Hi Sascha,
On 06/02/2016 08:01 AM, Sascha Silbe wrote:
> Dear Jianjun,
>
> Jianjun Duan <du...@linux.vnet.ibm.com> writes:
>
> [include/migration/vmstate.h]
>> @@ -185,6 +185,8 @@ enum VMStateFlags {
>> * to determine the number of entries in the array. Only valid in
>> * combination with one of VMS_VARRAY*. */
>> VMS_MULTIPLY_ELEMENTS = 0x4000,
>> + /* For fields which need customized handling, such as QTAILQ in
>> queue.h*/
>> + VMS_CSTM = 0x8000,
>
> Can you describe (in the comment) how this customised handling is
> performed, please? I.e. describe what exactly happens if the flag is
> set, from the point of view of an API consumer.
I will add more comments. When this flag is set VMStateInfo.get/put will
be used in vmstate_load/save_state instead of recursive call. And the
user should implement VMStateInfo.get/put to handle the concerned data
structure.
> Also, why do you need this flag at all? The only change I can see is
> that you pass additional information to VMStateInfo.get() / .put(),
> using NULL if it's not set. Why don't you just always pass the
> additional information? If the additional information is not needed by
> get() / put() the parameter will be unused anyway.
You can do it without creating this flag. Instead just to check if info
is set in the field. However I think it is more readable and more robust
to check this flag in vmstate_load/get_state.
> Sascha
>
Thanks,
Jianjun
