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src/share/vm/gc_implementation/g1/vm_operations_g1.hpp@e7d0505c8a30
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
1 /*
2 * Copyright (c) 2001, 2012, 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
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7 * published by the Free Software Foundation.
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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23 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP
28 #include "gc_implementation/g1/g1AllocationContext.hpp"
29 #include "gc_implementation/shared/vmGCOperations.hpp"
31 // VM_operations for the G1 collector.
32 // VM_GC_Operation:
33 // - VM_CGC_Operation
34 // - VM_G1CollectFull
35 // - VM_G1OperationWithAllocRequest
36 // - VM_G1CollectForAllocation
37 // - VM_G1IncCollectionPause
39 class VM_G1OperationWithAllocRequest: public VM_GC_Operation {
40 protected:
41 size_t _word_size;
42 HeapWord* _result;
43 bool _pause_succeeded;
44 AllocationContext_t _allocation_context;
46 public:
47 VM_G1OperationWithAllocRequest(unsigned int gc_count_before,
48 size_t word_size,
49 GCCause::Cause gc_cause)
50 : VM_GC_Operation(gc_count_before, gc_cause),
51 _word_size(word_size), _result(NULL), _pause_succeeded(false) { }
52 HeapWord* result() { return _result; }
53 bool pause_succeeded() { return _pause_succeeded; }
54 void set_allocation_context(AllocationContext_t context) { _allocation_context = context; }
55 AllocationContext_t allocation_context() { return _allocation_context; }
56 };
58 class VM_G1CollectFull: public VM_GC_Operation {
59 public:
60 VM_G1CollectFull(unsigned int gc_count_before,
61 unsigned int full_gc_count_before,
62 GCCause::Cause cause)
63 : VM_GC_Operation(gc_count_before, cause, full_gc_count_before) { }
64 virtual VMOp_Type type() const { return VMOp_G1CollectFull; }
65 virtual void doit();
66 virtual const char* name() const {
67 return "full garbage-first collection";
68 }
69 };
71 class VM_G1CollectForAllocation: public VM_G1OperationWithAllocRequest {
72 public:
73 VM_G1CollectForAllocation(unsigned int gc_count_before,
74 size_t word_size);
75 virtual VMOp_Type type() const { return VMOp_G1CollectForAllocation; }
76 virtual void doit();
77 virtual const char* name() const {
78 return "garbage-first collection to satisfy allocation";
79 }
80 };
82 class VM_G1IncCollectionPause: public VM_G1OperationWithAllocRequest {
83 private:
84 bool _should_initiate_conc_mark;
85 bool _should_retry_gc;
86 double _target_pause_time_ms;
87 unsigned int _old_marking_cycles_completed_before;
88 public:
89 VM_G1IncCollectionPause(unsigned int gc_count_before,
90 size_t word_size,
91 bool should_initiate_conc_mark,
92 double target_pause_time_ms,
93 GCCause::Cause gc_cause);
94 virtual VMOp_Type type() const { return VMOp_G1IncCollectionPause; }
95 virtual bool doit_prologue();
96 virtual void doit();
97 virtual void doit_epilogue();
98 virtual const char* name() const {
99 return "garbage-first incremental collection pause";
100 }
101 bool should_retry_gc() const { return _should_retry_gc; }
102 };
104 // Concurrent GC stop-the-world operations such as remark and cleanup;
105 // consider sharing these with CMS's counterparts.
106 class VM_CGC_Operation: public VM_Operation {
107 VoidClosure* _cl;
108 const char* _printGCMessage;
109 bool _needs_pll;
111 protected:
112 // java.lang.ref.Reference support
113 void acquire_pending_list_lock();
114 void release_and_notify_pending_list_lock();
116 public:
117 VM_CGC_Operation(VoidClosure* cl, const char *printGCMsg, bool needs_pll)
118 : _cl(cl), _printGCMessage(printGCMsg), _needs_pll(needs_pll) { }
119 virtual VMOp_Type type() const { return VMOp_CGC_Operation; }
120 virtual void doit();
121 virtual bool doit_prologue();
122 virtual void doit_epilogue();
123 virtual const char* name() const {
124 return "concurrent gc";
125 }
126 };
128 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_VM_OPERATIONS_G1_HPP
