Review Request: 8029921: CDS should allow user specify their own classlist

[Jiangli Zhou]

Hi,

Thanks very much for everyone's comments/inputs.

I have to say that I share the same view as Coleen on this. There are 
existing CDS related options, which are grouped into:

  -Xshare:<dump/auto/on/off>

and

  -XX: Shared* options

The -Xshare: options is to dump/disable/enable CDS archive, and the 
other options are more fine-grained control for CDS functionality. I 
would think the new classlist option fits into the second category, and 
it's better to not differ it from the rest of the -XX:shared* options.

There were questions raised as part of the discussion, such as will CDS 
support multiple archives. Those are still open-ended questions at this 
point, and we don't have a clear answer yet. At stage I think 
-XX:SharedClassListFile serves our current needs, which is to allow user 
specify their own classlist. A redesign of the CDS options can be done 
later when we have more clear picture of the new CDS functionality.

Thanks,
Jiangli


On 01/15/2014 07:54 PM, Ioi Lam wrote:
>
> On 1/15/14, 7:22 AM, Bob Vandette wrote:
>> On Jan 15, 2014, at 1:16 AM, David Holmes <David.Holmes at oracle.com> 
>> wrote:
>>
>>> Hi Jiangli,
>>>
>>> On 15/01/2014 3:19 AM, Jiangli Zhou wrote:
>>>> Hi David,
>>>>
>>>> Thanks for the suggestion. How does it work with the existing
>>>> -Xshare:dump/auto/on option? Is it possible to combine multiple
>>>> sub-options, so it would be something like 
>>>> -Xshare:dump,classlist=XXXX?
>>> Right - the classlist is only associated with dumping so some 
>>> modification to -Xshare:dump would be the way to do it. Exactly how 
>>> depends on what we think we may want to do in the future. For 
>>> example do we want to allow control over the name of the archive? If 
>>> so we might want something like:
>>>
>>> -Xshare:dump:in=xxx,out=yyy
>>>
>>> though I'm not sure of the best syntax/grammar to use for these kind 
>>> of compound options.
>>>
>>> At this stage we only want to define the class list file name so we 
>>> don't need to generalize too far, but we also want to choose a 
>>> syntax that doesn't preclude potential future changes.
>>>
>>> Comments from runtime folk (Hi Coleen!) would be appreciated. :)
>> Do we want the ability to select different archives at startup that 
>> have been dumped with different class lists?
>>
>> If so, then we'd need a way to specify the archive for -Xshare:on, ie 
>> -Xshare:on,archive=xxxx
>>
>> -Xshare:dump,list=xxx,archive=yyy
>> -Xshare:on,archive=yyy
>>
>> Otherwise if we don't want to support multiple archives, this option 
>> would be enough.
>>
>> -Xshare:dump,list=xxx
>>
>> Can we make the classlist easy to generate but either supporting  the 
>> -verbose:class output format or
>> by adding a new -verbose:classlist option, please?
>>
>>
> I am not fond of such comma-separated lists in general. They just make 
> the VM more complicated with a lot of parsing and syntax checks (which 
> come for free with the -XX options). They also make the user's life 
> more complicated. I.e., how would you quote space, comma and equal 
> signs, which may be part of file names?
>
> - Ioi
>