jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1ConcurrentMarkObjArrayProcessor.hpp@8c95980d0b66

     1 /*

     2  * Copyright (c) 2016, 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_G1_G1CONCURRENTMARKOBJARRAYPROCESSOR_HPP

    26 #define SHARE_VM_GC_G1_G1CONCURRENTMARKOBJARRAYPROCESSOR_HPP

    28 #include "oops/oopsHierarchy.hpp"

    29 #include "memory/allocation.hpp"

    31 class CMTask;

    33 // Helper class to mark through large objArrays during marking in an efficient way.

    34 // Instead of pushing large object arrays, we push continuations onto the

    35 // mark stack. These continuations are identified by having their LSB set.

    36 // This allows incremental processing of large objects.

    37 class G1CMObjArrayProcessor VALUE_OBJ_CLASS_SPEC {

    38 private:

    39   // The bit mask for the continuation indicator of elements on the mark stack.

    40   static const size_t ArraySliceBit = 1;

    42   // Reference to the task for doing the actual work.

    43   CMTask* _task;

    45   // Encodes the given address as a continuation "oop".

    46   oop encode_array_slice(HeapWord* addr);

    47   // Remove the continuation marker from the given oop from the mark stack.

    48   HeapWord* decode_array_slice(oop value);

    50   // Push the continuation at the given address onto the mark stack.

    51   void push_array_slice(HeapWord* addr);

    53   // Process (apply the closure) on the given continuation of the given objArray.

    54   size_t process_array_slice(objArrayOop const obj, HeapWord* start_from, size_t remaining);

    55 public:

    56   static bool is_array_slice(void* obj) { return ((uintptr_t)obj & ArraySliceBit) != 0; }

    58   static bool should_be_sliced(oop obj);

    60   G1CMObjArrayProcessor(CMTask* task) : _task(task) {

    61   }

    63   // Process the given continuation "oop". Returns the number of words scanned.

    64   size_t process_slice(oop obj);

    65   // Start processing the given objArrayOop by scanning the header and pushing its

    66   // continuation.

    67   size_t process_obj(oop obj);

    68 };

    70 #endif /* SHARE_VM_GC_G1_G1CONCURRENTMARKOBJARRAYPROCESSOR_HPP */

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