jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/vm_operations

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp

Fri, 10 Oct 2014 15:51:58 +0200

author: tschatzl
date: Fri, 10 Oct 2014 15:51:58 +0200
changeset 7257: e7d0505c8a30
parent 7118: 227a9e5e4b4a
child 7285: 1d6eb209432a
permissions: -rw-r--r--

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

 /*
  * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP
 #include "gc_implementation/g1/g1AllocationContext.hpp"
 #include "gc_implementation/shared/vmGCOperations.hpp"
 // VM_operations for the G1 collector.
 // VM_GC_Operation:
 //   - VM_CGC_Operation
 //   - VM_G1CollectFull
 //   - VM_G1OperationWithAllocRequest
 //     - VM_G1CollectForAllocation
 //     - VM_G1IncCollectionPause
 class VM_G1OperationWithAllocRequest: public VM_GC_Operation {
 protected:
   size_t    _word_size;
   HeapWord* _result;
   bool      _pause_succeeded;
   AllocationContext_t _allocation_context;
 public:
   VM_G1OperationWithAllocRequest(unsigned int gc_count_before,
                                  size_t       word_size,
                                  GCCause::Cause gc_cause)
     : VM_GC_Operation(gc_count_before, gc_cause),
       _word_size(word_size), _result(NULL), _pause_succeeded(false) { }
   HeapWord* result() { return _result; }
   bool pause_succeeded() { return _pause_succeeded; }
   void set_allocation_context(AllocationContext_t context) { _allocation_context = context; }
   AllocationContext_t  allocation_context() { return _allocation_context; }
 };
 class VM_G1CollectFull: public VM_GC_Operation {
 public:
   VM_G1CollectFull(unsigned int gc_count_before,
                    unsigned int full_gc_count_before,
                    GCCause::Cause cause)
     : VM_GC_Operation(gc_count_before, cause, full_gc_count_before) { }
   virtual VMOp_Type type() const { return VMOp_G1CollectFull; }
   virtual void doit();
   virtual const char* name() const {
     return "full garbage-first collection";
   }
 };
 class VM_G1CollectForAllocation: public VM_G1OperationWithAllocRequest {
 public:
   VM_G1CollectForAllocation(unsigned int gc_count_before,
                             size_t       word_size);
   virtual VMOp_Type type() const { return VMOp_G1CollectForAllocation; }
   virtual void doit();
   virtual const char* name() const {
     return "garbage-first collection to satisfy allocation";
   }
 };
 class VM_G1IncCollectionPause: public VM_G1OperationWithAllocRequest {
 private:
   bool         _should_initiate_conc_mark;
   bool         _should_retry_gc;
   double       _target_pause_time_ms;
   unsigned int _old_marking_cycles_completed_before;
 public:
   VM_G1IncCollectionPause(unsigned int   gc_count_before,
                           size_t         word_size,
                           bool           should_initiate_conc_mark,
                           double         target_pause_time_ms,
                           GCCause::Cause gc_cause);
   virtual VMOp_Type type() const { return VMOp_G1IncCollectionPause; }
   virtual bool doit_prologue();
   virtual void doit();
   virtual void doit_epilogue();
   virtual const char* name() const {
     return "garbage-first incremental collection pause";
   }
   bool should_retry_gc() const { return _should_retry_gc; }
 };
 // Concurrent GC stop-the-world operations such as remark and cleanup;
 // consider sharing these with CMS's counterparts.
 class VM_CGC_Operation: public VM_Operation {
   VoidClosure* _cl;
   const char* _printGCMessage;
   bool _needs_pll;
 protected:
   // java.lang.ref.Reference support
   void acquire_pending_list_lock();
   void release_and_notify_pending_list_lock();
 public:
   VM_CGC_Operation(VoidClosure* cl, const char *printGCMsg, bool needs_pll)
     : _cl(cl), _printGCMessage(printGCMsg), _needs_pll(needs_pll) { }
   virtual VMOp_Type type() const { return VMOp_CGC_Operation; }
   virtual void doit();
   virtual bool doit_prologue();
   virtual void doit_epilogue();
   virtual const char* name() const {
     return "concurrent gc";
   }
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/vm_operations_g1.hpp