view src/share/vm/gc_implementation/g1/heapRegion.inline.hpp @ 4912:a9647476d1a4

7132029: G1: mixed GC phase lasts for longer than it should Summary: Revamp of the mechanism that chooses old regions for inclusion in the CSet. It simplifies the code and introduces min and max bounds on the number of old regions added to the CSet at each mixed GC to avoid pathological cases. It also ensures that when we do a mixed GC we'll always find old regions to add to the CSet (i.e., it eliminates the case where a mixed GC will collect no old regions which can happen today). Reviewed-by: johnc, brutisso
author tonyp
date Wed, 15 Feb 2012 13:06:53 -0500
parents eff609af17d7
children 8a2e5a6a19a4
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/*
 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP

inline HeapWord* G1OffsetTableContigSpace::allocate(size_t size) {
  HeapWord* res = ContiguousSpace::allocate(size);
  if (res != NULL) {
    _offsets.alloc_block(res, size);
  }
  return res;
}

// Because of the requirement of keeping "_offsets" up to date with the
// allocations, we sequentialize these with a lock.  Therefore, best if
// this is used for larger LAB allocations only.
inline HeapWord* G1OffsetTableContigSpace::par_allocate(size_t size) {
  MutexLocker x(&_par_alloc_lock);
  // Given that we take the lock no need to use par_allocate() here.
  HeapWord* res = ContiguousSpace::allocate(size);
  if (res != NULL) {
    _offsets.alloc_block(res, size);
  }
  return res;
}

inline HeapWord* G1OffsetTableContigSpace::block_start(const void* p) {
  return _offsets.block_start(p);
}

inline HeapWord*
G1OffsetTableContigSpace::block_start_const(const void* p) const {
  return _offsets.block_start_const(p);
}

inline void HeapRegion::note_start_of_marking() {
  init_top_at_conc_mark_count();
  _next_marked_bytes = 0;
  _next_top_at_mark_start = top();
}

inline void HeapRegion::note_end_of_marking() {
  _prev_top_at_mark_start = _next_top_at_mark_start;
  _prev_marked_bytes = _next_marked_bytes;
  _next_marked_bytes = 0;

  assert(_prev_marked_bytes <=
         (size_t) pointer_delta(prev_top_at_mark_start(), bottom()) *
         HeapWordSize, "invariant");
}

inline void HeapRegion::note_start_of_copying(bool during_initial_mark) {
  if (is_survivor()) {
    // This is how we always allocate survivors.
    assert(_next_top_at_mark_start == bottom(), "invariant");
  } else {
    if (during_initial_mark) {
      // During initial-mark we'll explicitly mark any objects on old
      // regions that are pointed to by roots. Given that explicit
      // marks only make sense under NTAMS it'd be nice if we could
      // check that condition if we wanted to. Given that we don't
      // know where the top of this region will end up, we simply set
      // NTAMS to the end of the region so all marks will be below
      // NTAMS. We'll set it to the actual top when we retire this region.
      _next_top_at_mark_start = end();
    } else {
      // We could have re-used this old region as to-space over a
      // couple of GCs since the start of the concurrent marking
      // cycle. This means that [bottom,NTAMS) will contain objects
      // copied up to and including initial-mark and [NTAMS, top)
      // will contain objects copied during the concurrent marking cycle.
      assert(top() >= _next_top_at_mark_start, "invariant");
    }
  }
}

inline void HeapRegion::note_end_of_copying(bool during_initial_mark) {
  if (is_survivor()) {
    // This is how we always allocate survivors.
    assert(_next_top_at_mark_start == bottom(), "invariant");
  } else {
    if (during_initial_mark) {
      // See the comment for note_start_of_copying() for the details
      // on this.
      assert(_next_top_at_mark_start == end(), "pre-condition");
      _next_top_at_mark_start = top();
    } else {
      // See the comment for note_start_of_copying() for the details
      // on this.
      assert(top() >= _next_top_at_mark_start, "invariant");
    }
  }
}

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP