Mon, 21 Oct 2013 18:51:37 +0200
8026851: Remove unnecessary code in GenRemSet
Summary: Removed the GenRemSet::rem_set_name() since we only have one remset.
Reviewed-by: stefank, mgerdin, tschatzl
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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_MEMORY_COLLECTORPOLICY_HPP
26 #define SHARE_VM_MEMORY_COLLECTORPOLICY_HPP
28 #include "memory/allocation.hpp"
29 #include "memory/barrierSet.hpp"
30 #include "memory/generationSpec.hpp"
31 #include "memory/genRemSet.hpp"
32 #include "utilities/macros.hpp"
34 // This class (or more correctly, subtypes of this class)
35 // are used to define global garbage collector attributes.
36 // This includes initialization of generations and any other
37 // shared resources they may need.
38 //
39 // In general, all flag adjustment and validation should be
40 // done in initialize_flags(), which is called prior to
41 // initialize_size_info().
42 //
43 // This class is not fully developed yet. As more collector(s)
44 // are added, it is expected that we will come across further
45 // behavior that requires global attention. The correct place
46 // to deal with those issues is this class.
48 // Forward declarations.
49 class GenCollectorPolicy;
50 class TwoGenerationCollectorPolicy;
51 class AdaptiveSizePolicy;
52 #if INCLUDE_ALL_GCS
53 class ConcurrentMarkSweepPolicy;
54 class G1CollectorPolicy;
55 #endif // INCLUDE_ALL_GCS
57 class GCPolicyCounters;
58 class MarkSweepPolicy;
60 class CollectorPolicy : public CHeapObj<mtGC> {
61 protected:
62 GCPolicyCounters* _gc_policy_counters;
64 // Requires that the concrete subclass sets the alignment constraints
65 // before calling.
66 virtual void initialize_flags();
67 virtual void initialize_size_info();
69 size_t _initial_heap_byte_size;
70 size_t _max_heap_byte_size;
71 size_t _min_heap_byte_size;
73 size_t _min_alignment;
74 size_t _max_alignment;
76 // The sizing of the heap are controlled by a sizing policy.
77 AdaptiveSizePolicy* _size_policy;
79 // Set to true when policy wants soft refs cleared.
80 // Reset to false by gc after it clears all soft refs.
81 bool _should_clear_all_soft_refs;
82 // Set to true by the GC if the just-completed gc cleared all
83 // softrefs. This is set to true whenever a gc clears all softrefs, and
84 // set to false each time gc returns to the mutator. For example, in the
85 // ParallelScavengeHeap case the latter would be done toward the end of
86 // mem_allocate() where it returns op.result()
87 bool _all_soft_refs_clear;
89 CollectorPolicy() :
90 _min_alignment(1),
91 _max_alignment(1),
92 _initial_heap_byte_size(0),
93 _max_heap_byte_size(0),
94 _min_heap_byte_size(0),
95 _size_policy(NULL),
96 _should_clear_all_soft_refs(false),
97 _all_soft_refs_clear(false)
98 {}
100 public:
101 // Return maximum heap alignment that may be imposed by the policy
102 static size_t compute_max_alignment();
104 size_t min_alignment() { return _min_alignment; }
105 size_t max_alignment() { return _max_alignment; }
107 size_t initial_heap_byte_size() { return _initial_heap_byte_size; }
108 size_t max_heap_byte_size() { return _max_heap_byte_size; }
109 size_t min_heap_byte_size() { return _min_heap_byte_size; }
111 enum Name {
112 CollectorPolicyKind,
113 TwoGenerationCollectorPolicyKind,
114 ConcurrentMarkSweepPolicyKind,
115 ASConcurrentMarkSweepPolicyKind,
116 G1CollectorPolicyKind
117 };
119 AdaptiveSizePolicy* size_policy() { return _size_policy; }
120 bool should_clear_all_soft_refs() { return _should_clear_all_soft_refs; }
121 void set_should_clear_all_soft_refs(bool v) { _should_clear_all_soft_refs = v; }
122 // Returns the current value of _should_clear_all_soft_refs.
123 // _should_clear_all_soft_refs is set to false as a side effect.
124 bool use_should_clear_all_soft_refs(bool v);
125 bool all_soft_refs_clear() { return _all_soft_refs_clear; }
126 void set_all_soft_refs_clear(bool v) { _all_soft_refs_clear = v; }
128 // Called by the GC after Soft Refs have been cleared to indicate
129 // that the request in _should_clear_all_soft_refs has been fulfilled.
130 void cleared_all_soft_refs();
132 // Identification methods.
133 virtual GenCollectorPolicy* as_generation_policy() { return NULL; }
134 virtual TwoGenerationCollectorPolicy* as_two_generation_policy() { return NULL; }
135 virtual MarkSweepPolicy* as_mark_sweep_policy() { return NULL; }
136 #if INCLUDE_ALL_GCS
137 virtual ConcurrentMarkSweepPolicy* as_concurrent_mark_sweep_policy() { return NULL; }
138 virtual G1CollectorPolicy* as_g1_policy() { return NULL; }
139 #endif // INCLUDE_ALL_GCS
140 // Note that these are not virtual.
141 bool is_generation_policy() { return as_generation_policy() != NULL; }
142 bool is_two_generation_policy() { return as_two_generation_policy() != NULL; }
143 bool is_mark_sweep_policy() { return as_mark_sweep_policy() != NULL; }
144 #if INCLUDE_ALL_GCS
145 bool is_concurrent_mark_sweep_policy() { return as_concurrent_mark_sweep_policy() != NULL; }
146 bool is_g1_policy() { return as_g1_policy() != NULL; }
147 #else // INCLUDE_ALL_GCS
148 bool is_concurrent_mark_sweep_policy() { return false; }
149 bool is_g1_policy() { return false; }
150 #endif // INCLUDE_ALL_GCS
153 virtual BarrierSet::Name barrier_set_name() = 0;
155 // Create the remembered set (to cover the given reserved region,
156 // allowing breaking up into at most "max_covered_regions").
157 virtual GenRemSet* create_rem_set(MemRegion reserved,
158 int max_covered_regions);
160 // This method controls how a collector satisfies a request
161 // for a block of memory. "gc_time_limit_was_exceeded" will
162 // be set to true if the adaptive size policy determine that
163 // an excessive amount of time is being spent doing collections
164 // and caused a NULL to be returned. If a NULL is not returned,
165 // "gc_time_limit_was_exceeded" has an undefined meaning.
166 virtual HeapWord* mem_allocate_work(size_t size,
167 bool is_tlab,
168 bool* gc_overhead_limit_was_exceeded) = 0;
170 // This method controls how a collector handles one or more
171 // of its generations being fully allocated.
172 virtual HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab) = 0;
173 // This method controls how a collector handles a metadata allocation
174 // failure.
175 virtual MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
176 size_t size,
177 Metaspace::MetadataType mdtype);
179 // Performace Counter support
180 GCPolicyCounters* counters() { return _gc_policy_counters; }
182 // Create the jstat counters for the GC policy. By default, policy's
183 // don't have associated counters, and we complain if this is invoked.
184 virtual void initialize_gc_policy_counters() {
185 ShouldNotReachHere();
186 }
188 virtual CollectorPolicy::Name kind() {
189 return CollectorPolicy::CollectorPolicyKind;
190 }
192 // Returns true if a collector has eden space with soft end.
193 virtual bool has_soft_ended_eden() {
194 return false;
195 }
197 };
199 class ClearedAllSoftRefs : public StackObj {
200 bool _clear_all_soft_refs;
201 CollectorPolicy* _collector_policy;
202 public:
203 ClearedAllSoftRefs(bool clear_all_soft_refs,
204 CollectorPolicy* collector_policy) :
205 _clear_all_soft_refs(clear_all_soft_refs),
206 _collector_policy(collector_policy) {}
208 ~ClearedAllSoftRefs() {
209 if (_clear_all_soft_refs) {
210 _collector_policy->cleared_all_soft_refs();
211 }
212 }
213 };
215 class GenCollectorPolicy : public CollectorPolicy {
216 protected:
217 size_t _min_gen0_size;
218 size_t _initial_gen0_size;
219 size_t _max_gen0_size;
221 GenerationSpec **_generations;
223 // Return true if an allocation should be attempted in the older
224 // generation if it fails in the younger generation. Return
225 // false, otherwise.
226 virtual bool should_try_older_generation_allocation(size_t word_size) const;
228 void initialize_flags();
229 void initialize_size_info();
231 // Try to allocate space by expanding the heap.
232 virtual HeapWord* expand_heap_and_allocate(size_t size, bool is_tlab);
234 // Scale the base_size by NewRation according to
235 // result = base_size / (NewRatio + 1)
236 // and align by min_alignment()
237 size_t scale_by_NewRatio_aligned(size_t base_size);
239 // Bound the value by the given maximum minus the
240 // min_alignment.
241 size_t bound_minus_alignment(size_t desired_size, size_t maximum_size);
243 public:
244 // Accessors
245 size_t min_gen0_size() { return _min_gen0_size; }
246 size_t initial_gen0_size() { return _initial_gen0_size; }
247 size_t max_gen0_size() { return _max_gen0_size; }
249 virtual int number_of_generations() = 0;
251 virtual GenerationSpec **generations() {
252 assert(_generations != NULL, "Sanity check");
253 return _generations;
254 }
256 virtual GenCollectorPolicy* as_generation_policy() { return this; }
258 virtual void initialize_generations() = 0;
260 virtual void initialize_all() {
261 initialize_flags();
262 initialize_size_info();
263 initialize_generations();
264 }
266 HeapWord* mem_allocate_work(size_t size,
267 bool is_tlab,
268 bool* gc_overhead_limit_was_exceeded);
270 HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab);
272 // Adaptive size policy
273 virtual void initialize_size_policy(size_t init_eden_size,
274 size_t init_promo_size,
275 size_t init_survivor_size);
276 };
278 // All of hotspot's current collectors are subtypes of this
279 // class. Currently, these collectors all use the same gen[0],
280 // but have different gen[1] types. If we add another subtype
281 // of CollectorPolicy, this class should be broken out into
282 // its own file.
284 class TwoGenerationCollectorPolicy : public GenCollectorPolicy {
285 protected:
286 size_t _min_gen1_size;
287 size_t _initial_gen1_size;
288 size_t _max_gen1_size;
290 void initialize_flags();
291 void initialize_size_info();
292 void initialize_generations() { ShouldNotReachHere(); }
294 public:
295 // Accessors
296 size_t min_gen1_size() { return _min_gen1_size; }
297 size_t initial_gen1_size() { return _initial_gen1_size; }
298 size_t max_gen1_size() { return _max_gen1_size; }
300 // Inherited methods
301 TwoGenerationCollectorPolicy* as_two_generation_policy() { return this; }
303 int number_of_generations() { return 2; }
304 BarrierSet::Name barrier_set_name() { return BarrierSet::CardTableModRef; }
306 virtual CollectorPolicy::Name kind() {
307 return CollectorPolicy::TwoGenerationCollectorPolicyKind;
308 }
310 // Returns true is gen0 sizes were adjusted
311 bool adjust_gen0_sizes(size_t* gen0_size_ptr, size_t* gen1_size_ptr,
312 const size_t heap_size, const size_t min_gen1_size);
313 };
315 class MarkSweepPolicy : public TwoGenerationCollectorPolicy {
316 protected:
317 void initialize_generations();
319 public:
320 MarkSweepPolicy();
322 MarkSweepPolicy* as_mark_sweep_policy() { return this; }
324 void initialize_gc_policy_counters();
325 };
327 #endif // SHARE_VM_MEMORY_COLLECTORPOLICY_HPP