RFR(XXS) 8190729: Adjustment to anonymous metadata space chunk allocation algorithm

[Zhengyu Gu]

Hi Coleen,

I fixed the style and generated committed webrev:

http://cr.openjdk.java.net/~zgu/8190729/webrev.02/

Thanks a lot!

-Zhengyu

On 11/27/2017 05:04 PM, coleen.phillimore at oracle.com wrote:
> 
> Hi, this is a bit bigger than XXS but it looks good to me.   Only one nit:
> 
> + if (_space_type == Metaspace::AnonymousMetaspaceType
> + && _mdtype == Metaspace::NonClassType
> + && sum_count_in_chunks_in_use(SpecializedIndex) < 
> _anon_metadata_specialize_chunk_limit
> + && word_size + Metachunk::overhead() <= SpecializedChunk) {
> + return SpecializedChunk;
> + }
> +
> 
> 
> I think the coding style is that the && are on the right hand side.   In 
> any case, I'll sponsor it for you.  Can you commit, and regenerate the 
> webrev with the commit message?   So I can use wget to get the patch.
> 
> thanks!
> Coleen
> 
> On 11/27/17 12:09 PM, Zhengyu Gu wrote:
>> Hi,
>>
>> To follow up recent discussion of anonymous metadata space memory 
>> usage, I would like submit this simple fix for review.
>>
>> By continuing allocating anonymous metadata space from SpecializeChunk 
>> pool, up to 4 chunks, it reduces the waste from 60+% to about 30%.
>>
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8190729
>> Webrev: http://cr.openjdk.java.net/~zgu/8190729/webrev.00/
>>
>> Test:
>>
>>   hotspot_tier1_runtime on Linux x64 (fastdebug and release)
>>
>>
>> Thanks,
>>
>> -Zhengyu
>