Re: [Qemu-devel] [PATCH 4/5] Disable XBZRLE during migrate to file if it is active

[Orit Wasserman]

On 01/30/2013 01:07 PM, Paolo Bonzini wrote:
> 
>> On 01/30/2013 12:49 PM, Paolo Bonzini wrote:
>>>> XBZRLE is not effective when migrating to file.
>>>>
>>>> Disabling it automatically will remove the need to update the
>>>> command line to allow loading a guest from a file that was in
>>>> XBZRLE format.
>>>
>>> What about savevm?
>> I think a user that activate the XBZRLE capability before doing
>> savevm
>> can do that also before doing loadvm so I leave it up to him.
>> The problem with exec is that we load the file from command line and
>> than the user can't activate XBZRLE from the monitor or QMP.
>> So he gets an error at the moment.
> 
> Honest question: why do we need to activate XBZRLE at load time?
> The stream should just work, you do not need a cache do you?
true, I guess for sanity check ...
> 
> In other words, can you simply remove the "if" from
> 
>          } else if (flags & RAM_SAVE_FLAG_XBZRLE) {
> -            if (!migrate_use_xbzrle()) {
> -                return -EINVAL;
> -            }
Yes it will work and it is much a cleaner solution.
I will send a new version
>              void *host = host_from_stream_offset(f, addr, flags);
>              if (!host) {
>                  return -EINVAL;
>              }
>  
>              if (load_xbzrle(f, addr, host) < 0) {
>                  ret = -EINVAL;
>                  goto done;
>              }
> 
> ?
> 
> Paolo
>