jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/vm_operations

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp@e1162778c1c8 (annotated)

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp

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

author: johnc
date: Thu, 07 Apr 2011 09:53:20 -0700
changeset 2781: e1162778c1c8
parent 2532: c798c277ddd1
child 3218: db89aa49298f
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_VM_OPERATIONS_G1_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP
 #include "gc_implementation/shared/vmGCOperations.hpp"
 // VM_operations for the G1 collector.
 // VM_GC_Operation:
 //   - VM_CGC_Operation
 //   - VM_G1CollectFull
 //   - VM_G1OperationWithAllocRequest
 //     - VM_G1CollectForAllocation
 //     - VM_G1IncCollectionPause
 class VM_G1OperationWithAllocRequest: public VM_GC_Operation {
 protected:
   size_t    _word_size;
   HeapWord* _result;
   bool      _pause_succeeded;
 public:
   VM_G1OperationWithAllocRequest(unsigned int gc_count_before,
                                  size_t       word_size)
     : VM_GC_Operation(gc_count_before, GCCause::_allocation_failure),
       _word_size(word_size), _result(NULL), _pause_succeeded(false) { }
   HeapWord* result() { return _result; }
   bool pause_succeeded() { return _pause_succeeded; }
 };
 class VM_G1CollectFull: public VM_GC_Operation {
 public:
   VM_G1CollectFull(unsigned int gc_count_before,
                    unsigned int full_gc_count_before,
                    GCCause::Cause cause)
     : VM_GC_Operation(gc_count_before, cause, full_gc_count_before) { }
   virtual VMOp_Type type() const { return VMOp_G1CollectFull; }
   virtual void doit();
   virtual const char* name() const {
     return "full garbage-first collection";
   }
 };
 class VM_G1CollectForAllocation: public VM_G1OperationWithAllocRequest {
 public:
   VM_G1CollectForAllocation(unsigned int gc_count_before,
                             size_t       word_size);
   virtual VMOp_Type type() const { return VMOp_G1CollectForAllocation; }
   virtual void doit();
   virtual const char* name() const {
     return "garbage-first collection to satisfy allocation";
   }
 };
 class VM_G1IncCollectionPause: public VM_G1OperationWithAllocRequest {
 private:
   bool         _should_initiate_conc_mark;
   double       _target_pause_time_ms;
   unsigned int _full_collections_completed_before;
 public:
   VM_G1IncCollectionPause(unsigned int   gc_count_before,
                           size_t         word_size,
                           bool           should_initiate_conc_mark,
                           double         target_pause_time_ms,
                           GCCause::Cause gc_cause);
   virtual VMOp_Type type() const { return VMOp_G1IncCollectionPause; }
   virtual void doit();
   virtual void doit_epilogue();
   virtual const char* name() const {
     return "garbage-first incremental collection pause";
   }
 };
 // Concurrent GC stop-the-world operations such as initial and final mark;
 // consider sharing these with CMS's counterparts.
 class VM_CGC_Operation: public VM_Operation {
   VoidClosure* _cl;
   const char* _printGCMessage;
 public:
   VM_CGC_Operation(VoidClosure* cl, const char *printGCMsg)
     : _cl(cl), _printGCMessage(printGCMsg) { }
   virtual VMOp_Type type() const { return VMOp_CGC_Operation; }
   virtual void doit();
   virtual bool doit_prologue();
   virtual void doit_epilogue();
   virtual const char* name() const {
     return "concurrent gc";
   }
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp@e1162778c1c8 (annotated)

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp