jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/asPSYoungGen.hpp@1fdb98a17101

6716785: implicit null checks not triggering with CompressedOops
Summary: allocate alignment-sized page(s) below java heap so that memory accesses at heap_base+1page give signal and cause an implicit null check
Reviewed-by: kvn, jmasa, phh, jcoomes

     1 /*

     2  * Copyright 2003 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    25 class ASPSYoungGen : public PSYoungGen {

    26   friend class VMStructs;

    27  private:

    28   size_t _gen_size_limit;

    29  protected:

    30   virtual size_t available_to_live();

    32  public:

    33   ASPSYoungGen(size_t         initial_byte_size,

    34                size_t         minimum_byte_size,

    35                size_t         byte_size_limit);

    37   ASPSYoungGen(PSVirtualSpace* vs,

    38                size_t         initial_byte_size,

    39                size_t         minimum_byte_size,

    40                size_t         byte_size_limit);

    42   void initialize(ReservedSpace rs, size_t alignment);

    43   void initialize_virtual_space(ReservedSpace rs, size_t alignment);

    45   size_t gen_size_limit() { return _gen_size_limit; }

    46   void set_gen_size_limit(size_t v) { _gen_size_limit = v; }

    48   bool resize_generation(size_t eden_size, size_t survivor_size);

    49   void resize_spaces(size_t eden_size, size_t survivor_size);

    51   // Adjust eden to be consistent with the virtual space.

    52   void reset_after_change();

    54   // Adaptive size policy support

    55   // Return number of bytes that the generation can expand/contract.

    56   size_t available_for_expansion();

    57   size_t available_for_contraction();

    59   // Accessors

    60   void set_reserved(MemRegion v) { _reserved = v; }

    62   // Printing support

    63   virtual const char* short_name() const { return "ASPSYoungGen"; }

    64 };

Mercurial > jdk8-mips64-public > hotspot / file revision

src/share/vm/gc_implementation/parallelScavenge/asPSYoungGen.hpp@1fdb98a17101

src/share/vm/gc_implementation/parallelScavenge/asPSYoungGen.hpp