jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1MarkSweep.hpp@e7d0505c8a30

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

     1 /*

     2  * Copyright (c) 2001, 2013, 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_G1MARKSWEEP_HPP

    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1MARKSWEEP_HPP

    28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"

    29 #include "gc_implementation/g1/heapRegion.hpp"

    30 #include "memory/genMarkSweep.hpp"

    31 #include "memory/generation.hpp"

    32 #include "memory/universe.hpp"

    33 #include "oops/markOop.hpp"

    34 #include "oops/oop.hpp"

    35 #include "runtime/timer.hpp"

    36 #include "utilities/growableArray.hpp"

    38 class ReferenceProcessor;

    40 // G1MarkSweep takes care of global mark-compact garbage collection for a

    41 // G1CollectedHeap using a four-phase pointer forwarding algorithm.  All

    42 // generations are assumed to support marking; those that can also support

    43 // compaction.

    44 //

    45 // Class unloading will only occur when a full gc is invoked.

    46 class G1PrepareCompactClosure;

    48 class G1MarkSweep : AllStatic {

    49   friend class VM_G1MarkSweep;

    50   friend class Scavenge;

    52  public:

    54   static void invoke_at_safepoint(ReferenceProcessor* rp,

    55                                   bool clear_all_softrefs);

    57   static STWGCTimer* gc_timer() { return GenMarkSweep::_gc_timer; }

    58   static SerialOldTracer* gc_tracer() { return GenMarkSweep::_gc_tracer; }

    60  private:

    62   // Mark live objects

    63   static void mark_sweep_phase1(bool& marked_for_deopt,

    64                                 bool clear_all_softrefs);

    65   // Calculate new addresses

    66   static void mark_sweep_phase2();

    67   // Update pointers

    68   static void mark_sweep_phase3();

    69   // Move objects to new positions

    70   static void mark_sweep_phase4();

    72   static void allocate_stacks();

    73   static void prepare_compaction();

    74   static void prepare_compaction_work(G1PrepareCompactClosure* blk);

    75 };

    77 class G1PrepareCompactClosure : public HeapRegionClosure {

    78  protected:

    79   G1CollectedHeap* _g1h;

    80   ModRefBarrierSet* _mrbs;

    81   CompactPoint _cp;

    82   HeapRegionSetCount _humongous_regions_removed;

    84   virtual void prepare_for_compaction(HeapRegion* hr, HeapWord* end);

    85   void prepare_for_compaction_work(CompactPoint* cp, HeapRegion* hr, HeapWord* end);

    86   void free_humongous_region(HeapRegion* hr);

    87   bool is_cp_initialized() const { return _cp.space != NULL; }

    89  public:

    90   G1PrepareCompactClosure() :

    91     _g1h(G1CollectedHeap::heap()),

    92     _mrbs(_g1h->g1_barrier_set()),

    93     _humongous_regions_removed() { }

    95   void update_sets();

    96   bool doHeapRegion(HeapRegion* hr);

    97 };

    99 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1MARKSWEEP_HPP

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

src/share/vm/gc_implementation/g1/g1MarkSweep.hpp@e7d0505c8a30

src/share/vm/gc_implementation/g1/g1MarkSweep.hpp