Re: [Qemu-devel] [PATCH RFC v3 03/27] COLO: migrate colo related info to slave

[zhanghailiang <zhang.zhanghailiang@huawei.com>]

On 2015/2/17 7:20, Eric Blake wrote:
> On 02/11/2015 08:16 PM, zhanghailiang wrote:
>> We can know if we should go into COLO mode by the info that
>> has been migrated from PVM.
>>
>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>> Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
>> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
>> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
>> ---
>>   include/migration/migration-colo.h | 21 ++++++++++++++
>>   migration/Makefile.objs            |  1 +
>>   migration/colo-comm.c              | 56 ++++++++++++++++++++++++++++++++++++++
>>   vl.c                               |  5 +++-
>>   4 files changed, 82 insertions(+), 1 deletion(-)
>>   create mode 100644 include/migration/migration-colo.h
>>   create mode 100644 migration/colo-comm.c
>
>> +
>> +/* #define DEBUG_COLO */
>> +
>> +#ifdef DEBUG_COLO
>> +#define DPRINTF(fmt, ...) \
>> +    do { fprintf(stdout, "COLO: " fmt, ## __VA_ARGS__); } while (0)
>> +#else
>> +#define DPRINTF(fmt, ...) \
>> +    do { } while (0)
>> +#endif
>
> This is not very good (that is, it is a great way to write stale
> debugging statements that tend to bit-rot, and later fail to compile
> when you turn debug on).  Better is a usage pattern that enforces that
> the debug compiles but has no impact.  For example, see how block/ssh.c
> defines DPRINTF.
>

OK, will fix that in next version, thanks.