jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp@e1162778c1c8 (annotated)

src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp@e1162778c1c8 (annotated)

src/share/vm/gc_implementation/g1/g1CollectedHeap.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 2715: abdfc822206f
child 2963: c3f1170908be
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

 /*
  * Copyright (c) 2001, 2011, 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_G1COLLECTEDHEAP_INLINE_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_INLINE_HPP
 #include "gc_implementation/g1/concurrentMark.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.hpp"
 #include "gc_implementation/g1/g1AllocRegion.inline.hpp"
 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
 #include "utilities/taskqueue.hpp"
 // Inline functions for G1CollectedHeap
 inline HeapRegion*
 G1CollectedHeap::heap_region_containing(const void* addr) const {
   HeapRegion* hr = _hrs->addr_to_region(addr);
   // hr can be null if addr in perm_gen
   if (hr != NULL && hr->continuesHumongous()) {
     hr = hr->humongous_start_region();
   }
   return hr;
 }
 inline HeapRegion*
 G1CollectedHeap::heap_region_containing_raw(const void* addr) const {
   assert(_g1_reserved.contains(addr), "invariant");
   size_t index = pointer_delta(addr, _g1_reserved.start(), 1)
                                         >> HeapRegion::LogOfHRGrainBytes;
   HeapRegion* res = _hrs->at(index);
   assert(res == _hrs->addr_to_region(addr), "sanity");
   return res;
 }
 inline bool G1CollectedHeap::obj_in_cs(oop obj) {
   HeapRegion* r = _hrs->addr_to_region(obj);
   return r != NULL && r->in_collection_set();
 }
 inline HeapWord*
 G1CollectedHeap::attempt_allocation(size_t word_size,
                                     unsigned int* gc_count_before_ret) {
   assert_heap_not_locked_and_not_at_safepoint();
   assert(!isHumongous(word_size), "attempt_allocation() should not "
          "be called for humongous allocation requests");
   HeapWord* result = _mutator_alloc_region.attempt_allocation(word_size,
                                                       false /* bot_updates */);
   if (result == NULL) {
     result = attempt_allocation_slow(word_size, gc_count_before_ret);
   }
   assert_heap_not_locked();
   if (result != NULL) {
     dirty_young_block(result, word_size);
   }
   return result;
 }
 // It dirties the cards that cover the block so that so that the post
 // write barrier never queues anything when updating objects on this
 // block. It is assumed (and in fact we assert) that the block
 // belongs to a young region.
 inline void
 G1CollectedHeap::dirty_young_block(HeapWord* start, size_t word_size) {
   assert_heap_not_locked();
   // Assign the containing region to containing_hr so that we don't
   // have to keep calling heap_region_containing_raw() in the
   // asserts below.
   DEBUG_ONLY(HeapRegion* containing_hr = heap_region_containing_raw(start);)
   assert(containing_hr != NULL && start != NULL && word_size > 0,
          "pre-condition");
   assert(containing_hr->is_in(start), "it should contain start");
   assert(containing_hr->is_young(), "it should be young");
   assert(!containing_hr->isHumongous(), "it should not be humongous");
   HeapWord* end = start + word_size;
   assert(containing_hr->is_in(end - 1), "it should also contain end - 1");
   MemRegion mr(start, end);
   ((CardTableModRefBS*)_g1h->barrier_set())->dirty(mr);
 }
 inline RefToScanQueue* G1CollectedHeap::task_queue(int i) const {
   return _task_queues->queue(i);
 }
 inline  bool G1CollectedHeap::isMarkedPrev(oop obj) const {
   return _cm->prevMarkBitMap()->isMarked((HeapWord *)obj);
 }
 inline bool G1CollectedHeap::isMarkedNext(oop obj) const {
   return _cm->nextMarkBitMap()->isMarked((HeapWord *)obj);
 }
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_INLINE_HPP

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src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp@e1162778c1c8 (annotated)

src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp