RFR(XXS) 8187629: NMT: Memory miscounting in compiler (C2)

[Zhengyu Gu]

Hi Vladimir,


On 09/19/2017 12:14 PM, Vladimir Kozlov wrote:
> Compilers also use a lot thread local ResourceArea - 
> Thread::current()->resource_area() and NEW_RESOURCE_ARRAY() macro.
> But thread local area is defined as mtThread:
> 
> http://hg.openjdk.java.net/jdk10/hs/hotspot/file/5ab7a67bc155/src/share/vm/runtime/thread.cpp#l218 

Thread's resource area is general purpose per-thread storage and used by 
many subsystems. Unfortunately, NMT has no way to distinguish the users 
at this moment, categorizing as mThread is sort of placeholder.

I am welcome to any suggestions

Thanks,

-Zhengyu


> 
> 
> Vladimir
> 
> On 9/18/17 12:17 PM, Zhengyu Gu wrote:
>> Compiler (C2) uses ResourceArea instead of Arena in some 
>> circumstances, so it can take advantage of ResourceMark. However, 
>> ResourceArea is tagged as mtThread, that results those memory is 
>> miscounted by NMT
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8187629
>> Webrev: http://cr.openjdk.java.net/~zgu/8187629/webrev.00/
>>
>>
>> Test:
>>
>>    hotspot_tier1 (fastdebug and release) on Linux x64
>>
>>
>> Thanks,
>>
>> -Zhengyu