Re: [PATCH 1/2] migration: Boost SaveStateEntry.instance_id to 64 bits

[Juan Quintela <quintela@redhat.com>]

"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:
> * Juan Quintela (quintela@redhat.com) wrote:
>> Peter Xu <peterx@redhat.com> wrote:
>> > It was "int" and used as 32bits fields (see save_section_header()).
>> > It's unsafe already because sizeof(int) could be 2 on i386, I think.
>> > So at least uint32_t would suite more.  While it also uses "-1" as a
>> > placeholder of "we want to generate the instance ID automatically".
>> > Hence a more proper value should be int64_t.
>> >
>> > This will start to be useful after next patch in which we can start to
>> > convert a real uint32_t value as instance ID.
>> >
>> > Signed-off-by: Peter Xu <peterx@redhat.com>
>> 
>> Hi
>> 
>> Being more helpful,  I think that it is better to just:
>> 
>> * change instance_id to be an uint32_t (notice that for all architectures
>>   that we support, it is actually int32_t).
>> 
>> * export calculate_new_instance_id() and adjust callers that use -1.
>> 
>> or
>> 
>> * export a new function that just use the calculate_new_instance_id()
>
> Do you mean that we end up with two functions, one that does it
> automatically, and one that takes an ID?

That is one option.

The other is that we export calculate_new_instance_id(), and we use that
instead of -1.

Later, Juan.