src/share/vm/gc_implementation/g1/g1CodeCacheRemSet.hpp

Fri, 29 Aug 2014 13:12:21 +0200

author
mgerdin
date
Fri, 29 Aug 2014 13:12:21 +0200
changeset 7208
7baf47cb97cb
parent 6992
2c6ef90f030a
permissions
-rw-r--r--

8048268: G1 Code Root Migration performs poorly
Summary: Replace G1CodeRootSet with a Hashtable based implementation, merge Code Root Migration phase into Code Root Scanning
Reviewed-by: jmasa, brutisso, tschatzl

     1 /*
     2  * Copyright (c) 2014, 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_G1CODECACHEREMSET_HPP
    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1CODECACHEREMSET_HPP
    28 #include "memory/allocation.hpp"
    30 class CodeBlobClosure;
    31 class CodeRootSetTable;
    32 class HeapRegion;
    33 class nmethod;
    35 // Implements storage for a set of code roots.
    36 // All methods that modify the set are not thread-safe except if otherwise noted.
    37 class G1CodeRootSet VALUE_OBJ_CLASS_SPEC {
    38   friend class G1CodeRootSetTest;
    39  private:
    41   const static size_t SmallSize = 32;
    42   const static size_t Threshold = 24;
    43   const static size_t LargeSize = 512;
    45   CodeRootSetTable* _table;
    46   CodeRootSetTable* load_acquire_table();
    48   size_t _length;
    50   void move_to_large();
    51   void allocate_small_table();
    53  public:
    54   G1CodeRootSet() : _table(NULL), _length(0) {}
    55   ~G1CodeRootSet();
    57   static void purge();
    59   static size_t static_mem_size();
    61   void add(nmethod* method);
    63   bool remove(nmethod* method);
    65   // Safe to call without synchronization, but may return false negatives.
    66   bool contains(nmethod* method);
    68   void clear();
    70   void nmethods_do(CodeBlobClosure* blk) const;
    72   // Remove all nmethods which no longer contain pointers into our "owner" region
    73   void clean(HeapRegion* owner);
    75   bool is_empty() {
    76     bool empty = length() == 0;
    77     assert(empty == (_table == NULL), "is empty only if table is deallocated");
    78     return empty;
    79   }
    81   // Length in elements
    82   size_t length() const { return _length; }
    84   // Memory size in bytes taken by this set.
    85   size_t mem_size();
    87 };
    89 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1CODECACHEREMSET_HPP

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