1 /*
2 * Copyright (c) 2011, 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
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 HRS_ERR_MSG_BUFSZ 512
32 typedef FormatBuffer<HRS_ERR_MSG_BUFSZ> hrs_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 class hrs_ext_msg;
42
43 class HRSMtSafeChecker : public CHeapObj<mtGC> {
44 public:
45 virtual bool check() = 0;
46 };
47
48 class MasterFreeRegionListMtSafeChecker : public HRSMtSafeChecker { public: bool check(); };
49 class SecondaryFreeRegionListMtSafeChecker : public HRSMtSafeChecker { public: bool check(); };
50 class HumongousRegionSetMtSafeChecker : public HRSMtSafeChecker { public: bool check(); };
51 class OldRegionSetMtSafeChecker : public HRSMtSafeChecker { public: bool check(); };
52
53 class HeapRegionSetCount VALUE_OBJ_CLASS_SPEC {
54 friend class VMStructs;
55 uint _length;
56 size_t _capacity;
57
58 public:
59 HeapRegionSetCount() : _length(0), _capacity(0) { }
60
61 const uint length() const { return _length; }
62 const size_t capacity() const { return _capacity; }
63
64 void increment(uint length_to_add, size_t capacity_to_add) {
65 _length += length_to_add;
66 _capacity += capacity_to_add;
67 }
68
69 void decrement(const uint length_to_remove, const size_t capacity_to_remove) {
70 _length -= length_to_remove;
71 _capacity -= capacity_to_remove;
72 }
73 };
74
75 //////////////////// HeapRegionSetBase ////////////////////
76
77 // Base class for all the classes that represent heap region sets. It
78 // contains the basic attributes that each set needs to maintain
79 // (e.g., length, region num, used bytes sum) plus any shared
80 // functionality (e.g., verification).
81
82 class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC {
83 friend class VMStructs;
84 private:
85 bool _is_humongous;
86 bool _is_empty;
87 bool _is_linked;
88 HRSMtSafeChecker* _mt_safety_checker;
89
90 protected:
91 // The number of regions added to the set. If the set contains
92 // only humongous regions, this reflects only 'starts humongous'
93 // regions and does not include 'continues humongous' ones.
94 HeapRegionSetCount _count;
95
96 const char* _name;
97
98 bool _verify_in_progress;
99
100 // verify_region() is used to ensure that the contents of a region
101 // added to / removed from a set are consistent.
102 void verify_region(HeapRegion* hr) PRODUCT_RETURN;
103
104 // Indicates whether all regions in the set should be humongous or
105 // not. Only used during verification.
106 bool regions_humongous() { return _is_humongous; }
107
108 // Indicates whether all regions in the set should be empty or
109 // not. Only used during verification.
110 bool regions_empty() { return _is_empty; }
111
112 bool regions_linked() { return _is_linked; }
113
114 bool check_mt_safety() {
115 if (_mt_safety_checker != NULL) {
116 _mt_safety_checker->check();
117 }
118 return true;
119 }
120
121 virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg) { }
122
123 HeapRegionSetBase(const char* name, bool humongous, bool empty, bool linked, HRSMtSafeChecker* mt_safety_checker);
124
125 public:
126 const char* name() { return _name; }
127
128 uint length() { return _count.length(); }
129
130 bool is_empty() { return _count.length() == 0; }
131
132 size_t total_capacity_bytes() {
133 return _count.capacity();
134 }
135
136 // It updates the fields of the set to reflect hr being added to
137 // the set and tags the region appropriately.
138 inline void add(HeapRegion* hr);
139
140 // It updates the fields of the set to reflect hr being removed
141 // from the set and tags the region appropriately.
142 inline void remove(HeapRegion* hr);
143
144 // fill_in_ext_msg() writes the the values of the set's attributes
145 // in the custom err_msg (hrs_ext_msg). fill_in_ext_msg_extra()
146 // allows subclasses to append further information.
147 void fill_in_ext_msg(hrs_ext_msg* msg, const char* message);
148
149 virtual void verify();
150 void verify_start();
151 void verify_next_region(HeapRegion* hr);
152 void verify_end();
153
154 #if HEAP_REGION_SET_FORCE_VERIFY
155 void verify_optional() {
156 verify();
157 }
158 #else // HEAP_REGION_SET_FORCE_VERIFY
159 void verify_optional() { }
160 #endif // HEAP_REGION_SET_FORCE_VERIFY
161
162 virtual void print_on(outputStream* out, bool print_contents = false);
163 };
164
165 // Customized err_msg for heap region sets. Apart from a
166 // assert/guarantee-specific message it also prints out the values of
167 // the fields of the associated set. This can be very helpful in
168 // diagnosing failures.
169 class hrs_ext_msg : public hrs_err_msg {
170 public:
171 hrs_ext_msg(HeapRegionSetBase* set, const char* message) : hrs_err_msg("") {
172 set->fill_in_ext_msg(this, message);
173 }
174 };
175
176 //////////////////// HeapRegionSet ////////////////////
177
178 #define hrs_assert_sets_match(_set1_, _set2_) \
179 do { \
180 assert(((_set1_)->regions_humongous() == \
181 (_set2_)->regions_humongous()) && \
182 ((_set1_)->regions_empty() == (_set2_)->regions_empty()), \
183 hrs_err_msg("the contents of set %s and set %s should match", \
184 (_set1_)->name(), (_set2_)->name())); \
185 } while (0)
186
187 // This class represents heap region sets whose members are not
188 // explicitly tracked. It's helpful to group regions using such sets
189 // so that we can reason about all the region groups in the heap using
190 // the same interface (namely, the HeapRegionSetBase API).
191
192 class HeapRegionSet : public HeapRegionSetBase {
193 public:
194 HeapRegionSet(const char* name, bool humongous, HRSMtSafeChecker* mt_safety_checker):
195 HeapRegionSetBase(name, humongous, false /* empty */, false /* linked */, mt_safety_checker) { }
196
197 void bulk_remove(const HeapRegionSetCount& removed) {
198 _count.decrement(removed.length(), removed.capacity());
199 }
200 };
201
202 //////////////////// HeapRegionLinkedList ////////////////////
203
204 // A set that links all the regions added to it in a singly-linked
205 // list. We should try to avoid doing operations that iterate over
206 // such lists in performance critical paths. Typically we should
207 // add / remove one region at a time or concatenate two lists. All
208 // those operations are done in constant time.
209
210 class FreeRegionListIterator;
211
212 class FreeRegionList : public HeapRegionSetBase {
213 friend class FreeRegionListIterator;
214
215 private:
216 HeapRegion* _head;
217 HeapRegion* _tail;
218
219 protected:
220 virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg);
221
222 // See the comment for HeapRegionSetBase::clear()
223 virtual void clear();
224
225 public:
226 FreeRegionList(const char* name, HRSMtSafeChecker* mt_safety_checker):
227 HeapRegionSetBase(name, false /* humongous */, true /* empty */, true /* linked */, mt_safety_checker) {
228 clear();
229 }
230
231 void verify_list();
232
233 HeapRegion* head() { return _head; }
234 HeapRegion* tail() { return _tail; }
235
236 static uint _unrealistically_long_length;
237 static void set_unrealistically_long_length(uint len);
238
239 // It adds hr to the list as the new head. The region should not be
240 // a member of another set.
241 inline void add_as_head(HeapRegion* hr);
242
243 // It adds hr to the list as the new tail. The region should not be
244 // a member of another set.
245 inline void add_as_tail(HeapRegion* hr);
246
247 // It removes and returns the head of the list. It assumes that the
248 // list is not empty so it will return a non-NULL value.
249 inline HeapRegion* remove_head();
250
251 // Convenience method.
252 inline HeapRegion* remove_head_or_null();
253
254 // It moves the regions from from_list to this list and empties
255 // from_list. The new regions will appear in the same order as they
256 // were in from_list and be linked in the beginning of this list.
257 void add_as_head(FreeRegionList* from_list);
258
259 // It moves the regions from from_list to this list and empties
260 // from_list. The new regions will appear in the same order as they
261 // were in from_list and be linked in the end of this list.
262 void add_as_tail(FreeRegionList* from_list);
263
264 // It empties the list by removing all regions from it.
265 void remove_all();
266
267 // It removes all regions in the list that are pending for removal
268 // (i.e., they have been tagged with "pending_removal"). The list
269 // must not be empty, target_count should reflect the exact number
270 // of regions that are pending for removal in the list, and
271 // target_count should be > 1 (currently, we never need to remove a
272 // single region using this).
273 void remove_all_pending(uint target_count);
274
275 virtual void verify();
276
277 virtual void print_on(outputStream* out, bool print_contents = false);
278 };
279
280 //////////////////// FreeRegionListIterator ////////////////////
281
282 // Iterator class that provides a convenient way to iterate over the
283 // regions of a HeapRegionLinkedList instance.
284
285 class FreeRegionListIterator : public StackObj {
286 private:
287 FreeRegionList* _list;
288 HeapRegion* _curr;
289
290 public:
291 bool more_available() {
292 return _curr != NULL;
293 }
294
295 HeapRegion* get_next() {
296 assert(more_available(),
297 "get_next() should be called when more regions are available");
298
299 // If we are going to introduce a count in the iterator we should
300 // do the "cycle" check.
301
302 HeapRegion* hr = _curr;
303 _list->verify_region(hr);
304 _curr = hr->next();
305 return hr;
306 }
307
308 FreeRegionListIterator(FreeRegionList* list)
309 : _curr(NULL), _list(list) {
310 _curr = list->head();
311 }
312 };
313
314 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP