Re: [Qemu-devel] [PATCH v2] hmp, qmp: introduce "info memory" and "query-memory" commands

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

* Vadim Galitsyn (vadim.galitsyn@profitbricks.com) wrote:
> Commands above provide the following memory information in bytes:
> 
>   * base-memory - amount of static memory specified
>     with '-m' option at the start of the QEMU process.
> 
>   * hot-plug-memory - amount of memory that was hot-plugged.
> 
>   * ballooned-actual-memory - size of the memory that remains
>     available to the guest after ballooning, as reported by the
>     guest. If the guest has not reported its memory, this value
>     equals to @base-memory + @hot-plug-memory. If ballooning
>     is not enabled, zero value is reported.
> 
> NOTE:
> 
>     Parameter @ballooned-actual-memory reports the same as
>     "info balloon" command when ballooning is enabled. The idea
>     to have it in scope of this command(s) comes from
>     https://lists.gnu.org/archive/html/qemu-devel/2012-07/msg01472.html.
> 
> Signed-off-by: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
> Signed-off-by: Mohammed Gamal <mohammed.gamal@profitbricks.com>
> Signed-off-by: Eduardo Otubo <eduardo.otubo@profitbricks.com>
> Signed-off-by: Vadim Galitsyn <vadim.galitsyn@profitbricks.com>
> Reviewed-by: Eugene Crosser <evgenii.cherkashin@profitbricks.com>
> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Cc: Markus Armbruster <armbru@redhat.com>
> Cc: qemu-devel@nongnu.org
> ---
> 
> v2:
>  * Fixed build for targets which do not have CONFIG_MEM_HOTPLUG enabled.
> 
>  hmp-commands-info.hx | 15 +++++++++++++++
>  hmp.c                | 14 ++++++++++++++
>  hmp.h                |  1 +
>  qapi-schema.json     | 27 +++++++++++++++++++++++++++
>  qmp.c                | 34 ++++++++++++++++++++++++++++++++++
>  5 files changed, 91 insertions(+)
> 
> diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> index ae169011b1..bc37525550 100644
> --- a/hmp-commands-info.hx
> +++ b/hmp-commands-info.hx
> @@ -833,6 +833,21 @@ STEXI
>  @end table
>  ETEXI
>  
> +STEXI
> +@item info memory
> +@findex memory
> +Display total memory size in bytes (static, hotplugged, ballooned)
> +ETEXI
> +
> +    {
> +        .name       = "memory",
> +        .args_type  = "",
> +        .params     = "",
> +        .help       = "show memory size information in bytes (static, "
> +                      "hotplugged, ballooned)",
> +        .cmd        = hmp_info_memory,
> +    },
> +
>  STEXI
>  @end table
>  ETEXI
> diff --git a/hmp.c b/hmp.c
> index 8c72c58b20..81e383f169 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -2817,3 +2817,17 @@ void hmp_info_vm_generation_id(Monitor *mon, const QDict *qdict)
>      hmp_handle_error(mon, &err);
>      qapi_free_GuidInfo(info);
>  }
> +
> +void hmp_info_memory(Monitor *mon, const QDict *qdict)
> +{
> +    Error *err = NULL;
> +    MemoryInfo *info = qmp_query_memory(&err);
> +    if (info) {
> +        monitor_printf(mon, "base-memory: %lu\n", info->base_memory);
> +        monitor_printf(mon, "hot-plug-memory: %lu\n", info->hot_plug_memory);
> +        monitor_printf(mon, "ballooned-actual-memory: %lu\n",
> +                       info->ballooned_actual_memory);

I think you need to use the PRIu64 macros rather than 'lu' for the types
of the ints there to keep it portable.

Other than that; please add a test entry to tests/test-hmp.c
and I'm guessing you'll also need a qmp test for it.

Dave

> +        g_free(info);
> +    }
> +    hmp_handle_error(mon, &err);
> +}
> diff --git a/hmp.h b/hmp.h
> index d8b94ce9dc..c422aa2fac 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -143,5 +143,6 @@ void hmp_info_dump(Monitor *mon, const QDict *qdict);
>  void hmp_info_ramblock(Monitor *mon, const QDict *qdict);
>  void hmp_hotpluggable_cpus(Monitor *mon, const QDict *qdict);
>  void hmp_info_vm_generation_id(Monitor *mon, const QDict *qdict);
> +void hmp_info_memory(Monitor *mon, const QDict *qdict);
>  
>  #endif
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 4b50b652d3..33cd7cb3b8 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -4324,6 +4324,33 @@
>    'data': { 'name': 'str', '*migration-safe': 'bool', 'static': 'bool',
>              '*unavailable-features': [ 'str' ], 'typename': 'str' } }
>  
> +##
> +# @MemoryInfo:
> +#
> +# Memory information in bytes.
> +#
> +# @base-memory: size of static memory which was specified on Qemu start.
> +#
> +# @hot-plug-memory: size of hot-plugged memory.
> +#
> +# @ballooned-actual-memory: amount of guest memory available after ballooning.
> +#
> +# Since: 2.10.0
> +##
> +{ 'struct': 'MemoryInfo',
> +  'data'  : { 'base-memory': 'int', 'hot-plug-memory': 'int',
> +              'ballooned-actual-memory': 'int' } }
> +
> +##
> +# @query-memory:
> +#
> +# Return memory size information which includes
> +# static, hotplugged and ballooned memory.
> +#
> +# Since: 2.10.0
> +##
> +{ 'command': 'query-memory', 'returns': 'MemoryInfo' }
> +
>  ##
>  # @query-cpu-definitions:
>  #
> diff --git a/qmp.c b/qmp.c
> index 7ee9bcfdcf..7e57a9bbf9 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -712,3 +712,37 @@ ACPIOSTInfoList *qmp_query_acpi_ospm_status(Error **errp)
>  
>      return head;
>  }
> +
> +MemoryInfo *qmp_query_memory(Error **errp)
> +{
> +#ifdef CONFIG_MEM_HOTPLUG
> +    MemoryInfo *mem_info = g_malloc0(sizeof(MemoryInfo));
> +    BalloonInfo *balloon_info;
> +    Error *local_err = NULL;
> +
> +    mem_info->base_memory = ram_size;
> +    mem_info->hot_plug_memory = pc_existing_dimms_capacity(&local_err);
> +    if (local_err) {
> +        error_setg(errp, "could not get hot-plug memory info: %s",
> +                   error_get_pretty(local_err));
> +        g_free(mem_info);
> +        return NULL;
> +    }
> +
> +    /* In case if it is not possible to get balloon info, just ignore it. */
> +    balloon_info = qmp_query_balloon(&local_err);
> +    if (local_err) {
> +        mem_info->ballooned_actual_memory = 0;
> +        error_free(local_err);
> +    } else {
> +        mem_info->ballooned_actual_memory = balloon_info->actual;
> +    }
> +
> +    qapi_free_BalloonInfo(balloon_info);
> +
> +    return mem_info;
> +#else
> +    error_setg(errp, "command not supported for this configuration");
> +    return NULL;
> +#endif
> +}
> -- 
> 2.13.1.394.g41dd433
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK