src/share/vm/gc_implementation/g1/heapRegionSet.inline.hpp

Thu, 07 Apr 2011 09:53:20 -0700

author
johnc
date
Thu, 07 Apr 2011 09:53:20 -0700
changeset 2781
e1162778c1c8
parent 2714
455328d90876
child 3058
3be7439273c5
permissions
-rw-r--r--

7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes

     1 /*
     2  * copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
     4  *
     5  * This code is free software; you can redistribute it and/or modify it
     6  * under the terms of the GNU General Public License version 2 only, as
     7  * published by the Free Software Foundation.
     8  *
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    12  * version 2 for more details (a copy is included in the LICENSE file that
    13  * accompanied this code).
    14  *
    15  * You should have received a copy of the GNU General Public License version
    16  * 2 along with this work; if not, write to the Free Software Foundation,
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
    18  *
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
    20  * or visit www.oracle.com if you need additional information or have any
    21  * questions.
    22  *
    23  */
    25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_INLINE_HPP
    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_INLINE_HPP
    28 #include "gc_implementation/g1/heapRegionSet.hpp"
    30 //////////////////// HeapRegionSetBase ////////////////////
    32 inline void HeapRegionSetBase::update_for_addition(HeapRegion* hr) {
    33   // Assumes the caller has already verified the region.
    35   _length           += 1;
    36   if (!hr->isHumongous()) {
    37     _region_num     += 1;
    38   } else {
    39     _region_num     += calculate_region_num(hr);
    40   }
    41   _total_used_bytes += hr->used();
    42 }
    44 inline void HeapRegionSetBase::add_internal(HeapRegion* hr) {
    45   hrs_assert_region_ok(this, hr, NULL);
    46   assert(hr->next() == NULL, hrs_ext_msg(this, "should not already be linked"));
    48   update_for_addition(hr);
    49   hr->set_containing_set(this);
    50 }
    52 inline void HeapRegionSetBase::update_for_removal(HeapRegion* hr) {
    53   // Assumes the caller has already verified the region.
    54   assert(_length > 0, hrs_ext_msg(this, "pre-condition"));
    55   _length -= 1;
    57   size_t region_num_diff;
    58   if (!hr->isHumongous()) {
    59     region_num_diff = 1;
    60   } else {
    61     region_num_diff = calculate_region_num(hr);
    62   }
    63   assert(region_num_diff <= _region_num,
    64          hrs_err_msg("[%s] region's region num: "SIZE_FORMAT" "
    65                      "should be <= region num: "SIZE_FORMAT,
    66                      name(), region_num_diff, _region_num));
    67   _region_num -= region_num_diff;
    69   size_t used_bytes = hr->used();
    70   assert(used_bytes <= _total_used_bytes,
    71          hrs_err_msg("[%s] region's used bytes: "SIZE_FORMAT" "
    72                      "should be <= used bytes: "SIZE_FORMAT,
    73                      name(), used_bytes, _total_used_bytes));
    74   _total_used_bytes -= used_bytes;
    75 }
    77 inline void HeapRegionSetBase::remove_internal(HeapRegion* hr) {
    78   hrs_assert_region_ok(this, hr, this);
    79   assert(hr->next() == NULL, hrs_ext_msg(this, "should already be unlinked"));
    81   hr->set_containing_set(NULL);
    82   update_for_removal(hr);
    83 }
    85 //////////////////// HeapRegionSet ////////////////////
    87 inline void HeapRegionSet::add(HeapRegion* hr) {
    88   hrs_assert_mt_safety_ok(this);
    89   // add_internal() will verify the region.
    90   add_internal(hr);
    91 }
    93 inline void HeapRegionSet::remove(HeapRegion* hr) {
    94   hrs_assert_mt_safety_ok(this);
    95   // remove_internal() will verify the region.
    96   remove_internal(hr);
    97 }
    99 inline void HeapRegionSet::remove_with_proxy(HeapRegion* hr,
   100                                              HeapRegionSet* proxy_set) {
   101   // No need to fo the MT safety check here given that this method
   102   // does not update the contents of the set but instead accumulates
   103   // the changes in proxy_set which is assumed to be thread-local.
   104   hrs_assert_sets_match(this, proxy_set);
   105   hrs_assert_region_ok(this, hr, this);
   107   hr->set_containing_set(NULL);
   108   proxy_set->update_for_addition(hr);
   109 }
   111 //////////////////// HeapRegionLinkedList ////////////////////
   113 inline void HeapRegionLinkedList::add_as_head(HeapRegion* hr) {
   114   hrs_assert_mt_safety_ok(this);
   115   assert((length() == 0 && _head == NULL && _tail == NULL) ||
   116          (length() >  0 && _head != NULL && _tail != NULL),
   117          hrs_ext_msg(this, "invariant"));
   118   // add_internal() will verify the region.
   119   add_internal(hr);
   121   // Now link the region.
   122   if (_head != NULL) {
   123     hr->set_next(_head);
   124   } else {
   125     _tail = hr;
   126   }
   127   _head = hr;
   128 }
   130 inline void HeapRegionLinkedList::add_as_tail(HeapRegion* hr) {
   131   hrs_assert_mt_safety_ok(this);
   132   assert((length() == 0 && _head == NULL && _tail == NULL) ||
   133          (length() >  0 && _head != NULL && _tail != NULL),
   134          hrs_ext_msg(this, "invariant"));
   135   // add_internal() will verify the region.
   136   add_internal(hr);
   138   // Now link the region.
   139   if (_tail != NULL) {
   140     _tail->set_next(hr);
   141   } else {
   142     _head = hr;
   143   }
   144   _tail = hr;
   145 }
   147 inline HeapRegion* HeapRegionLinkedList::remove_head() {
   148   hrs_assert_mt_safety_ok(this);
   149   assert(!is_empty(), hrs_ext_msg(this, "the list should not be empty"));
   150   assert(length() > 0 && _head != NULL && _tail != NULL,
   151          hrs_ext_msg(this, "invariant"));
   153   // We need to unlink it first.
   154   HeapRegion* hr = _head;
   155   _head = hr->next();
   156   if (_head == NULL) {
   157     _tail = NULL;
   158   }
   159   hr->set_next(NULL);
   161   // remove_internal() will verify the region.
   162   remove_internal(hr);
   163   return hr;
   164 }
   166 inline HeapRegion* HeapRegionLinkedList::remove_head_or_null() {
   167   hrs_assert_mt_safety_ok(this);
   169   if (!is_empty()) {
   170     return remove_head();
   171   } else {
   172     return NULL;
   173   }
   174 }
   176 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_INLINE_HPP

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