Review Request (S) 8005994: Method annotations are allocated unnecessarily during class file parsing

[Stefan Karlsson]

On 15 jan 2013, at 16:30, Coleen Phillimore <coleen.phillimore at oracle.com> wrote:

> 
> Stefan, This change looks good. 

Thanks.

>   How much footprint does this save?

For every class without annotations we save four arrays of size: 
 sizeof(Array<AnnotationArray*>) + (num_methods - 1) * sizeof(AnnotationArray*)

and we don't have to allocate the two Annotation objects and save:
 2 * sizeof(Annotations)

Do you want some real numbers from a benchmark?

thanks,
StefanK


> 
> On 01/15/2013 10:09 AM, Stefan Karlsson wrote:
>> On 01/15/2013 02:38 PM, Vitaly Davidovich wrote:
>>> Looks good Stefan. 
>> 
>> Thanks, Vitaly.
>> 
>>> The annotation creation code in classFileParser is really asking for a macro or helper function that does the checks and construction.
>>> 
>> 
>> I agree. Does anyone in the runtime team have any opinions on this?
> 
> Yes, I do.   The method annotations (and class ones too but not so much) are a problem for cleaning up metadata on class file parsing failure.  I am working on adding these to the inlined tables in ConstMethod, which is another messy area.
> 
> Coleen
> 
>> 
>> thanks,
>> StefanK
>> 
>>> Thanks
>>> 
>>> Sent from my phone
>>> 
>>> On Jan 15, 2013 7:27 AM, "Stefan Karlsson" <stefan.karlsson at oracle.com> wrote:
>>> http://cr.openjdk.java.net/~stefank/8005994/webrev.00/
>>> 
>>> HotSpot unnecessarily allocates annotations arrays when they are not needed. This memory regression was introduced when the annotation data structures were changed in the Permgen Removal project.
>>> 
>>> This fix:
>>> 1) reintroduces the old null checks
>>> 2) adds a null check before creating the newly introduced method type annotations.
>>> 3) adds a missing null check where the type annotations are used, since they now can be null.
>>> 
>>> Testing:
>>> jprt, jdk_lang and type annotations tests
>>> 
>>> thanks,
>>> StefanK
>> 
> 

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