Re: [Xen-devel] [PATCH v9 09/25] tools/libx{l, c}: introduce should_checkpoint callback

[Wen Congyang <wency@xxxxxxxxxxxxxx>]

On 01/27/2016 05:09 AM, Konrad Rzeszutek Wilk wrote:
> On Tue, Jan 26, 2016 at 03:50:32PM -0500, Konrad Rzeszutek Wilk wrote:
>> On Wed, Dec 30, 2015 at 10:37:39AM +0800, Wen Congyang wrote:
>>> Under COLO, we are doing checkpoint on demand, if this
>>> callback returns 1, we will take another checkpoint.
>>
>> So 1 means OK.
>>
>>> 0 indicates unexpected error.
>>
>> Why not return an error?
>>>
>>> Signed-off-by: Yang Hongyang <hongyang.yang@xxxxxxxxxxxx>
>>> Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
>>> ---
>>>  tools/libxc/include/xenguest.h     | 18 ++++++++++++++++++
>>>  tools/libxl/libxl_save_msgs_gen.pl |  7 ++++---
>>>  2 files changed, 22 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/tools/libxc/include/xenguest.h b/tools/libxc/include/xenguest.h
>>> index bd133af..88d6e13 100644
>>> --- a/tools/libxc/include/xenguest.h
>>> +++ b/tools/libxc/include/xenguest.h
>>> @@ -62,6 +62,15 @@ struct save_callbacks {
>>>       * 1: take another checkpoint */
>>>      int (*checkpoint)(void* data);
>>>  
>>> +    /*
>>> +     * Called after the checkpoint callback.
>>> +     *
>>> +     * returns:
>>> +     * 0: terminate checkpointing gracefully
>>
>> checkpointing terminated gracefully
>>
>> Why not return -EXX instead ?
>>
>>> +     * 1: take another checkpoint
> 
> Also perhaps the function instead of 'should_checkpoint' should just be
> called 'checkpoint' or 'do_checkpoint' ?

I will check it. IIRC, should_checkpoint() only wait for a new checkpoint.
If so, I think we can call it wait_checkpoint().

Thanks
Wen Congyang

> 
> 
> .
> 




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