hotspot/src/share/vm/gc_implementation/g1/g1BlockOffsetTable.inline.hpp
author johnc
Thu, 09 May 2013 11:16:39 -0700
changeset 17327 4bd0581aa231
parent 14584 bd4290e6d0a5
child 24424 2658d7834c6e
permissions -rw-r--r--
7176479: G1: JVM crashes on T5-8 system with 1.5 TB heap Summary: Refactor G1's hot card cache and card counts table into their own files. Simplify the card counts table, including removing the encoding of the card index in each entry. The card counts table now has a 1:1 correspondence with the cards spanned by heap. Space for the card counts table is reserved from virtual memory (rather than C heap) during JVM startup and is committed/expanded when the heap is expanded. Changes were also reviewed-by Vitaly Davidovich. Reviewed-by: tschatzl, jmasa

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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP

#include "gc_implementation/g1/g1BlockOffsetTable.hpp"
#include "memory/space.hpp"

inline HeapWord* G1BlockOffsetTable::block_start(const void* addr) {
  if (addr >= _bottom && addr < _end) {
    return block_start_unsafe(addr);
  } else {
    return NULL;
  }
}

inline HeapWord*
G1BlockOffsetTable::block_start_const(const void* addr) const {
  if (addr >= _bottom && addr < _end) {
    return block_start_unsafe_const(addr);
  } else {
    return NULL;
  }
}

inline size_t G1BlockOffsetSharedArray::index_for(const void* p) const {
  char* pc = (char*)p;
  assert(pc >= (char*)_reserved.start() &&
         pc <  (char*)_reserved.end(),
         err_msg("p (" PTR_FORMAT ") not in reserved [" PTR_FORMAT ", " PTR_FORMAT ")",
                 p, (char*)_reserved.start(), (char*)_reserved.end()));
  size_t delta = pointer_delta(pc, _reserved.start(), sizeof(char));
  size_t result = delta >> LogN;
  check_index(result, "bad index from address");
  return result;
}

inline HeapWord*
G1BlockOffsetSharedArray::address_for_index(size_t index) const {
  check_index(index, "index out of range");
  HeapWord* result = _reserved.start() + (index << LogN_words);
  assert(result >= _reserved.start() && result < _reserved.end(),
         err_msg("bad address from index result " PTR_FORMAT
                 " _reserved.start() " PTR_FORMAT " _reserved.end() "
                 PTR_FORMAT,
                 result, _reserved.start(), _reserved.end()));
  return result;
}

inline HeapWord*
G1BlockOffsetArray::block_at_or_preceding(const void* addr,
                                          bool has_max_index,
                                          size_t max_index) const {
  assert(_array->offset_array(0) == 0, "objects can't cross covered areas");
  size_t index = _array->index_for(addr);
  // We must make sure that the offset table entry we use is valid.  If
  // "addr" is past the end, start at the last known one and go forward.
  if (has_max_index) {
    index = MIN2(index, max_index);
  }
  HeapWord* q = _array->address_for_index(index);

  uint offset = _array->offset_array(index);  // Extend u_char to uint.
  while (offset >= N_words) {
    // The excess of the offset from N_words indicates a power of Base
    // to go back by.
    size_t n_cards_back = BlockOffsetArray::entry_to_cards_back(offset);
    q -= (N_words * n_cards_back);
    assert(q >= _sp->bottom(), "Went below bottom!");
    index -= n_cards_back;
    offset = _array->offset_array(index);
  }
  assert(offset < N_words, "offset too large");
  q -= offset;
  return q;
}

inline HeapWord*
G1BlockOffsetArray::
forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n,
                                       const void* addr) const {
  if (csp() != NULL) {
    if (addr >= csp()->top()) return csp()->top();
    while (n <= addr) {
      q = n;
      oop obj = oop(q);
      if (obj->klass_or_null() == NULL) return q;
      n += obj->size();
    }
  } else {
    while (n <= addr) {
      q = n;
      oop obj = oop(q);
      if (obj->klass_or_null() == NULL) return q;
      n += _sp->block_size(q);
    }
  }
  assert(q <= n, "wrong order for q and addr");
  assert(addr < n, "wrong order for addr and n");
  return q;
}

inline HeapWord*
G1BlockOffsetArray::forward_to_block_containing_addr(HeapWord* q,
                                                     const void* addr) {
  if (oop(q)->klass_or_null() == NULL) return q;
  HeapWord* n = q + _sp->block_size(q);
  // In the normal case, where the query "addr" is a card boundary, and the
  // offset table chunks are the same size as cards, the block starting at
  // "q" will contain addr, so the test below will fail, and we'll fall
  // through quickly.
  if (n <= addr) {
    q = forward_to_block_containing_addr_slow(q, n, addr);
  }
  assert(q <= addr, "wrong order for current and arg");
  return q;
}

//////////////////////////////////////////////////////////////////////////
// BlockOffsetArrayNonContigSpace inlines
//////////////////////////////////////////////////////////////////////////
inline void G1BlockOffsetArray::freed(HeapWord* blk_start, HeapWord* blk_end) {
  // Verify that the BOT shows [blk_start, blk_end) to be one block.
  verify_single_block(blk_start, blk_end);
  // adjust _unallocated_block upward or downward
  // as appropriate
  if (BlockOffsetArrayUseUnallocatedBlock) {
    assert(_unallocated_block <= _end,
           "Inconsistent value for _unallocated_block");
    if (blk_end >= _unallocated_block && blk_start <= _unallocated_block) {
      // CMS-specific note: a block abutting _unallocated_block to
      // its left is being freed, a new block is being added or
      // we are resetting following a compaction
      _unallocated_block = blk_start;
    }
  }
}

inline void G1BlockOffsetArray::freed(HeapWord* blk, size_t size) {
  freed(blk, blk + size);
}

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_INLINE_HPP