jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp@e1162778c1c8 (annotated)

src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp@e1162778c1c8 (annotated)

src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp

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

author: johnc
date: Thu, 07 Apr 2011 09:53:20 -0700
changeset 2781: e1162778c1c8
parent 2314: f95d63e2154a
child 3156: f08d439fab8c
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
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  */
 #include "precompiled.hpp"
 #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
 #include "gc_implementation/g1/heapRegion.hpp"
 #include "gc_implementation/g1/satbQueue.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/thread.hpp"
 #ifdef TARGET_OS_FAMILY_linux
 # include "thread_linux.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_solaris
 # include "thread_solaris.inline.hpp"
 #endif
 #ifdef TARGET_OS_FAMILY_windows
 # include "thread_windows.inline.hpp"
 #endif
 G1SATBCardTableModRefBS::G1SATBCardTableModRefBS(MemRegion whole_heap,
                                                  int max_covered_regions) :
     CardTableModRefBSForCTRS(whole_heap, max_covered_regions)
 {
   _kind = G1SATBCT;
 }
 void G1SATBCardTableModRefBS::enqueue(oop pre_val) {
   // Nulls should have been already filtered.
   assert(pre_val->is_oop(true), "Error");
   if (!JavaThread::satb_mark_queue_set().is_active()) return;
   Thread* thr = Thread::current();
   if (thr->is_Java_thread()) {
     JavaThread* jt = (JavaThread*)thr;
     jt->satb_mark_queue().enqueue(pre_val);
   } else {
     MutexLocker x(Shared_SATB_Q_lock);
     JavaThread::satb_mark_queue_set().shared_satb_queue()->enqueue(pre_val);
   }
 }
 template <class T> void
 G1SATBCardTableModRefBS::write_ref_array_pre_work(T* dst, int count) {
   if (!JavaThread::satb_mark_queue_set().is_active()) return;
   T* elem_ptr = dst;
   for (int i = 0; i < count; i++, elem_ptr++) {
     T heap_oop = oopDesc::load_heap_oop(elem_ptr);
     if (!oopDesc::is_null(heap_oop)) {
       enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));
     }
   }
 }
 G1SATBCardTableLoggingModRefBS::
 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap,
                                int max_covered_regions) :
   G1SATBCardTableModRefBS(whole_heap, max_covered_regions),
   _dcqs(JavaThread::dirty_card_queue_set())
 {
   _kind = G1SATBCTLogging;
 }
 void
 G1SATBCardTableLoggingModRefBS::write_ref_field_work(void* field,
                                                      oop new_val) {
   jbyte* byte = byte_for(field);
   if (*byte != dirty_card) {
     *byte = dirty_card;
     Thread* thr = Thread::current();
     if (thr->is_Java_thread()) {
       JavaThread* jt = (JavaThread*)thr;
       jt->dirty_card_queue().enqueue(byte);
     } else {
       MutexLockerEx x(Shared_DirtyCardQ_lock,
                       Mutex::_no_safepoint_check_flag);
       _dcqs.shared_dirty_card_queue()->enqueue(byte);
     }
   }
 }
 void
 G1SATBCardTableLoggingModRefBS::write_ref_field_static(void* field,
                                                        oop new_val) {
   uintptr_t field_uint = (uintptr_t)field;
   uintptr_t new_val_uint = (uintptr_t)new_val;
   uintptr_t comb = field_uint ^ new_val_uint;
   comb = comb >> HeapRegion::LogOfHRGrainBytes;
   if (comb == 0) return;
   if (new_val == NULL) return;
   // Otherwise, log it.
   G1SATBCardTableLoggingModRefBS* g1_bs =
     (G1SATBCardTableLoggingModRefBS*)Universe::heap()->barrier_set();
   g1_bs->write_ref_field_work(field, new_val);
 }
 void
 G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr, bool whole_heap) {
   jbyte* byte = byte_for(mr.start());
   jbyte* last_byte = byte_for(mr.last());
   Thread* thr = Thread::current();
   if (whole_heap) {
     while (byte <= last_byte) {
       *byte = dirty_card;
       byte++;
     }
   } else {
     // Enqueue if necessary.
     if (thr->is_Java_thread()) {
       JavaThread* jt = (JavaThread*)thr;
       while (byte <= last_byte) {
         if (*byte != dirty_card) {
           *byte = dirty_card;
           jt->dirty_card_queue().enqueue(byte);
         }
         byte++;
       }
     } else {
       MutexLockerEx x(Shared_DirtyCardQ_lock,
                       Mutex::_no_safepoint_check_flag);
       while (byte <= last_byte) {
         if (*byte != dirty_card) {
           *byte = dirty_card;
           _dcqs.shared_dirty_card_queue()->enqueue(byte);
         }
         byte++;
       }
     }
   }
 }

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src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp@e1162778c1c8 (annotated)

src/share/vm/gc_implementation/g1/g1SATBCardTableModRefBS.cpp