Mercurial > hg > graal-jvmci-8
annotate src/share/vm/gc_implementation/g1/g1RemSet.hpp @ 829:30b9b25b9cc1
6850869: G1: RSet "scrubbing" scrubs too much
Summary: RSet scrubbing incorrectly deletes RSet entries that point to regions tagged as "continues humongous" due to a race when RSet scrubbing iterates over regions in parallel.
Reviewed-by: apetrusenko, iveresov
author | tonyp |
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date | Wed, 24 Jun 2009 11:42:03 -0400 |
parents | 315a5d70b295 |
children | df6caf649ff7 |
rev | line source |
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342 | 1 /* |
579 | 2 * Copyright 2001-2009 Sun Microsystems, Inc. All Rights Reserved. |
342 | 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 // A G1RemSet provides ways of iterating over pointers into a selected | |
26 // collection set. | |
27 | |
28 class G1CollectedHeap; | |
29 class CardTableModRefBarrierSet; | |
30 class HRInto_G1RemSet; | |
31 class ConcurrentG1Refine; | |
32 | |
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33 class G1RemSet: public CHeapObj { |
342 | 34 protected: |
35 G1CollectedHeap* _g1; | |
36 unsigned _conc_refine_cards; | |
37 size_t n_workers(); | |
38 | |
39 public: | |
40 G1RemSet(G1CollectedHeap* g1) : | |
794 | 41 _g1(g1), _conc_refine_cards(0) |
342 | 42 {} |
43 | |
44 // Invoke "blk->do_oop" on all pointers into the CS in object in regions | |
45 // outside the CS (having invoked "blk->set_region" to set the "from" | |
46 // region correctly beforehand.) The "worker_i" param is for the | |
47 // parallel case where the number of the worker thread calling this | |
48 // function can be helpful in partitioning the work to be done. It | |
49 // should be the same as the "i" passed to the calling thread's | |
50 // work(i) function. In the sequential case this param will be ingored. | |
51 virtual void oops_into_collection_set_do(OopsInHeapRegionClosure* blk, | |
52 int worker_i) = 0; | |
53 | |
54 // Prepare for and cleanup after an oops_into_collection_set_do | |
55 // call. Must call each of these once before and after (in sequential | |
56 // code) any threads call oops into collection set do. (This offers an | |
57 // opportunity to sequential setup and teardown of structures needed by a | |
58 // parallel iteration over the CS's RS.) | |
59 virtual void prepare_for_oops_into_collection_set_do() = 0; | |
60 virtual void cleanup_after_oops_into_collection_set_do() = 0; | |
61 | |
62 // If "this" is of the given subtype, return "this", else "NULL". | |
63 virtual HRInto_G1RemSet* as_HRInto_G1RemSet() { return NULL; } | |
64 | |
65 // Record, if necessary, the fact that *p (where "p" is in region "from") | |
66 // has changed to its new value. | |
67 virtual void write_ref(HeapRegion* from, oop* p) = 0; | |
68 virtual void par_write_ref(HeapRegion* from, oop* p, int tid) = 0; | |
69 | |
70 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region | |
71 // or card, respectively, such that a region or card with a corresponding | |
72 // 0 bit contains no part of any live object. Eliminates any remembered | |
73 // set entries that correspond to dead heap ranges. | |
74 virtual void scrub(BitMap* region_bm, BitMap* card_bm) = 0; | |
75 // Like the above, but assumes is called in parallel: "worker_num" is the | |
76 // parallel thread id of the current thread, and "claim_val" is the | |
77 // value that should be used to claim heap regions. | |
78 virtual void scrub_par(BitMap* region_bm, BitMap* card_bm, | |
79 int worker_num, int claim_val) = 0; | |
80 | |
81 // Refine the card corresponding to "card_ptr". If "sts" is non-NULL, | |
82 // join and leave around parts that must be atomic wrt GC. (NULL means | |
83 // being done at a safepoint.) | |
84 virtual void concurrentRefineOneCard(jbyte* card_ptr, int worker_i) {} | |
85 | |
86 // Print any relevant summary info. | |
87 virtual void print_summary_info() {} | |
88 | |
89 // Prepare remebered set for verification. | |
90 virtual void prepare_for_verify() {}; | |
91 }; | |
92 | |
93 | |
94 // The simplest possible G1RemSet: iterates over all objects in non-CS | |
95 // regions, searching for pointers into the CS. | |
96 class StupidG1RemSet: public G1RemSet { | |
97 public: | |
98 StupidG1RemSet(G1CollectedHeap* g1) : G1RemSet(g1) {} | |
99 | |
100 void oops_into_collection_set_do(OopsInHeapRegionClosure* blk, | |
101 int worker_i); | |
102 | |
103 void prepare_for_oops_into_collection_set_do() {} | |
104 void cleanup_after_oops_into_collection_set_do() {} | |
105 | |
106 // Nothing is necessary in the version below. | |
107 void write_ref(HeapRegion* from, oop* p) {} | |
108 void par_write_ref(HeapRegion* from, oop* p, int tid) {} | |
109 | |
110 void scrub(BitMap* region_bm, BitMap* card_bm) {} | |
111 void scrub_par(BitMap* region_bm, BitMap* card_bm, | |
112 int worker_num, int claim_val) {} | |
113 | |
114 }; | |
115 | |
116 // A G1RemSet in which each heap region has a rem set that records the | |
117 // external heap references into it. Uses a mod ref bs to track updates, | |
118 // so that they can be used to update the individual region remsets. | |
119 | |
120 class HRInto_G1RemSet: public G1RemSet { | |
121 protected: | |
122 enum SomePrivateConstants { | |
123 UpdateRStoMergeSync = 0, | |
124 MergeRStoDoDirtySync = 1, | |
125 DoDirtySync = 2, | |
126 LastSync = 3, | |
127 | |
128 SeqTask = 0, | |
129 NumSeqTasks = 1 | |
130 }; | |
131 | |
132 CardTableModRefBS* _ct_bs; | |
133 SubTasksDone* _seq_task; | |
134 G1CollectorPolicy* _g1p; | |
135 | |
136 ConcurrentG1Refine* _cg1r; | |
137 | |
138 size_t* _cards_scanned; | |
139 size_t _total_cards_scanned; | |
140 | |
141 // _par_traversal_in_progress is "true" iff a parallel traversal is in | |
142 // progress. If so, then cards added to remembered sets should also have | |
143 // their references into the collection summarized in "_new_refs". | |
144 bool _par_traversal_in_progress; | |
794 | 145 void set_par_traversal(bool b) { _par_traversal_in_progress = b; } |
342 | 146 GrowableArray<oop*>** _new_refs; |
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147 void new_refs_iterate(OopClosure* cl); |
342 | 148 |
149 public: | |
150 // This is called to reset dual hash tables after the gc pause | |
151 // is finished and the initial hash table is no longer being | |
152 // scanned. | |
153 void cleanupHRRS(); | |
154 | |
155 HRInto_G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs); | |
156 ~HRInto_G1RemSet(); | |
157 | |
158 void oops_into_collection_set_do(OopsInHeapRegionClosure* blk, | |
159 int worker_i); | |
160 | |
161 void prepare_for_oops_into_collection_set_do(); | |
162 void cleanup_after_oops_into_collection_set_do(); | |
163 void scanRS(OopsInHeapRegionClosure* oc, int worker_i); | |
164 void scanNewRefsRS(OopsInHeapRegionClosure* oc, int worker_i); | |
165 void updateRS(int worker_i); | |
166 HeapRegion* calculateStartRegion(int i); | |
167 | |
168 HRInto_G1RemSet* as_HRInto_G1RemSet() { return this; } | |
169 | |
170 CardTableModRefBS* ct_bs() { return _ct_bs; } | |
171 size_t cardsScanned() { return _total_cards_scanned; } | |
172 | |
173 // Record, if necessary, the fact that *p (where "p" is in region "from", | |
174 // which is required to be non-NULL) has changed to a new non-NULL value. | |
175 inline void write_ref(HeapRegion* from, oop* p); | |
176 // The "_nv" version is the same; it exists just so that it is not virtual. | |
177 inline void write_ref_nv(HeapRegion* from, oop* p); | |
178 | |
179 inline bool self_forwarded(oop obj); | |
180 inline void par_write_ref(HeapRegion* from, oop* p, int tid); | |
181 | |
182 void scrub(BitMap* region_bm, BitMap* card_bm); | |
183 void scrub_par(BitMap* region_bm, BitMap* card_bm, | |
184 int worker_num, int claim_val); | |
185 | |
186 virtual void concurrentRefineOneCard(jbyte* card_ptr, int worker_i); | |
187 | |
188 virtual void print_summary_info(); | |
189 virtual void prepare_for_verify(); | |
190 }; | |
191 | |
192 #define G1_REM_SET_LOGGING 0 | |
193 | |
194 class CountNonCleanMemRegionClosure: public MemRegionClosure { | |
195 G1CollectedHeap* _g1; | |
196 int _n; | |
197 HeapWord* _start_first; | |
198 public: | |
199 CountNonCleanMemRegionClosure(G1CollectedHeap* g1) : | |
200 _g1(g1), _n(0), _start_first(NULL) | |
201 {} | |
202 void do_MemRegion(MemRegion mr); | |
203 int n() { return _n; }; | |
204 HeapWord* start_first() { return _start_first; } | |
205 }; | |
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206 |
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207 class UpdateRSOopClosure: public OopClosure { |
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208 HeapRegion* _from; |
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209 HRInto_G1RemSet* _rs; |
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210 int _worker_i; |
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211 public: |
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212 UpdateRSOopClosure(HRInto_G1RemSet* rs, int worker_i = 0) : |
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213 _from(NULL), _rs(rs), _worker_i(worker_i) { |
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214 guarantee(_rs != NULL, "Requires an HRIntoG1RemSet"); |
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215 } |
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216 |
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217 void set_from(HeapRegion* from) { |
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218 assert(from != NULL, "from region must be non-NULL"); |
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219 _from = from; |
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220 } |
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221 |
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222 virtual void do_oop(narrowOop* p); |
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223 virtual void do_oop(oop* p); |
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224 |
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225 // Override: this closure is idempotent. |
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226 // bool idempotent() { return true; } |
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227 bool apply_to_weak_ref_discovered_field() { return true; } |
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228 }; |
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229 |