Re: [Qemu-devel] [PATCH v2] migration: discard non-migratable RAMBlocks

[Cédric Le Goater]

On 04/20/2018 10:47 AM, Peter Maydell wrote:
> On 20 April 2018 at 07:59, Cédric Le Goater <address@hidden> wrote:
>> Hello David,
>>
>> On 04/19/2018 06:58 PM, Dr. David Alan Gilbert wrote:
>>> * Cédric Le Goater (address@hidden) wrote:
>>>> @@ -1823,6 +1831,7 @@ void qemu_ram_set_idstr(RAMBlock *new_block, const 
>>>> char *name, DeviceState *dev)
>>>>          }
>>>>      }
>>>>      pstrcat(new_block->idstr, sizeof(new_block->idstr), name);
>>>> +    new_block->flags |= RAM_MIGRATABLE;
>>>>
>>>>      rcu_read_lock();
>>>>      RAMBLOCK_FOREACH(block) {
>>>> @@ -1845,6 +1854,7 @@ void qemu_ram_unset_idstr(RAMBlock *block)
>>>>       */
>>>>      if (block) {
>>>>          memset(block->idstr, 0, sizeof(block->idstr));
>>>> +        block->flags &= ~RAM_MIGRATABLE;
>>>>      }
>>>>  }
>>>
>>> Why in qemu_ram_set_idstr and qemu_ram_(un)set_idstr ?  It seems an
>>> odd place to put them.
>>
>> The only place where this routines are called is from 
>> vmstate_un/register_ram()
>> It seemed unnecessary to add an extra interface qemu_ram_un/set_migratable().
> 
> Why not set the flags in vmstate_{register,unregister}_ram() ?

because the RAM flags are not exposed outside exec.c so it would 
require some qemu_ram_un/set_migratable() helpers like this is done
for RAM_UF_ZEROPAGE. That is possible of course. 

C.