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Re: [Qemu-devel] [PATCH] hmp, qmp: introduce "info memory" and "query-me
From: |
David Hildenbrand |
Subject: |
Re: [Qemu-devel] [PATCH] hmp, qmp: introduce "info memory" and "query-memory" commands |
Date: |
Mon, 19 Jun 2017 09:47:51 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 |
On 13.06.2017 14:55, Vadim Galitsyn wrote:
> Commands above provide the following memory information in bytes:
Is the idea to have something like hmp_info_numa() ("info NUMA"), just
for qmp? And so it also works without NUMA?
I think, for this command to be helpful, you should include a per-NUMA
node information.
So what you could do:
- total_base memory
- total hotplugged memory
- base_memory per NUMA node
- hotplugged memory per NUMA node
>
> * hot-plug-memory - amount of memory that was hot-plugged.
>
We also have query-memory-devices for that already.
> * 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.
I don't think ballooning belongs into this at all.
>
> 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.
Can't you simply change query-balloon to show 0 in case no balloon is
around? Or why can't your caller simply deal with the fact that querying
the balloon might fail? Making a qmp interface directly copy the data
from another qmp interface looks strange.
>
> Signed-off-by: Vasilis Liaskovitis <address@hidden>
> Signed-off-by: Mohammed Gamal <address@hidden>
> Signed-off-by: Eduardo Otubo <address@hidden>
> Signed-off-by: Vadim Galitsyn <address@hidden>
> Reviewed-by: Eugene Crosser <address@hidden>
> Cc: Dr. David Alan Gilbert <address@hidden>
> Cc: Markus Armbruster <address@hidden>
> Cc: address@hidden
> ---
[...]
> +
> +MemoryInfo *qmp_query_memory(Error **errp)
> +{
> + 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);
This seems to be x86 specific.
Some machines (e.g. s390x) will not be properly accounted here.
(e.g. they round ram_size up/down) or don't use DIMMs. I think we should
query the machines instead.
> + 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;
> + }
--
Thanks,
David