime for migration. Since 2.8)

Units

> +#
>  # Since: 2.4
>  ##
>  { 'command': 'migrate-set-parameters',
> @@ -687,7 +698,9 @@
>              '*cpu-throttle-initial': 'int',
>              '*cpu-throttle-increment': 'int',
>              '*tls-creds': 'str',
> -            '*tls-hostname': 'str'} }
> +            '*tls-hostname': 'str',
> +            '*max-bandwidth': 'int',
> +            '*downtime-limit': 'number'} }
>  
>  #
>  # @MigrationParameters
> @@ -721,6 +734,11 @@
>  #                hostname must be provided so that the server's x509
>  #                certificate identity can be validated. (Since 2.7)
>  #
> +# @max-bandwidth: to set maximum speed for migration. A value lesser than
> +#                     zero will be automatically round upto zero. (Since 2.8)
> +#
> +# @downtime-limit: set maximum tolerated downtime for migration. Since 2.8)
> +#
>  # Since: 2.4
>  ##
>  { 'struct': 'MigrationParameters',
> @@ -730,7 +748,9 @@
>              'cpu-throttle-initial': 'int',
>              'cpu-throttle-increment': 'int',
>              'tls-creds': 'str',
> -            'tls-hostname': 'str'} }
> +            'tls-hostname': 'str',
> +            'max-bandwidth': 'int',
> +            'downtime-limit': 'int'} }
>  ##
>  # @query-migrate-parameters
>  #
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 6866264..0418cab 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -3790,7 +3790,9 @@ Set migration parameters
>                            throttled for auto-converge (json-int)
>  - "cpu-throttle-increment": set throttle increasing percentage for
>                              auto-converge (json-int)
> -
> +- "max-bandwidth": set maximum speed for migrations (json-int)

Document units

> +- "downtime-limit": set maximum tolerated downtime (in seconds) for
> +                          migrations (json-number)

I'm sure units for this are not "seconds" as that is way too coarse.

>  Arguments:
>  
>  Example:
> @@ -3803,7 +3805,7 @@ EQMP
>      {
>          .name       = "migrate-set-parameters",
>          .args_type  =
> -            
> "compress-level:i?,compress-threads:i?,decompress-threads:i?,cpu-throttle-initial:i?,cpu-throttle-increment:i?",
> +            
> "compress-level:i?,compress-threads:i?,decompress-threads:i?,cpu-throttle-initial:i?,cpu-throttle-increment:i?,max-bandwidth:i?,downtime-limit:T?",
>          .mhandler.cmd_new = qmp_marshal_migrate_set_parameters,
>      },
>  SQMP
> @@ -3820,6 +3822,9 @@ Query current migration parameters
>                                      throttled (json-int)
>           - "cpu-throttle-increment" : throttle increasing percentage for
>                                        auto-converge (json-int)
> +         - "max-bandwidth" : maximium migration speed (json-int)
> +         - "downtime-limit" : maximum tolerated downtime of migration
> +                                      (json-int)

Document units


Regards,
Daniel
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