jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/psPermGen.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 2001-2005 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 AdaptivePaddedAverage;

    27 class PSPermGen : public PSOldGen {

    28   friend class VMStructs;

    29  protected:

    30   AdaptivePaddedAverage* _avg_size;  // Used for sizing

    31   size_t _last_used;                 // Amount used at last GC, used for sizing

    33  public:

    34   // Initialize the generation.

    35   PSPermGen(ReservedSpace rs, size_t alignment, size_t initial_byte_size,

    36             size_t minimum_byte_size, size_t maximum_byte_size,

    37             const char* gen_name, int level);

    39   // Permanent Gen special allocation. Uses the OldGen allocation

    40   // routines, which should not be directly called on this generation.

    41   HeapWord* allocate_permanent(size_t word_size);

    43   // Size calculation.

    44   void compute_new_size(size_t used_before_collection);

    46   // MarkSweep code

    47   virtual void precompact();

    49   // Parallel old

    50   virtual void move_and_update(ParCompactionManager* cm);

    52   virtual const char* name() const { return "PSPermGen"; }

    53 };

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

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

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