RFR (M) 8164921: Memory leaked when instrumentation.retransformClasses() is called repeatedly

[Coleen Phillimore]

On 10/1/16 3:26 AM, Dmitry Samersoff wrote:
> Coleen,
>
>> Or something but the loops seem simple enough to me.
> OK. Thank you for explanation.

Thank you for you comments and for looking at the code.
Coleen
>
> -Dmitry
>
> On 2016-10-01 01:44, Coleen Phillimore wrote:
>>
>> On 9/30/16 3:46 PM, Dmitry Samersoff wrote:
>>> Coleen,
>>>
>>> My $.02
>>>
>>> 1.
>>> metaspace.cpp:279 we have assert(word_size >= _small_block_min_size,
>>> ...)  so at 868 and 895
>>> if (word_size < SmallBlocks::small_block_min_size()) {
>>> probably should be asserts as well
>>>
>>>
>>> 2.
>>> It might be better to rewrite loops at metaspace.cpp 261,268
>>>     for (uint i = _small_block_min_size; i < _small_block_max_size; i++) {
>>> as
>>>     for (uint i = 0;
>>>           i < (_small_block_max_size - _small_block_min_size);  ++i) {
>>> ...
>>      for (uint i = _small_block_min_size; i < _small_block_max_size; i++) {
>>        _small_lists[i - _small_block_min_size].set_size(i);
>>      }
>>
>>
>> In this loop I want 'i' to set the size.  The index of small_lists
>> starts at 0 but the size is the size of the blocks.  This might make
>> more sense like:
>>
>>      for (uint i = _small_block_min_size; i < _small_block_max_size; i++) {
>>        int k = i - _small_block_min_size;  // zero based addressing
>>        _small_lists[k].set_size(i);
>>      }
>>
>> Or something but the loops seem simple enough to me.
>>
>> Coleen
>>> -Dmitry
>>>
>>> On 2016-09-30 22:02, Coleen Phillimore wrote:
>>>> Summary: Return Metablocks smaller than dictionary's dark matter.
>>>>
>>>> This change contributed by Jon Masamitsu and myself.  To reclaim "dark
>>>> matter" this change adds an array of small blocks by size, created
>>>> lazily, to return Metablocks smaller than the BinaryTreeDictionary
>>>> entry's minimum size.   This change also fixed a bug in small object
>>>> double free and adds debugging code to check for this case.
>>>>
>>>> With this change, the submitted test case runs indefinitely.   Also
>>>> passed rbt tier 1-5 testing.
>>>>
>>>> open webrev at http://cr.openjdk.java.net/~coleenp/8164921.01/webrev
>>>> bug link https://bugs.openjdk.java.net/browse/JDK-8164921
>>>>
>>>> Thanks,
>>>> Coleen and Jon
>