Re: [Qemu-devel] [PATCH v2 04/10] migration: detect compression and decompression errors

[Xiao Guangrong <guangrong.xiao@gmail.com>]

On 03/29/2018 12:25 PM, Peter Xu wrote:
> On Thu, Mar 29, 2018 at 11:51:03AM +0800, Xiao Guangrong wrote:
>>
>>
>> On 03/28/2018 05:59 PM, Peter Xu wrote:
>>> On Tue, Mar 27, 2018 at 05:10:37PM +0800, guangrong.xiao@gmail.com wrote:
>>>
>>> [...]
>>>
>>>> -static int compress_threads_load_setup(void)
>>>> +static int compress_threads_load_setup(QEMUFile *f)
>>>>    {
>>>>        int i, thread_count;
>>>> @@ -2665,6 +2685,7 @@ static int compress_threads_load_setup(void)
>>>>            }
>>>>            decomp_param[i].stream.opaque = &decomp_param[i];
>>>> +        decomp_param[i].file = f;
>>>
>>> On the source side the error will be set via:
>>>
>>>           qemu_file_set_error(migrate_get_current()->to_dst_file, blen);
>>>
>>> Maybe we can do similar things using migrate_incoming_get_current() to
>>> avoid caching the QEMUFile multiple times?
>>>
>>
>> I have considered it, however, it can not work as the @file used by ram
>> loader is not the file got from migrate_incoming_get_current() under some
>> cases.
>>
>> For example, in colo_process_incoming_thread(), the file passed to
>> qemu_loadvm_state() is a internal buffer and it is not easy to switch it
>> to incoming file.
> 
> I see. How about cache it in a global variable?  We have these
> already:
> 
>      thread_count = migrate_decompress_threads();
>      decompress_threads = g_new0(QemuThread, thread_count);
>      decomp_param = g_new0(DecompressParam, thread_count);
>      ...
> 
> IMHO we can add a new one too, at least we don't cache it multiple
> times (after all decomp_param[i]s are global variables too).
> 

Nice, that's good to me. Will add your Reviewed-by on this patch
as well if you do not mind. :)