Mercurial > hg > truffle
annotate src/share/vm/memory/cardTableModRefBS.cpp @ 803:27b728fd1281 jdk7-b61
Merge
author | trims |
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date | Thu, 11 Jun 2009 21:01:07 -0700 |
parents | 7bb995fbd3c0 |
children | ff004bcd2596 |
rev | line source |
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0 | 1 /* |
579 | 2 * Copyright 2000-2009 Sun Microsystems, Inc. All Rights Reserved. |
0 | 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 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and | |
26 // enumerate ref fields that have been modified (since the last | |
27 // enumeration.) | |
28 | |
29 # include "incls/_precompiled.incl" | |
30 # include "incls/_cardTableModRefBS.cpp.incl" | |
31 | |
32 size_t CardTableModRefBS::cards_required(size_t covered_words) | |
33 { | |
34 // Add one for a guard card, used to detect errors. | |
35 const size_t words = align_size_up(covered_words, card_size_in_words); | |
36 return words / card_size_in_words + 1; | |
37 } | |
38 | |
39 size_t CardTableModRefBS::compute_byte_map_size() | |
40 { | |
41 assert(_guard_index == cards_required(_whole_heap.word_size()) - 1, | |
42 "unitialized, check declaration order"); | |
43 assert(_page_size != 0, "unitialized, check declaration order"); | |
44 const size_t granularity = os::vm_allocation_granularity(); | |
45 return align_size_up(_guard_index + 1, MAX2(_page_size, granularity)); | |
46 } | |
47 | |
48 CardTableModRefBS::CardTableModRefBS(MemRegion whole_heap, | |
49 int max_covered_regions): | |
50 ModRefBarrierSet(max_covered_regions), | |
51 _whole_heap(whole_heap), | |
52 _guard_index(cards_required(whole_heap.word_size()) - 1), | |
53 _last_valid_index(_guard_index - 1), | |
21 | 54 _page_size(os::vm_page_size()), |
0 | 55 _byte_map_size(compute_byte_map_size()) |
56 { | |
57 _kind = BarrierSet::CardTableModRef; | |
58 | |
59 HeapWord* low_bound = _whole_heap.start(); | |
60 HeapWord* high_bound = _whole_heap.end(); | |
61 assert((uintptr_t(low_bound) & (card_size - 1)) == 0, "heap must start at card boundary"); | |
62 assert((uintptr_t(high_bound) & (card_size - 1)) == 0, "heap must end at card boundary"); | |
63 | |
64 assert(card_size <= 512, "card_size must be less than 512"); // why? | |
65 | |
66 _covered = new MemRegion[max_covered_regions]; | |
67 _committed = new MemRegion[max_covered_regions]; | |
68 if (_covered == NULL || _committed == NULL) | |
69 vm_exit_during_initialization("couldn't alloc card table covered region set."); | |
70 int i; | |
71 for (i = 0; i < max_covered_regions; i++) { | |
72 _covered[i].set_word_size(0); | |
73 _committed[i].set_word_size(0); | |
74 } | |
75 _cur_covered_regions = 0; | |
76 | |
77 const size_t rs_align = _page_size == (size_t) os::vm_page_size() ? 0 : | |
78 MAX2(_page_size, (size_t) os::vm_allocation_granularity()); | |
79 ReservedSpace heap_rs(_byte_map_size, rs_align, false); | |
80 os::trace_page_sizes("card table", _guard_index + 1, _guard_index + 1, | |
81 _page_size, heap_rs.base(), heap_rs.size()); | |
82 if (!heap_rs.is_reserved()) { | |
83 vm_exit_during_initialization("Could not reserve enough space for the " | |
84 "card marking array"); | |
85 } | |
86 | |
87 // The assember store_check code will do an unsigned shift of the oop, | |
88 // then add it to byte_map_base, i.e. | |
89 // | |
90 // _byte_map = byte_map_base + (uintptr_t(low_bound) >> card_shift) | |
91 _byte_map = (jbyte*) heap_rs.base(); | |
92 byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift); | |
93 assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map"); | |
94 assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map"); | |
95 | |
96 jbyte* guard_card = &_byte_map[_guard_index]; | |
97 uintptr_t guard_page = align_size_down((uintptr_t)guard_card, _page_size); | |
98 _guard_region = MemRegion((HeapWord*)guard_page, _page_size); | |
99 if (!os::commit_memory((char*)guard_page, _page_size, _page_size)) { | |
100 // Do better than this for Merlin | |
101 vm_exit_out_of_memory(_page_size, "card table last card"); | |
102 } | |
103 *guard_card = last_card; | |
104 | |
105 _lowest_non_clean = | |
106 NEW_C_HEAP_ARRAY(CardArr, max_covered_regions); | |
107 _lowest_non_clean_chunk_size = | |
108 NEW_C_HEAP_ARRAY(size_t, max_covered_regions); | |
109 _lowest_non_clean_base_chunk_index = | |
110 NEW_C_HEAP_ARRAY(uintptr_t, max_covered_regions); | |
111 _last_LNC_resizing_collection = | |
112 NEW_C_HEAP_ARRAY(int, max_covered_regions); | |
113 if (_lowest_non_clean == NULL | |
114 || _lowest_non_clean_chunk_size == NULL | |
115 || _lowest_non_clean_base_chunk_index == NULL | |
116 || _last_LNC_resizing_collection == NULL) | |
117 vm_exit_during_initialization("couldn't allocate an LNC array."); | |
118 for (i = 0; i < max_covered_regions; i++) { | |
119 _lowest_non_clean[i] = NULL; | |
120 _lowest_non_clean_chunk_size[i] = 0; | |
121 _last_LNC_resizing_collection[i] = -1; | |
122 } | |
123 | |
124 if (TraceCardTableModRefBS) { | |
125 gclog_or_tty->print_cr("CardTableModRefBS::CardTableModRefBS: "); | |
126 gclog_or_tty->print_cr(" " | |
127 " &_byte_map[0]: " INTPTR_FORMAT | |
128 " &_byte_map[_last_valid_index]: " INTPTR_FORMAT, | |
129 &_byte_map[0], | |
130 &_byte_map[_last_valid_index]); | |
131 gclog_or_tty->print_cr(" " | |
132 " byte_map_base: " INTPTR_FORMAT, | |
133 byte_map_base); | |
134 } | |
135 } | |
136 | |
137 int CardTableModRefBS::find_covering_region_by_base(HeapWord* base) { | |
138 int i; | |
139 for (i = 0; i < _cur_covered_regions; i++) { | |
140 if (_covered[i].start() == base) return i; | |
141 if (_covered[i].start() > base) break; | |
142 } | |
143 // If we didn't find it, create a new one. | |
144 assert(_cur_covered_regions < _max_covered_regions, | |
145 "too many covered regions"); | |
146 // Move the ones above up, to maintain sorted order. | |
147 for (int j = _cur_covered_regions; j > i; j--) { | |
148 _covered[j] = _covered[j-1]; | |
149 _committed[j] = _committed[j-1]; | |
150 } | |
151 int res = i; | |
152 _cur_covered_regions++; | |
153 _covered[res].set_start(base); | |
154 _covered[res].set_word_size(0); | |
155 jbyte* ct_start = byte_for(base); | |
156 uintptr_t ct_start_aligned = align_size_down((uintptr_t)ct_start, _page_size); | |
157 _committed[res].set_start((HeapWord*)ct_start_aligned); | |
158 _committed[res].set_word_size(0); | |
159 return res; | |
160 } | |
161 | |
162 int CardTableModRefBS::find_covering_region_containing(HeapWord* addr) { | |
163 for (int i = 0; i < _cur_covered_regions; i++) { | |
164 if (_covered[i].contains(addr)) { | |
165 return i; | |
166 } | |
167 } | |
168 assert(0, "address outside of heap?"); | |
169 return -1; | |
170 } | |
171 | |
172 HeapWord* CardTableModRefBS::largest_prev_committed_end(int ind) const { | |
173 HeapWord* max_end = NULL; | |
174 for (int j = 0; j < ind; j++) { | |
175 HeapWord* this_end = _committed[j].end(); | |
176 if (this_end > max_end) max_end = this_end; | |
177 } | |
178 return max_end; | |
179 } | |
180 | |
181 MemRegion CardTableModRefBS::committed_unique_to_self(int self, | |
182 MemRegion mr) const { | |
183 MemRegion result = mr; | |
184 for (int r = 0; r < _cur_covered_regions; r += 1) { | |
185 if (r != self) { | |
186 result = result.minus(_committed[r]); | |
187 } | |
188 } | |
189 // Never include the guard page. | |
190 result = result.minus(_guard_region); | |
191 return result; | |
192 } | |
193 | |
194 void CardTableModRefBS::resize_covered_region(MemRegion new_region) { | |
195 // We don't change the start of a region, only the end. | |
196 assert(_whole_heap.contains(new_region), | |
197 "attempt to cover area not in reserved area"); | |
198 debug_only(verify_guard();) | |
208
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199 // collided is true if the expansion would push into another committed region |
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200 debug_only(bool collided = false;) |
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201 int const ind = find_covering_region_by_base(new_region.start()); |
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202 MemRegion const old_region = _covered[ind]; |
0 | 203 assert(old_region.start() == new_region.start(), "just checking"); |
204 if (new_region.word_size() != old_region.word_size()) { | |
205 // Commit new or uncommit old pages, if necessary. | |
206 MemRegion cur_committed = _committed[ind]; | |
207 // Extend the end of this _commited region | |
208 // to cover the end of any lower _committed regions. | |
209 // This forms overlapping regions, but never interior regions. | |
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210 HeapWord* const max_prev_end = largest_prev_committed_end(ind); |
0 | 211 if (max_prev_end > cur_committed.end()) { |
212 cur_committed.set_end(max_prev_end); | |
213 } | |
214 // Align the end up to a page size (starts are already aligned). | |
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215 jbyte* const new_end = byte_after(new_region.last()); |
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216 HeapWord* new_end_aligned = |
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217 (HeapWord*) align_size_up((uintptr_t)new_end, _page_size); |
0 | 218 assert(new_end_aligned >= (HeapWord*) new_end, |
219 "align up, but less"); | |
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220 // Check the other regions (excludes "ind") to ensure that |
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221 // the new_end_aligned does not intrude onto the committed |
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222 // space of another region. |
208
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223 int ri = 0; |
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224 for (ri = 0; ri < _cur_covered_regions; ri++) { |
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225 if (ri != ind) { |
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226 if (_committed[ri].contains(new_end_aligned)) { |
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227 // The prior check included in the assert |
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228 // (new_end_aligned >= _committed[ri].start()) |
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229 // is redundant with the "contains" test. |
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230 // Any region containing the new end |
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231 // should start at or beyond the region found (ind) |
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232 // for the new end (committed regions are not expected to |
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233 // be proper subsets of other committed regions). |
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234 assert(_committed[ri].start() >= _committed[ind].start(), |
208
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235 "New end of committed region is inconsistent"); |
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236 new_end_aligned = _committed[ri].start(); |
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237 // new_end_aligned can be equal to the start of its |
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238 // committed region (i.e., of "ind") if a second |
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239 // region following "ind" also start at the same location |
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240 // as "ind". |
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241 assert(new_end_aligned >= _committed[ind].start(), |
208
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242 "New end of committed region is before start"); |
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243 debug_only(collided = true;) |
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244 // Should only collide with 1 region |
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245 break; |
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246 } |
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247 } |
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248 } |
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249 #ifdef ASSERT |
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250 for (++ri; ri < _cur_covered_regions; ri++) { |
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251 assert(!_committed[ri].contains(new_end_aligned), |
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252 "New end of committed region is in a second committed region"); |
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253 } |
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254 #endif |
0 | 255 // The guard page is always committed and should not be committed over. |
208
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256 HeapWord* const new_end_for_commit = MIN2(new_end_aligned, |
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257 _guard_region.start()); |
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258 |
0 | 259 if (new_end_for_commit > cur_committed.end()) { |
260 // Must commit new pages. | |
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261 MemRegion const new_committed = |
0 | 262 MemRegion(cur_committed.end(), new_end_for_commit); |
263 | |
264 assert(!new_committed.is_empty(), "Region should not be empty here"); | |
265 if (!os::commit_memory((char*)new_committed.start(), | |
266 new_committed.byte_size(), _page_size)) { | |
267 // Do better than this for Merlin | |
268 vm_exit_out_of_memory(new_committed.byte_size(), | |
269 "card table expansion"); | |
270 } | |
271 // Use new_end_aligned (as opposed to new_end_for_commit) because | |
272 // the cur_committed region may include the guard region. | |
273 } else if (new_end_aligned < cur_committed.end()) { | |
274 // Must uncommit pages. | |
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275 MemRegion const uncommit_region = |
0 | 276 committed_unique_to_self(ind, MemRegion(new_end_aligned, |
277 cur_committed.end())); | |
278 if (!uncommit_region.is_empty()) { | |
279 if (!os::uncommit_memory((char*)uncommit_region.start(), | |
280 uncommit_region.byte_size())) { | |
208
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281 assert(false, "Card table contraction failed"); |
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282 // The call failed so don't change the end of the |
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283 // committed region. This is better than taking the |
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284 // VM down. |
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285 new_end_aligned = _committed[ind].end(); |
0 | 286 } |
287 } | |
288 } | |
289 // In any case, we can reset the end of the current committed entry. | |
290 _committed[ind].set_end(new_end_aligned); | |
291 | |
292 // The default of 0 is not necessarily clean cards. | |
293 jbyte* entry; | |
294 if (old_region.last() < _whole_heap.start()) { | |
295 entry = byte_for(_whole_heap.start()); | |
296 } else { | |
297 entry = byte_after(old_region.last()); | |
298 } | |
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299 assert(index_for(new_region.last()) < _guard_index, |
0 | 300 "The guard card will be overwritten"); |
208
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301 // This line commented out cleans the newly expanded region and |
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302 // not the aligned up expanded region. |
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303 // jbyte* const end = byte_after(new_region.last()); |
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304 jbyte* const end = (jbyte*) new_end_for_commit; |
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305 assert((end >= byte_after(new_region.last())) || collided, |
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306 "Expect to be beyond new region unless impacting another region"); |
0 | 307 // do nothing if we resized downward. |
208
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308 #ifdef ASSERT |
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309 for (int ri = 0; ri < _cur_covered_regions; ri++) { |
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310 if (ri != ind) { |
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311 // The end of the new committed region should not |
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312 // be in any existing region unless it matches |
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313 // the start of the next region. |
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314 assert(!_committed[ri].contains(end) || |
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315 (_committed[ri].start() == (HeapWord*) end), |
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316 "Overlapping committed regions"); |
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317 } |
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318 } |
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319 #endif |
0 | 320 if (entry < end) { |
321 memset(entry, clean_card, pointer_delta(end, entry, sizeof(jbyte))); | |
322 } | |
323 } | |
324 // In any case, the covered size changes. | |
325 _covered[ind].set_word_size(new_region.word_size()); | |
326 if (TraceCardTableModRefBS) { | |
327 gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: "); | |
328 gclog_or_tty->print_cr(" " | |
329 " _covered[%d].start(): " INTPTR_FORMAT | |
330 " _covered[%d].last(): " INTPTR_FORMAT, | |
331 ind, _covered[ind].start(), | |
332 ind, _covered[ind].last()); | |
333 gclog_or_tty->print_cr(" " | |
334 " _committed[%d].start(): " INTPTR_FORMAT | |
335 " _committed[%d].last(): " INTPTR_FORMAT, | |
336 ind, _committed[ind].start(), | |
337 ind, _committed[ind].last()); | |
338 gclog_or_tty->print_cr(" " | |
339 " byte_for(start): " INTPTR_FORMAT | |
340 " byte_for(last): " INTPTR_FORMAT, | |
341 byte_for(_covered[ind].start()), | |
342 byte_for(_covered[ind].last())); | |
343 gclog_or_tty->print_cr(" " | |
344 " addr_for(start): " INTPTR_FORMAT | |
345 " addr_for(last): " INTPTR_FORMAT, | |
346 addr_for((jbyte*) _committed[ind].start()), | |
347 addr_for((jbyte*) _committed[ind].last())); | |
348 } | |
349 debug_only(verify_guard();) | |
350 } | |
351 | |
352 // Note that these versions are precise! The scanning code has to handle the | |
353 // fact that the write barrier may be either precise or imprecise. | |
354 | |
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355 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal) { |
0 | 356 inline_write_ref_field(field, newVal); |
357 } | |
358 | |
616
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359 /* |
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360 Claimed and deferred bits are used together in G1 during the evacuation |
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361 pause. These bits can have the following state transitions: |
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362 1. The claimed bit can be put over any other card state. Except that |
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363 the "dirty -> dirty and claimed" transition is checked for in |
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364 G1 code and is not used. |
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365 2. Deferred bit can be set only if the previous state of the card |
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366 was either clean or claimed. mark_card_deferred() is wait-free. |
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367 We do not care if the operation is be successful because if |
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368 it does not it will only result in duplicate entry in the update |
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369 buffer because of the "cache-miss". So it's not worth spinning. |
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370 */ |
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371 |
0 | 372 |
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373 bool CardTableModRefBS::claim_card(size_t card_index) { |
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374 jbyte val = _byte_map[card_index]; |
616
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375 assert(val != dirty_card_val(), "Shouldn't claim a dirty card"); |
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376 while (val == clean_card_val() || |
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377 (val & (clean_card_mask_val() | claimed_card_val())) != claimed_card_val()) { |
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378 jbyte new_val = val; |
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379 if (val == clean_card_val()) { |
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380 new_val = (jbyte)claimed_card_val(); |
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381 } else { |
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382 new_val = val | (jbyte)claimed_card_val(); |
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383 } |
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384 jbyte res = Atomic::cmpxchg(new_val, &_byte_map[card_index], val); |
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385 if (res == val) { |
342
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386 return true; |
616
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387 } |
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388 val = res; |
342
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389 } |
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390 return false; |
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391 } |
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392 |
616
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393 bool CardTableModRefBS::mark_card_deferred(size_t card_index) { |
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394 jbyte val = _byte_map[card_index]; |
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395 // It's already processed |
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396 if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) { |
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397 return false; |
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398 } |
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399 // Cached bit can be installed either on a clean card or on a claimed card. |
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400 jbyte new_val = val; |
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401 if (val == clean_card_val()) { |
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402 new_val = (jbyte)deferred_card_val(); |
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403 } else { |
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404 if (val & claimed_card_val()) { |
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405 new_val = val | (jbyte)deferred_card_val(); |
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406 } |
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407 } |
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408 if (new_val != val) { |
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409 Atomic::cmpxchg(new_val, &_byte_map[card_index], val); |
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410 } |
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411 return true; |
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412 } |
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413 |
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414 |
0 | 415 void CardTableModRefBS::non_clean_card_iterate(Space* sp, |
416 MemRegion mr, | |
417 DirtyCardToOopClosure* dcto_cl, | |
418 MemRegionClosure* cl, | |
419 bool clear) { | |
420 if (!mr.is_empty()) { | |
421 int n_threads = SharedHeap::heap()->n_par_threads(); | |
422 if (n_threads > 0) { | |
423 #ifndef SERIALGC | |
424 par_non_clean_card_iterate_work(sp, mr, dcto_cl, cl, clear, n_threads); | |
425 #else // SERIALGC | |
426 fatal("Parallel gc not supported here."); | |
427 #endif // SERIALGC | |
428 } else { | |
429 non_clean_card_iterate_work(mr, cl, clear); | |
430 } | |
431 } | |
432 } | |
433 | |
434 // NOTE: For this to work correctly, it is important that | |
435 // we look for non-clean cards below (so as to catch those | |
436 // marked precleaned), rather than look explicitly for dirty | |
437 // cards (and miss those marked precleaned). In that sense, | |
438 // the name precleaned is currently somewhat of a misnomer. | |
439 void CardTableModRefBS::non_clean_card_iterate_work(MemRegion mr, | |
440 MemRegionClosure* cl, | |
441 bool clear) { | |
442 // Figure out whether we have to worry about parallelism. | |
443 bool is_par = (SharedHeap::heap()->n_par_threads() > 1); | |
444 for (int i = 0; i < _cur_covered_regions; i++) { | |
445 MemRegion mri = mr.intersection(_covered[i]); | |
446 if (mri.word_size() > 0) { | |
447 jbyte* cur_entry = byte_for(mri.last()); | |
448 jbyte* limit = byte_for(mri.start()); | |
449 while (cur_entry >= limit) { | |
450 jbyte* next_entry = cur_entry - 1; | |
451 if (*cur_entry != clean_card) { | |
452 size_t non_clean_cards = 1; | |
453 // Should the next card be included in this range of dirty cards. | |
454 while (next_entry >= limit && *next_entry != clean_card) { | |
455 non_clean_cards++; | |
456 cur_entry = next_entry; | |
457 next_entry--; | |
458 } | |
459 // The memory region may not be on a card boundary. So that | |
460 // objects beyond the end of the region are not processed, make | |
461 // cur_cards precise with regard to the end of the memory region. | |
462 MemRegion cur_cards(addr_for(cur_entry), | |
463 non_clean_cards * card_size_in_words); | |
464 MemRegion dirty_region = cur_cards.intersection(mri); | |
465 if (clear) { | |
466 for (size_t i = 0; i < non_clean_cards; i++) { | |
467 // Clean the dirty cards (but leave the other non-clean | |
468 // alone.) If parallel, do the cleaning atomically. | |
469 jbyte cur_entry_val = cur_entry[i]; | |
470 if (card_is_dirty_wrt_gen_iter(cur_entry_val)) { | |
471 if (is_par) { | |
472 jbyte res = Atomic::cmpxchg(clean_card, &cur_entry[i], cur_entry_val); | |
473 assert(res != clean_card, | |
474 "Dirty card mysteriously cleaned"); | |
475 } else { | |
476 cur_entry[i] = clean_card; | |
477 } | |
478 } | |
479 } | |
480 } | |
481 cl->do_MemRegion(dirty_region); | |
482 } | |
483 cur_entry = next_entry; | |
484 } | |
485 } | |
486 } | |
487 } | |
488 | |
489 void CardTableModRefBS::mod_oop_in_space_iterate(Space* sp, | |
490 OopClosure* cl, | |
491 bool clear, | |
492 bool before_save_marks) { | |
493 // Note that dcto_cl is resource-allocated, so there is no | |
494 // corresponding "delete". | |
495 DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision()); | |
496 MemRegion used_mr; | |
497 if (before_save_marks) { | |
498 used_mr = sp->used_region_at_save_marks(); | |
499 } else { | |
500 used_mr = sp->used_region(); | |
501 } | |
502 non_clean_card_iterate(sp, used_mr, dcto_cl, dcto_cl, clear); | |
503 } | |
504 | |
505 void CardTableModRefBS::dirty_MemRegion(MemRegion mr) { | |
506 jbyte* cur = byte_for(mr.start()); | |
507 jbyte* last = byte_after(mr.last()); | |
508 while (cur < last) { | |
509 *cur = dirty_card; | |
510 cur++; | |
511 } | |
512 } | |
513 | |
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514 void CardTableModRefBS::invalidate(MemRegion mr, bool whole_heap) { |
0 | 515 for (int i = 0; i < _cur_covered_regions; i++) { |
516 MemRegion mri = mr.intersection(_covered[i]); | |
517 if (!mri.is_empty()) dirty_MemRegion(mri); | |
518 } | |
519 } | |
520 | |
521 void CardTableModRefBS::clear_MemRegion(MemRegion mr) { | |
522 // Be conservative: only clean cards entirely contained within the | |
523 // region. | |
524 jbyte* cur; | |
525 if (mr.start() == _whole_heap.start()) { | |
526 cur = byte_for(mr.start()); | |
527 } else { | |
528 assert(mr.start() > _whole_heap.start(), "mr is not covered."); | |
529 cur = byte_after(mr.start() - 1); | |
530 } | |
531 jbyte* last = byte_after(mr.last()); | |
532 memset(cur, clean_card, pointer_delta(last, cur, sizeof(jbyte))); | |
533 } | |
534 | |
535 void CardTableModRefBS::clear(MemRegion mr) { | |
536 for (int i = 0; i < _cur_covered_regions; i++) { | |
537 MemRegion mri = mr.intersection(_covered[i]); | |
538 if (!mri.is_empty()) clear_MemRegion(mri); | |
539 } | |
540 } | |
541 | |
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542 void CardTableModRefBS::dirty(MemRegion mr) { |
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543 jbyte* first = byte_for(mr.start()); |
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544 jbyte* last = byte_after(mr.last()); |
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545 memset(first, dirty_card, last-first); |
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546 } |
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547 |
0 | 548 // NOTES: |
549 // (1) Unlike mod_oop_in_space_iterate() above, dirty_card_iterate() | |
550 // iterates over dirty cards ranges in increasing address order. | |
551 void CardTableModRefBS::dirty_card_iterate(MemRegion mr, | |
552 MemRegionClosure* cl) { | |
553 for (int i = 0; i < _cur_covered_regions; i++) { | |
554 MemRegion mri = mr.intersection(_covered[i]); | |
555 if (!mri.is_empty()) { | |
556 jbyte *cur_entry, *next_entry, *limit; | |
557 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last()); | |
558 cur_entry <= limit; | |
559 cur_entry = next_entry) { | |
560 next_entry = cur_entry + 1; | |
561 if (*cur_entry == dirty_card) { | |
562 size_t dirty_cards; | |
563 // Accumulate maximal dirty card range, starting at cur_entry | |
564 for (dirty_cards = 1; | |
565 next_entry <= limit && *next_entry == dirty_card; | |
566 dirty_cards++, next_entry++); | |
567 MemRegion cur_cards(addr_for(cur_entry), | |
568 dirty_cards*card_size_in_words); | |
569 cl->do_MemRegion(cur_cards); | |
570 } | |
571 } | |
572 } | |
573 } | |
574 } | |
575 | |
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576 MemRegion CardTableModRefBS::dirty_card_range_after_reset(MemRegion mr, |
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577 bool reset, |
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578 int reset_val) { |
0 | 579 for (int i = 0; i < _cur_covered_regions; i++) { |
580 MemRegion mri = mr.intersection(_covered[i]); | |
581 if (!mri.is_empty()) { | |
582 jbyte* cur_entry, *next_entry, *limit; | |
583 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last()); | |
584 cur_entry <= limit; | |
585 cur_entry = next_entry) { | |
586 next_entry = cur_entry + 1; | |
587 if (*cur_entry == dirty_card) { | |
588 size_t dirty_cards; | |
589 // Accumulate maximal dirty card range, starting at cur_entry | |
590 for (dirty_cards = 1; | |
591 next_entry <= limit && *next_entry == dirty_card; | |
592 dirty_cards++, next_entry++); | |
593 MemRegion cur_cards(addr_for(cur_entry), | |
594 dirty_cards*card_size_in_words); | |
342
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595 if (reset) { |
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596 for (size_t i = 0; i < dirty_cards; i++) { |
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597 cur_entry[i] = reset_val; |
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598 } |
0 | 599 } |
600 return cur_cards; | |
601 } | |
602 } | |
603 } | |
604 } | |
605 return MemRegion(mr.end(), mr.end()); | |
606 } | |
607 | |
608 // Set all the dirty cards in the given region to "precleaned" state. | |
609 void CardTableModRefBS::preclean_dirty_cards(MemRegion mr) { | |
610 for (int i = 0; i < _cur_covered_regions; i++) { | |
611 MemRegion mri = mr.intersection(_covered[i]); | |
612 if (!mri.is_empty()) { | |
613 jbyte *cur_entry, *limit; | |
614 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last()); | |
615 cur_entry <= limit; | |
616 cur_entry++) { | |
617 if (*cur_entry == dirty_card) { | |
618 *cur_entry = precleaned_card; | |
619 } | |
620 } | |
621 } | |
622 } | |
623 } | |
624 | |
625 uintx CardTableModRefBS::ct_max_alignment_constraint() { | |
626 return card_size * os::vm_page_size(); | |
627 } | |
628 | |
629 void CardTableModRefBS::verify_guard() { | |
630 // For product build verification | |
631 guarantee(_byte_map[_guard_index] == last_card, | |
632 "card table guard has been modified"); | |
633 } | |
634 | |
635 void CardTableModRefBS::verify() { | |
636 verify_guard(); | |
637 } | |
638 | |
639 #ifndef PRODUCT | |
640 class GuaranteeNotModClosure: public MemRegionClosure { | |
641 CardTableModRefBS* _ct; | |
642 public: | |
643 GuaranteeNotModClosure(CardTableModRefBS* ct) : _ct(ct) {} | |
644 void do_MemRegion(MemRegion mr) { | |
645 jbyte* entry = _ct->byte_for(mr.start()); | |
646 guarantee(*entry != CardTableModRefBS::clean_card, | |
647 "Dirty card in region that should be clean"); | |
648 } | |
649 }; | |
650 | |
651 void CardTableModRefBS::verify_clean_region(MemRegion mr) { | |
652 GuaranteeNotModClosure blk(this); | |
653 non_clean_card_iterate_work(mr, &blk, false); | |
654 } | |
655 #endif | |
656 | |
657 bool CardTableModRefBSForCTRS::card_will_be_scanned(jbyte cv) { | |
658 return | |
659 CardTableModRefBS::card_will_be_scanned(cv) || | |
660 _rs->is_prev_nonclean_card_val(cv); | |
661 }; | |
662 | |
663 bool CardTableModRefBSForCTRS::card_may_have_been_dirty(jbyte cv) { | |
664 return | |
665 cv != clean_card && | |
666 (CardTableModRefBS::card_may_have_been_dirty(cv) || | |
667 CardTableRS::youngergen_may_have_been_dirty(cv)); | |
668 }; |