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

[Jiangli Zhou]

Hi David,

Please see comments below.

On 01/16/2014 08:23 PM, David Holmes wrote:
> On 17/01/2014 1:15 PM, Jiangli Zhou wrote:
>> 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.
>
> Did you see my response to that? The difference is the Xshare flags 
> control the CDS feature whereas the XX flags control details of the 
> implementation of CDS in hotspot.
>
> So is providing a custom class list a feature of CDS or just something 
> the hotspot implementation provides? I think it should be the former, 
> but initially can be the latter.

Yes, I saw your earlier response. It's a bit vague to me. Let's keep it 
as -XX:SharedClassListFile for now, as you also stated below.

Thanks,
Jiangli

>
>> 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.
>
> Yes let's simply stick with -XX:SharedClassListFile for now.
>
> David
> -----
>
>
>> 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
>>>
>>