Tue, 23 Nov 2010 13:22:55 -0800
6989984: Use standard include model for Hospot
Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg
1 /*
2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
27 #include "gc_implementation/g1/heapRegionSeq.hpp"
28 #include "memory/allocation.hpp"
30 // Local to this file.
32 static int orderRegions(HeapRegion** hr1p, HeapRegion** hr2p) {
33 if ((*hr1p)->end() <= (*hr2p)->bottom()) return -1;
34 else if ((*hr2p)->end() <= (*hr1p)->bottom()) return 1;
35 else if (*hr1p == *hr2p) return 0;
36 else {
37 assert(false, "We should never compare distinct overlapping regions.");
38 }
39 return 0;
40 }
42 HeapRegionSeq::HeapRegionSeq(const size_t max_size) :
43 _alloc_search_start(0),
44 // The line below is the worst bit of C++ hackery I've ever written
45 // (Detlefs, 11/23). You should think of it as equivalent to
46 // "_regions(100, true)": initialize the growable array and inform it
47 // that it should allocate its elem array(s) on the C heap.
48 //
49 // The first argument, however, is actually a comma expression
50 // (set_allocation_type(this, C_HEAP), 100). The purpose of the
51 // set_allocation_type() call is to replace the default allocation
52 // type for embedded objects STACK_OR_EMBEDDED with C_HEAP. It will
53 // allow to pass the assert in GenericGrowableArray() which checks
54 // that a growable array object must be on C heap if elements are.
55 //
56 // Note: containing object is allocated on C heap since it is CHeapObj.
57 //
58 _regions((ResourceObj::set_allocation_type((address)&_regions,
59 ResourceObj::C_HEAP),
60 (int)max_size),
61 true),
62 _next_rr_candidate(0),
63 _seq_bottom(NULL)
64 {}
66 // Private methods.
68 HeapWord*
69 HeapRegionSeq::alloc_obj_from_region_index(int ind, size_t word_size) {
70 assert(G1CollectedHeap::isHumongous(word_size),
71 "Allocation size should be humongous");
72 int cur = ind;
73 int first = cur;
74 size_t sumSizes = 0;
75 while (cur < _regions.length() && sumSizes < word_size) {
76 // Loop invariant:
77 // For all i in [first, cur):
78 // _regions.at(i)->is_empty()
79 // && _regions.at(i) is contiguous with its predecessor, if any
80 // && sumSizes is the sum of the sizes of the regions in the interval
81 // [first, cur)
82 HeapRegion* curhr = _regions.at(cur);
83 if (curhr->is_empty()
84 && (first == cur
85 || (_regions.at(cur-1)->end() ==
86 curhr->bottom()))) {
87 sumSizes += curhr->capacity() / HeapWordSize;
88 } else {
89 first = cur + 1;
90 sumSizes = 0;
91 }
92 cur++;
93 }
94 if (sumSizes >= word_size) {
95 _alloc_search_start = cur;
97 // We need to initialize the region(s) we just discovered. This is
98 // a bit tricky given that it can happen concurrently with
99 // refinement threads refining cards on these regions and
100 // potentially wanting to refine the BOT as they are scanning
101 // those cards (this can happen shortly after a cleanup; see CR
102 // 6991377). So we have to set up the region(s) carefully and in
103 // a specific order.
105 // Currently, allocs_are_zero_filled() returns false. The zero
106 // filling infrastructure will be going away soon (see CR 6977804).
107 // So no need to do anything else here.
108 bool zf = G1CollectedHeap::heap()->allocs_are_zero_filled();
109 assert(!zf, "not supported");
111 // This will be the "starts humongous" region.
112 HeapRegion* first_hr = _regions.at(first);
113 {
114 MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
115 first_hr->set_zero_fill_allocated();
116 }
117 // The header of the new object will be placed at the bottom of
118 // the first region.
119 HeapWord* new_obj = first_hr->bottom();
120 // This will be the new end of the first region in the series that
121 // should also match the end of the last region in the seriers.
122 // (Note: sumSizes = "region size" x "number of regions we found").
123 HeapWord* new_end = new_obj + sumSizes;
124 // This will be the new top of the first region that will reflect
125 // this allocation.
126 HeapWord* new_top = new_obj + word_size;
128 // First, we need to zero the header of the space that we will be
129 // allocating. When we update top further down, some refinement
130 // threads might try to scan the region. By zeroing the header we
131 // ensure that any thread that will try to scan the region will
132 // come across the zero klass word and bail out.
133 //
134 // NOTE: It would not have been correct to have used
135 // CollectedHeap::fill_with_object() and make the space look like
136 // an int array. The thread that is doing the allocation will
137 // later update the object header to a potentially different array
138 // type and, for a very short period of time, the klass and length
139 // fields will be inconsistent. This could cause a refinement
140 // thread to calculate the object size incorrectly.
141 Copy::fill_to_words(new_obj, oopDesc::header_size(), 0);
143 // We will set up the first region as "starts humongous". This
144 // will also update the BOT covering all the regions to reflect
145 // that there is a single object that starts at the bottom of the
146 // first region.
147 first_hr->set_startsHumongous(new_end);
149 // Then, if there are any, we will set up the "continues
150 // humongous" regions.
151 HeapRegion* hr = NULL;
152 for (int i = first + 1; i < cur; ++i) {
153 hr = _regions.at(i);
154 {
155 MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
156 hr->set_zero_fill_allocated();
157 }
158 hr->set_continuesHumongous(first_hr);
159 }
160 // If we have "continues humongous" regions (hr != NULL), then the
161 // end of the last one should match new_end.
162 assert(hr == NULL || hr->end() == new_end, "sanity");
164 // Up to this point no concurrent thread would have been able to
165 // do any scanning on any region in this series. All the top
166 // fields still point to bottom, so the intersection between
167 // [bottom,top] and [card_start,card_end] will be empty. Before we
168 // update the top fields, we'll do a storestore to make sure that
169 // no thread sees the update to top before the zeroing of the
170 // object header and the BOT initialization.
171 OrderAccess::storestore();
173 // Now that the BOT and the object header have been initialized,
174 // we can update top of the "starts humongous" region.
175 assert(first_hr->bottom() < new_top && new_top <= first_hr->end(),
176 "new_top should be in this region");
177 first_hr->set_top(new_top);
179 // Now, we will update the top fields of the "continues humongous"
180 // regions. The reason we need to do this is that, otherwise,
181 // these regions would look empty and this will confuse parts of
182 // G1. For example, the code that looks for a consecutive number
183 // of empty regions will consider them empty and try to
184 // re-allocate them. We can extend is_empty() to also include
185 // !continuesHumongous(), but it is easier to just update the top
186 // fields here.
187 hr = NULL;
188 for (int i = first + 1; i < cur; ++i) {
189 hr = _regions.at(i);
190 if ((i + 1) == cur) {
191 // last continues humongous region
192 assert(hr->bottom() < new_top && new_top <= hr->end(),
193 "new_top should fall on this region");
194 hr->set_top(new_top);
195 } else {
196 // not last one
197 assert(new_top > hr->end(), "new_top should be above this region");
198 hr->set_top(hr->end());
199 }
200 }
201 // If we have continues humongous regions (hr != NULL), then the
202 // end of the last one should match new_end and its top should
203 // match new_top.
204 assert(hr == NULL ||
205 (hr->end() == new_end && hr->top() == new_top), "sanity");
207 return new_obj;
208 } else {
209 // If we started from the beginning, we want to know why we can't alloc.
210 return NULL;
211 }
212 }
214 void HeapRegionSeq::print_empty_runs() {
215 int empty_run = 0;
216 int n_empty = 0;
217 int empty_run_start;
218 for (int i = 0; i < _regions.length(); i++) {
219 HeapRegion* r = _regions.at(i);
220 if (r->continuesHumongous()) continue;
221 if (r->is_empty()) {
222 assert(!r->isHumongous(), "H regions should not be empty.");
223 if (empty_run == 0) empty_run_start = i;
224 empty_run++;
225 n_empty++;
226 } else {
227 if (empty_run > 0) {
228 gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
229 empty_run = 0;
230 }
231 }
232 }
233 if (empty_run > 0) {
234 gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
235 }
236 gclog_or_tty->print_cr(" [tot = %d]", n_empty);
237 }
239 int HeapRegionSeq::find(HeapRegion* hr) {
240 // FIXME: optimized for adjacent regions of fixed size.
241 int ind = hr->hrs_index();
242 if (ind != -1) {
243 assert(_regions.at(ind) == hr, "Mismatch");
244 }
245 return ind;
246 }
249 // Public methods.
251 void HeapRegionSeq::insert(HeapRegion* hr) {
252 assert(!_regions.is_full(), "Too many elements in HeapRegionSeq");
253 if (_regions.length() == 0
254 || _regions.top()->end() <= hr->bottom()) {
255 hr->set_hrs_index(_regions.length());
256 _regions.append(hr);
257 } else {
258 _regions.append(hr);
259 _regions.sort(orderRegions);
260 for (int i = 0; i < _regions.length(); i++) {
261 _regions.at(i)->set_hrs_index(i);
262 }
263 }
264 char* bot = (char*)_regions.at(0)->bottom();
265 if (_seq_bottom == NULL || bot < _seq_bottom) _seq_bottom = bot;
266 }
268 size_t HeapRegionSeq::length() {
269 return _regions.length();
270 }
272 size_t HeapRegionSeq::free_suffix() {
273 size_t res = 0;
274 int first = _regions.length() - 1;
275 int cur = first;
276 while (cur >= 0 &&
277 (_regions.at(cur)->is_empty()
278 && (first == cur
279 || (_regions.at(cur+1)->bottom() ==
280 _regions.at(cur)->end())))) {
281 res++;
282 cur--;
283 }
284 return res;
285 }
287 HeapWord* HeapRegionSeq::obj_allocate(size_t word_size) {
288 int cur = _alloc_search_start;
289 // Make sure "cur" is a valid index.
290 assert(cur >= 0, "Invariant.");
291 HeapWord* res = alloc_obj_from_region_index(cur, word_size);
292 if (res == NULL)
293 res = alloc_obj_from_region_index(0, word_size);
294 return res;
295 }
297 void HeapRegionSeq::iterate(HeapRegionClosure* blk) {
298 iterate_from((HeapRegion*)NULL, blk);
299 }
301 // The first argument r is the heap region at which iteration begins.
302 // This operation runs fastest when r is NULL, or the heap region for
303 // which a HeapRegionClosure most recently returned true, or the
304 // heap region immediately to its right in the sequence. In all
305 // other cases a linear search is required to find the index of r.
307 void HeapRegionSeq::iterate_from(HeapRegion* r, HeapRegionClosure* blk) {
309 // :::: FIXME ::::
310 // Static cache value is bad, especially when we start doing parallel
311 // remembered set update. For now just don't cache anything (the
312 // code in the def'd out blocks).
314 #if 0
315 static int cached_j = 0;
316 #endif
317 int len = _regions.length();
318 int j = 0;
319 // Find the index of r.
320 if (r != NULL) {
321 #if 0
322 assert(cached_j >= 0, "Invariant.");
323 if ((cached_j < len) && (r == _regions.at(cached_j))) {
324 j = cached_j;
325 } else if ((cached_j + 1 < len) && (r == _regions.at(cached_j + 1))) {
326 j = cached_j + 1;
327 } else {
328 j = find(r);
329 #endif
330 if (j < 0) {
331 j = 0;
332 }
333 #if 0
334 }
335 #endif
336 }
337 int i;
338 for (i = j; i < len; i += 1) {
339 int res = blk->doHeapRegion(_regions.at(i));
340 if (res) {
341 #if 0
342 cached_j = i;
343 #endif
344 blk->incomplete();
345 return;
346 }
347 }
348 for (i = 0; i < j; i += 1) {
349 int res = blk->doHeapRegion(_regions.at(i));
350 if (res) {
351 #if 0
352 cached_j = i;
353 #endif
354 blk->incomplete();
355 return;
356 }
357 }
358 }
360 void HeapRegionSeq::iterate_from(int idx, HeapRegionClosure* blk) {
361 int len = _regions.length();
362 int i;
363 for (i = idx; i < len; i++) {
364 if (blk->doHeapRegion(_regions.at(i))) {
365 blk->incomplete();
366 return;
367 }
368 }
369 for (i = 0; i < idx; i++) {
370 if (blk->doHeapRegion(_regions.at(i))) {
371 blk->incomplete();
372 return;
373 }
374 }
375 }
377 MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes,
378 size_t& num_regions_deleted) {
379 assert(shrink_bytes % os::vm_page_size() == 0, "unaligned");
380 assert(shrink_bytes % HeapRegion::GrainBytes == 0, "unaligned");
382 if (_regions.length() == 0) {
383 num_regions_deleted = 0;
384 return MemRegion();
385 }
386 int j = _regions.length() - 1;
387 HeapWord* end = _regions.at(j)->end();
388 HeapWord* last_start = end;
389 while (j >= 0 && shrink_bytes > 0) {
390 HeapRegion* cur = _regions.at(j);
391 // We have to leave humongous regions where they are,
392 // and work around them.
393 if (cur->isHumongous()) {
394 return MemRegion(last_start, end);
395 }
396 assert(cur == _regions.top(), "Should be top");
397 if (!cur->is_empty()) break;
398 cur->reset_zero_fill();
399 shrink_bytes -= cur->capacity();
400 num_regions_deleted++;
401 _regions.pop();
402 last_start = cur->bottom();
403 // We need to delete these somehow, but can't currently do so here: if
404 // we do, the ZF thread may still access the deleted region. We'll
405 // leave this here as a reminder that we have to do something about
406 // this.
407 // delete cur;
408 j--;
409 }
410 return MemRegion(last_start, end);
411 }
414 class PrintHeapRegionClosure : public HeapRegionClosure {
415 public:
416 bool doHeapRegion(HeapRegion* r) {
417 gclog_or_tty->print(PTR_FORMAT ":", r);
418 r->print();
419 return false;
420 }
421 };
423 void HeapRegionSeq::print() {
424 PrintHeapRegionClosure cl;
425 iterate(&cl);
426 }