RFR: 8202647: Add deduplicate_string function to CollectedHeap

[Stefan Karlsson]

On 2018-05-07 15:25, Robbin Ehn wrote:
> On 05/07/2018 03:12 PM, Stefan Karlsson wrote:
>> And here is the webrev:
>> http://cr.openjdk.java.net/~stefank/8202647/webrev.01/
> 
> Looks good, thanks for fixing.

Thanks, Robbin.

StefanK

> 
> /Robbin
> 
>>
>> StefanK
>>
>> On 2018-05-07 15:08, Stefan Karlsson wrote:
>>> Hi all,
>>>
>>> Please review this patch to add a CollectedHeap::deduplicate_string 
>>> virtual function.
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8202647
>>>
>>> Today we have this G1 specific code inside the StringTable:
>>>
>>> #if INCLUDE_G1GC
>>>   if (G1StringDedup::is_enabled()) {
>>>   // Deduplicate the string before it is interned. Note that we 
>>> should never
>>>   // deduplicate a string after it has been interned. Doing so will 
>>> counteract
>>>   // compiler optimizations done on e.g. interned string literals.
>>>   G1StringDedup::deduplicate(string());
>>>   }
>>> #endif
>>>
>>> This patch adds a new virtual call to CollectedHeap and hides the G1 
>>> specific code inside G1.
>>>
>>> I've verified that this doesn't cause any noticeable performance 
>>> regressions with one of Robbin's intern string JMH micro benchmarks 
>>> developed for JDK-8195097.
>>>
>>> Thanks,
>>> StefanK