Mercurial > hg > truffle
comparison src/share/vm/gc_implementation/g1/heapRegionSet.hpp @ 2152:0fa27f37d4d4
6977804: G1: remove the zero-filling thread
Summary: This changeset removes the zero-filling thread from G1 and collapses the two free region lists we had before (the "free" and "unclean" lists) into one. The new free list uses the new heap region sets / lists abstractions that we'll ultimately use it to keep track of all regions in the heap. A heap region set was also introduced for the humongous regions. Finally, this change increases the concurrency between the thread that completes freeing regions (after a cleanup pause) and the rest of the system (before we'd have to wait for said thread to complete before allocating a new region). The changest also includes a lot of refactoring and code simplification.
Reviewed-by: jcoomes, johnc
author | tonyp |
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date | Wed, 19 Jan 2011 19:30:42 -0500 |
parents | |
children | 1216415d8e35 |
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1 /* | |
2 * copyright (c) 2011, 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 */ | |
24 | |
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP | |
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP | |
27 | |
28 #include "gc_implementation/g1/heapRegion.hpp" | |
29 | |
30 // Large buffer for some cases where the output might be larger than normal. | |
31 #define HRL_ERR_MSG_BUFSZ 512 | |
32 typedef FormatBuffer<HRL_ERR_MSG_BUFSZ> hrl_err_msg; | |
33 | |
34 // Set verification will be forced either if someone defines | |
35 // HEAP_REGION_SET_FORCE_VERIFY to be 1, or in builds in which | |
36 // asserts are compiled in. | |
37 #ifndef HEAP_REGION_SET_FORCE_VERIFY | |
38 #define HEAP_REGION_SET_FORCE_VERIFY defined(ASSERT) | |
39 #endif // HEAP_REGION_SET_FORCE_VERIFY | |
40 | |
41 //////////////////// HeapRegionSetBase //////////////////// | |
42 | |
43 // Base class for all the classes that represent heap region sets. It | |
44 // contains the basic attributes that each set needs to maintain | |
45 // (e.g., length, region num, used bytes sum) plus any shared | |
46 // functionality (e.g., verification). | |
47 | |
48 class hrl_ext_msg; | |
49 | |
50 class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC { | |
51 friend class hrl_ext_msg; | |
52 | |
53 protected: | |
54 static size_t calculate_region_num(HeapRegion* hr); | |
55 | |
56 static size_t _unrealistically_long_length; | |
57 | |
58 // The number of regions added to the set. If the set contains | |
59 // only humongous regions, this reflects only 'starts humongous' | |
60 // regions and does not include 'continues humongous' ones. | |
61 size_t _length; | |
62 | |
63 // The total number of regions represented by the set. If the set | |
64 // does not contain humongous regions, this should be the same as | |
65 // _length. If the set contains only humongous regions, this will | |
66 // include the 'continues humongous' regions. | |
67 size_t _region_num; | |
68 | |
69 // We don't keep track of the total capacity explicitly, we instead | |
70 // recalculate it based on _region_num and the heap region size. | |
71 | |
72 // The sum of used bytes in the all the regions in the set. | |
73 size_t _total_used_bytes; | |
74 | |
75 const char* _name; | |
76 | |
77 bool _verify_in_progress; | |
78 size_t _calc_length; | |
79 size_t _calc_region_num; | |
80 size_t _calc_total_capacity_bytes; | |
81 size_t _calc_total_used_bytes; | |
82 | |
83 // verify_region() is used to ensure that the contents of a region | |
84 // added to / removed from a set are consistent. Different sets | |
85 // make different assumptions about the regions added to them. So | |
86 // each set can override verify_region_extra(), which is called | |
87 // from verify_region(), and do any extra verification it needs to | |
88 // perform in that. | |
89 virtual const char* verify_region_extra(HeapRegion* hr) { return NULL; } | |
90 bool verify_region(HeapRegion* hr, | |
91 HeapRegionSetBase* expected_containing_set); | |
92 | |
93 // Indicates whether all regions in the set should be humongous or | |
94 // not. Only used during verification. | |
95 virtual bool regions_humongous() = 0; | |
96 | |
97 // Indicates whether all regions in the set should be empty or | |
98 // not. Only used during verification. | |
99 virtual bool regions_empty() = 0; | |
100 | |
101 // Subclasses can optionally override this to do MT safety protocol | |
102 // checks. It is called in an assert from all methods that perform | |
103 // updates on the set (and subclasses should also call it too). | |
104 virtual bool check_mt_safety() { return true; } | |
105 | |
106 // fill_in_ext_msg() writes the the values of the set's attributes | |
107 // in the custom err_msg (hrl_ext_msg). fill_in_ext_msg_extra() | |
108 // allows subclasses to append further information. | |
109 virtual void fill_in_ext_msg_extra(hrl_ext_msg* msg) { } | |
110 void fill_in_ext_msg(hrl_ext_msg* msg, const char* message); | |
111 | |
112 // It updates the fields of the set to reflect hr being added to | |
113 // the set. | |
114 inline void update_for_addition(HeapRegion* hr); | |
115 | |
116 // It updates the fields of the set to reflect hr being added to | |
117 // the set and tags the region appropriately. | |
118 inline void add_internal(HeapRegion* hr); | |
119 | |
120 // It updates the fields of the set to reflect hr being removed | |
121 // from the set. | |
122 inline void update_for_removal(HeapRegion* hr); | |
123 | |
124 // It updates the fields of the set to reflect hr being removed | |
125 // from the set and tags the region appropriately. | |
126 inline void remove_internal(HeapRegion* hr); | |
127 | |
128 // It clears all the fields of the sets. Note: it will not iterate | |
129 // over the set and remove regions from it. It assumes that the | |
130 // caller has already done so. It will literally just clear the fields. | |
131 virtual void clear(); | |
132 | |
133 HeapRegionSetBase(const char* name); | |
134 | |
135 public: | |
136 static void set_unrealistically_long_length(size_t len); | |
137 | |
138 const char* name() { return _name; } | |
139 | |
140 size_t length() { return _length; } | |
141 | |
142 bool is_empty() { return _length == 0; } | |
143 | |
144 size_t region_num() { return _region_num; } | |
145 | |
146 size_t total_capacity_bytes() { | |
147 return region_num() << HeapRegion::LogOfHRGrainBytes; | |
148 } | |
149 | |
150 size_t total_used_bytes() { return _total_used_bytes; } | |
151 | |
152 virtual void verify(); | |
153 void verify_start(); | |
154 void verify_next_region(HeapRegion* hr); | |
155 void verify_end(); | |
156 | |
157 #if HEAP_REGION_SET_FORCE_VERIFY | |
158 void verify_optional() { | |
159 verify(); | |
160 } | |
161 #else // HEAP_REGION_SET_FORCE_VERIFY | |
162 void verify_optional() { } | |
163 #endif // HEAP_REGION_SET_FORCE_VERIFY | |
164 | |
165 virtual void print_on(outputStream* out, bool print_contents = false); | |
166 }; | |
167 | |
168 // Customized err_msg for heap region sets. Apart from a | |
169 // assert/guarantee-specific message it also prints out the values of | |
170 // the fields of the associated set. This can be very helpful in | |
171 // diagnosing failures. | |
172 | |
173 class hrl_ext_msg : public hrl_err_msg { | |
174 public: | |
175 hrl_ext_msg(HeapRegionSetBase* set, const char* message) : hrl_err_msg("") { | |
176 set->fill_in_ext_msg(this, message); | |
177 } | |
178 }; | |
179 | |
180 // These two macros are provided for convenience, to keep the uses of | |
181 // these two asserts a bit more concise. | |
182 | |
183 #define hrl_assert_mt_safety_ok(_set_) \ | |
184 do { \ | |
185 assert((_set_)->check_mt_safety(), hrl_ext_msg((_set_), "MT safety")); \ | |
186 } while (0) | |
187 | |
188 #define hrl_assert_region_ok(_set_, _hr_, _expected_) \ | |
189 do { \ | |
190 assert((_set_)->verify_region((_hr_), (_expected_)), \ | |
191 hrl_ext_msg((_set_), "region verification")); \ | |
192 } while (0) | |
193 | |
194 //////////////////// HeapRegionSet //////////////////// | |
195 | |
196 #define hrl_assert_sets_match(_set1_, _set2_) \ | |
197 do { \ | |
198 assert(((_set1_)->regions_humongous() == \ | |
199 (_set2_)->regions_humongous()) && \ | |
200 ((_set1_)->regions_empty() == (_set2_)->regions_empty()), \ | |
201 hrl_err_msg("the contents of set %s and set %s should match", \ | |
202 (_set1_)->name(), (_set2_)->name())); \ | |
203 } while (0) | |
204 | |
205 // This class represents heap region sets whose members are not | |
206 // explicitly tracked. It's helpful to group regions using such sets | |
207 // so that we can reason about all the region groups in the heap using | |
208 // the same interface (namely, the HeapRegionSetBase API). | |
209 | |
210 class HeapRegionSet : public HeapRegionSetBase { | |
211 protected: | |
212 virtual const char* verify_region_extra(HeapRegion* hr) { | |
213 if (hr->next() != NULL) { | |
214 return "next() should always be NULL as we do not link the regions"; | |
215 } | |
216 | |
217 return HeapRegionSetBase::verify_region_extra(hr); | |
218 } | |
219 | |
220 HeapRegionSet(const char* name) : HeapRegionSetBase(name) { | |
221 clear(); | |
222 } | |
223 | |
224 public: | |
225 // It adds hr to the set. The region should not be a member of | |
226 // another set. | |
227 inline void add(HeapRegion* hr); | |
228 | |
229 // It removes hr from the set. The region should be a member of | |
230 // this set. | |
231 inline void remove(HeapRegion* hr); | |
232 | |
233 // It removes a region from the set. Instead of updating the fields | |
234 // of the set to reflect this removal, it accumulates the updates | |
235 // in proxy_set. The idea is that proxy_set is thread-local to | |
236 // avoid multiple threads updating the fields of the set | |
237 // concurrently and having to synchronize. The method | |
238 // update_from_proxy() will update the fields of the set from the | |
239 // proxy_set. | |
240 inline void remove_with_proxy(HeapRegion* hr, HeapRegionSet* proxy_set); | |
241 | |
242 // After multiple calls to remove_with_proxy() the updates to the | |
243 // fields of the set are accumulated in proxy_set. This call | |
244 // updates the fields of the set from proxy_set. | |
245 void update_from_proxy(HeapRegionSet* proxy_set); | |
246 }; | |
247 | |
248 //////////////////// HeapRegionLinkedList //////////////////// | |
249 | |
250 // A set that links all the regions added to it in a singly-linked | |
251 // list. We should try to avoid doing operations that iterate over | |
252 // such lists in performance critical paths. Typically we should | |
253 // add / remove one region at a time or concatenate two lists. All | |
254 // those operations are done in constant time. | |
255 | |
256 class HeapRegionLinkedListIterator; | |
257 | |
258 class HeapRegionLinkedList : public HeapRegionSetBase { | |
259 friend class HeapRegionLinkedListIterator; | |
260 | |
261 private: | |
262 HeapRegion* _head; | |
263 HeapRegion* _tail; | |
264 | |
265 // These are provided for use by the friend classes. | |
266 HeapRegion* head() { return _head; } | |
267 HeapRegion* tail() { return _tail; } | |
268 | |
269 protected: | |
270 virtual void fill_in_ext_msg_extra(hrl_ext_msg* msg); | |
271 | |
272 // See the comment for HeapRegionSetBase::clear() | |
273 virtual void clear(); | |
274 | |
275 HeapRegionLinkedList(const char* name) : HeapRegionSetBase(name) { | |
276 clear(); | |
277 } | |
278 | |
279 public: | |
280 // It adds hr to the list as the new tail. The region should not be | |
281 // a member of another set. | |
282 inline void add_as_tail(HeapRegion* hr); | |
283 | |
284 // It removes and returns the head of the list. It assumes that the | |
285 // list is not empty so it will return a non-NULL value. | |
286 inline HeapRegion* remove_head(); | |
287 | |
288 // Convenience method. | |
289 inline HeapRegion* remove_head_or_null(); | |
290 | |
291 // It moves the regions from from_list to this list and empties | |
292 // from_list. The new regions will appear in the same order as they | |
293 // were in from_list and be linked in the end of this list. | |
294 void add_as_tail(HeapRegionLinkedList* from_list); | |
295 | |
296 // It empties the list by removing all regions from it. | |
297 void remove_all(); | |
298 | |
299 // It removes all regions in the list that are pending for removal | |
300 // (i.e., they have been tagged with "pending_removal"). The list | |
301 // must not be empty, target_count should reflect the exact number | |
302 // of regions that are pending for removal in the list, and | |
303 // target_count should be > 1 (currently, we never need to remove a | |
304 // single region using this). | |
305 void remove_all_pending(size_t target_count); | |
306 | |
307 virtual void verify(); | |
308 | |
309 virtual void print_on(outputStream* out, bool print_contents = false); | |
310 }; | |
311 | |
312 //////////////////// HeapRegionLinkedList //////////////////// | |
313 | |
314 // Iterator class that provides a convenient way to iterator over the | |
315 // regions in a HeapRegionLinkedList instance. | |
316 | |
317 class HeapRegionLinkedListIterator : public StackObj { | |
318 private: | |
319 HeapRegionLinkedList* _list; | |
320 HeapRegion* _curr; | |
321 | |
322 public: | |
323 bool more_available() { | |
324 return _curr != NULL; | |
325 } | |
326 | |
327 HeapRegion* get_next() { | |
328 assert(more_available(), | |
329 "get_next() should be called when more regions are available"); | |
330 | |
331 // If we are going to introduce a count in the iterator we should | |
332 // do the "cycle" check. | |
333 | |
334 HeapRegion* hr = _curr; | |
335 assert(_list->verify_region(hr, _list), "region verification"); | |
336 _curr = hr->next(); | |
337 return hr; | |
338 } | |
339 | |
340 HeapRegionLinkedListIterator(HeapRegionLinkedList* list) | |
341 : _curr(NULL), _list(list) { | |
342 _curr = list->head(); | |
343 } | |
344 }; | |
345 | |
346 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP |