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

Dmitry Samersoff dmitry.samersoff at oracle.com
Fri Sep 30 19:46:15 UTC 2016


My $.02

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

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++) {
  for (uint i = 0;
        i < (_small_block_max_size - _small_block_min_size);  ++i) {


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

Dmitry Samersoff
Oracle Java development team, Saint Petersburg, Russia
* I would love to change the world, but they won't give me the sources.

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