6974928: G1: sometimes humongous objects are allocated in young regions Summary: as the title says, sometimes we are allocating humongous objects in young regions and we shouldn't. Reviewed-by: ysr, johnc

6959014: G1: assert(minimum_desired_capacity <= maximum_desired_capacity) failed: sanity check Summary: There are a few issues in the code that calculates whether to resize the heap and by how much: a) some calculations can overflow 32-bit size_t's, b) min_desired_capacity is not bounded by the max heap size, and c) the assrt that fires is in the wrong place. The fix also includes some tidying up of the related verbose code. Reviewed-by: ysr, jmasa

6948538: CMS: BOT walkers can fall into object allocation and initialization cracks Summary: GC workers now recognize an intermediate transient state of blocks which are allocated but have not yet completed initialization. blk_start() calls do not attempt to determine the size of a block in the transient state, rather waiting for the block to become initialized so that it is safe to query its size. Audited and ensured the order of initialization of object fields (klass, free bit and size) to respect block state transition protocol. Also included some new assertion checking code enabled in debug mode. Reviewed-by: chrisphi, johnc, poonam

6977952: Test: Sync missing tests from hs16.3 to hs17.x Reviewed-by: wrockett

Merge

Merge

6976378: ParNew: stats are printed unconditionally in debug builds Reviewed-by: tonyp

6973570: OrderAccess::storestore() scales poorly on multi-socket x64 and sparc: cache-line ping-ponging Summary: volatile store to static variable removed in favour of a volatile store to stack to avoid excessive cache coherency traffic; verified that the volatile store is not elided by any of our current compilers. Reviewed-by: dholmes, dice, jcoomes, kvn

6970376: ParNew: shared TaskQueue statistics Reviewed-by: ysr

6966222: G1: simplify TaskQueue overflow handling Reviewed-by: tonyp, ysr

6930581: G1: assert(ParallelGCThreads > 1 || n_yielded() == _hrrs->occupied(),"Should have yielded all the .. Summary: During RSet updating, when ParallelGCThreads is zero, references that point into the collection set are added directly the referenced region's RSet. This can cause the sparse table in the RSet to expand. RSet scanning and the "occupied" routine will then operate on different instances of the sparse table causing the assert to trip. This may also cause some cards added post expansion to be missed during RSet scanning. When ParallelGCThreads is non-zero such references are recorded on the "references to be scanned" queue and the card containing the reference is recorded in a dirty card queue for use in the event of an evacuation failure. Employ the parallel code in the serial case to avoid expanding the RSets of regions in the collection set. Reviewed-by: iveresov, ysr, tonyp

6963209: G1: remove the concept of abandoned pauses Summary: As part of 6944166 we disabled the concept of abandoned pauses (i.e., if the collection set is empty, we would still try to do a pause even if it is to update the RSets and scan the roots). This changeset removes the code and structures associated with abandoned pauses. Reviewed-by: iveresov, johnc

6962589: remove breadth first scanning code from parallel gc Summary: Remove the breadth-first copying order from ParallelScavenge and use depth-first by default. Reviewed-by: jcoomes, ysr, johnc

6814437: G1: remove the _new_refs array Summary: The per-worker _new_refs array is used to hold references that point into the collection set. It is populated during RSet updating and subsequently processed. In the event of an evacuation failure it processed again to recreate the RSets of regions in the collection set. Remove the per-worker _new_refs array by processing the references directly. Use a DirtyCardQueue to hold the cards containing the references so that the RSets of regions in the collection set can be recreated when handling an evacuation failure. Reviewed-by: iveresov, jmasa, tonyp