Re: [PATCH v2 14/16] migration/qapi: Introduce system-wise "remaining" reports

[Markus Armbruster <armbru@redhat.com>]

Peter Xu <peterx@redhat.com> writes:

> On Sat, Apr 25, 2026 at 07:46:45AM +0200, Markus Armbruster wrote:
>> Peter Xu <peterx@redhat.com> writes:

[...]

>> > The complete new version of patch is here (I updated quite a few places on
>> > the commit message):
>> >
>> > https://gitlab.com/peterx/qemu/-/commit/86d973360890cecc564a4a5bcf9a01b9efde368a
>> >
>> > Thanks,
>> 
>> I read the commit message.  No surprises except
>> 
>>     It should be the same value as RAM's remaining report when VFIO is not
>>     involved, and it should report more than that when VFIO is involved.
>> 
>>     One note is that this field will be an estimate and may not be sampled the
>>     exact same time versus the RAM remaining section.  So it may report
>>     slightly different values even if only RAM is involved.  The difference
>>     shouldn't matter though to mgmt to make correct decisions.
>> 
>> The second paragraph is new.  The first paragraph says they "should be
>> the same", the second that they "may [be] slightly different".
>> Suboptimal.
>
> Yes, it is misleading, I overlooked that. :(
>
>> 
>> Here's my try:
>> 
>>     It should be approximately the same value ...
>> 
>>     Only approximately, because this field will be ...
>> 
>> It's just a commit message, though.  Up to you.
>
> New version:
>
>     When VFIO is not involved, the value reported in the new field should
>     be approximately the same as reported in the "remaining" field of the
>     RAM section.  It is only an approximate value because the system-wide
>     remaining data is a cached value, which gets frequently updated by
>     migration core.  OTOH, the RAM's remaining data is accurate.
>     
>     When VFIO is involved, the new value reported should normally be
>     larger, because it will include the size of VFIO remaining data too.

Looks good to me, thanks!

>> QAPI schema
>> Acked-by: Markus Armbruster <armbru@redhat.com>
>
> Thanks, I will at least wait for 1-2 days if it still needs update.