view src/share/vm/memory/space.inline.hpp @ 12301:2c022e432e10

8024974: Incorrect use of GC_locker::is_active() Summary: SymbolTable and StringTable can make calls to GC_locker::is_active() outside a safepoint. This isn't safe because the GC_locker active state (lock count) is only updated at a safepoint and only remains valid as long as _needs_gc is true. However, outside a safepoint_needs_gc can change to false at any time, which makes it impossible to do a correct call to is_active() in that context. In this case these calls can just be removed since the input argument to basic_add() should never be on the heap and so there's no need to check the GC_locker state. This change also adjusts the assert() in is_active() to makes sure all calls to this function are always done under a safepoint. Reviewed-by: brutisso, dcubed Contributed-by: per.liden@oracle.com
author stefank
date Fri, 20 Sep 2013 10:53:28 +0200
parents b9a9ed0f8eeb
children c49dcaf78a65
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/*
 * Copyright (c) 2000, 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
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 */

#ifndef SHARE_VM_MEMORY_SPACE_INLINE_HPP
#define SHARE_VM_MEMORY_SPACE_INLINE_HPP

#include "gc_interface/collectedHeap.hpp"
#include "memory/space.hpp"
#include "memory/universe.hpp"
#include "runtime/safepoint.hpp"

inline HeapWord* Space::block_start(const void* p) {
  return block_start_const(p);
}

inline HeapWord* OffsetTableContigSpace::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* OffsetTableContigSpace::par_allocate(size_t size) {
  MutexLocker x(&_par_alloc_lock);
  // This ought to be just "allocate", because of the lock above, but that
  // ContiguousSpace::allocate asserts that either the allocating thread
  // holds the heap lock or it is the VM thread and we're at a safepoint.
  // The best I (dld) could figure was to put a field in ContiguousSpace
  // meaning "locking at safepoint taken care of", and set/reset that
  // here.  But this will do for now, especially in light of the comment
  // above.  Perhaps in the future some lock-free manner of keeping the
  // coordination.
  HeapWord* res = ContiguousSpace::par_allocate(size);
  if (res != NULL) {
    _offsets.alloc_block(res, size);
  }
  return res;
}

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

#endif // SHARE_VM_MEMORY_SPACE_INLINE_HPP