7045330: G1: Simplify/fix the HeapRegionSeq class 7042285: G1: native memory leak during humongous object allocation 6804436: G1: heap region indices should be size_t Summary: A series of fixes and improvements to the HeapRegionSeq class: a) replace the _regions growable array with a standard C array, b) avoid de-allocating / re-allocating HeapRegion instances when the heap shrinks / grows (fix for 7042285), c) introduce fast method to map address to HeapRegion via a "biased" array pointer, d) embed the _hrs object in G1CollectedHeap, instead of pointing to it via an indirection, e) assume that all the regions added to the HeapRegionSeq instance are contiguous, f) replace int's with size_t's for indexes (and expand that to HeapRegion as part of 6804436), g) remove unnecessary / unused methods, h) rename a couple of fields (_alloc_search_start and _seq_bottom), i) fix iterate_from() not to always start from index 0 irrespective of the region passed to it, j) add a verification method to check the HeapRegionSeq assumptions, k) always call the wrappers for _hrs.iterate(), _hrs_length(), and _hrs.at() from G1CollectedHeap, not those methods directly, and l) unify the code that expands the sequence (by either re-using or creating a new HeapRegion) and make it robust wrt to a HeapRegion allocation failing. Reviewed-by: stefank, johnc, brutisso

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/*

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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_INLINE_HPP

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#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_INLINE_HPP

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#include "gc_implementation/g1/heapRegion.hpp"

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#include "gc_implementation/g1/heapRegionSeq.hpp"

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inline size_t HeapRegionSeq::addr_to_index_biased(HeapWord* addr) const {

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  assert(_heap_bottom <= addr && addr < _heap_end,

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         err_msg("addr: "PTR_FORMAT" bottom: "PTR_FORMAT" end: "PTR_FORMAT,

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                 addr, _heap_bottom, _heap_end));

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  size_t index = (size_t) addr >> _region_shift;

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  return index;

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}

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inline HeapRegion* HeapRegionSeq::addr_to_region_unsafe(HeapWord* addr) const {

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  assert(_heap_bottom <= addr && addr < _heap_end,

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         err_msg("addr: "PTR_FORMAT" bottom: "PTR_FORMAT" end: "PTR_FORMAT,

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                 addr, _heap_bottom, _heap_end));

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  size_t index_biased = addr_to_index_biased(addr);

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  HeapRegion* hr = _regions_biased[index_biased];

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  assert(hr != NULL, "invariant");

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  return hr;

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}

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inline HeapRegion* HeapRegionSeq::addr_to_region(HeapWord* addr) const {

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  if (addr != NULL && addr < _heap_end) {

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    assert(addr >= _heap_bottom,

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          err_msg("addr: "PTR_FORMAT" bottom: "PTR_FORMAT, addr, _heap_bottom));

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    return addr_to_region_unsafe(addr);

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  }

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  return NULL;

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}

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inline HeapRegion* HeapRegionSeq::at(size_t index) const {

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  assert(index < length(), "pre-condition");

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  HeapRegion* hr = _regions[index];

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  assert(hr != NULL, "sanity");

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  assert(hr->hrs_index() == index, "sanity");

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  return hr;

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}

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#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_INLINE_HPP