Mercurial > hg > truffle
annotate src/share/vm/memory/heap.cpp @ 9408:c21b1e5b515c
Small refactoring
author | Christos Kotselidis <christos.kotselidis@oracle.com> |
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date | Sun, 28 Apr 2013 22:34:46 +0200 |
parents | 89e4d67fdd2a |
children | 836a62f43af9 |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. 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 * | |
1552
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "memory/heap.hpp" | |
27 #include "oops/oop.inline.hpp" | |
28 #include "runtime/os.hpp" | |
6197 | 29 #include "services/memTracker.hpp" |
0 | 30 |
31 size_t CodeHeap::header_size() { | |
32 return sizeof(HeapBlock); | |
33 } | |
34 | |
35 | |
36 // Implementation of Heap | |
37 | |
38 CodeHeap::CodeHeap() { | |
39 _number_of_committed_segments = 0; | |
40 _number_of_reserved_segments = 0; | |
41 _segment_size = 0; | |
42 _log2_segment_size = 0; | |
43 _next_segment = 0; | |
44 _freelist = NULL; | |
45 _free_segments = 0; | |
46 } | |
47 | |
48 | |
49 void CodeHeap::mark_segmap_as_free(size_t beg, size_t end) { | |
50 assert(0 <= beg && beg < _number_of_committed_segments, "interval begin out of bounds"); | |
51 assert(beg < end && end <= _number_of_committed_segments, "interval end out of bounds"); | |
52 // setup _segmap pointers for faster indexing | |
53 address p = (address)_segmap.low() + beg; | |
54 address q = (address)_segmap.low() + end; | |
55 // initialize interval | |
56 while (p < q) *p++ = 0xFF; | |
57 } | |
58 | |
59 | |
60 void CodeHeap::mark_segmap_as_used(size_t beg, size_t end) { | |
61 assert(0 <= beg && beg < _number_of_committed_segments, "interval begin out of bounds"); | |
62 assert(beg < end && end <= _number_of_committed_segments, "interval end out of bounds"); | |
63 // setup _segmap pointers for faster indexing | |
64 address p = (address)_segmap.low() + beg; | |
65 address q = (address)_segmap.low() + end; | |
66 // initialize interval | |
67 int i = 0; | |
68 while (p < q) { | |
69 *p++ = i++; | |
70 if (i == 0xFF) i = 1; | |
71 } | |
72 } | |
73 | |
74 | |
75 static size_t align_to_page_size(size_t size) { | |
76 const size_t alignment = (size_t)os::vm_page_size(); | |
77 assert(is_power_of_2(alignment), "no kidding ???"); | |
78 return (size + alignment - 1) & ~(alignment - 1); | |
79 } | |
80 | |
81 | |
82 void CodeHeap::on_code_mapping(char* base, size_t size) { | |
83 #ifdef LINUX | |
84 extern void linux_wrap_code(char* base, size_t size); | |
85 linux_wrap_code(base, size); | |
86 #endif | |
87 } | |
88 | |
89 | |
90 bool CodeHeap::reserve(size_t reserved_size, size_t committed_size, | |
91 size_t segment_size) { | |
92 assert(reserved_size >= committed_size, "reserved < committed"); | |
93 assert(segment_size >= sizeof(FreeBlock), "segment size is too small"); | |
94 assert(is_power_of_2(segment_size), "segment_size must be a power of 2"); | |
95 | |
96 _segment_size = segment_size; | |
97 _log2_segment_size = exact_log2(segment_size); | |
98 | |
99 // Reserve and initialize space for _memory. | |
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100 const size_t page_size = os::can_execute_large_page_memory() ? |
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101 os::page_size_for_region(committed_size, reserved_size, 8) : |
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102 os::vm_page_size(); |
0 | 103 const size_t granularity = os::vm_allocation_granularity(); |
104 const size_t r_align = MAX2(page_size, granularity); | |
105 const size_t r_size = align_size_up(reserved_size, r_align); | |
106 const size_t c_size = align_size_up(committed_size, page_size); | |
107 | |
108 const size_t rs_align = page_size == (size_t) os::vm_page_size() ? 0 : | |
109 MAX2(page_size, granularity); | |
656 | 110 ReservedCodeSpace rs(r_size, rs_align, rs_align > 0); |
0 | 111 os::trace_page_sizes("code heap", committed_size, reserved_size, page_size, |
112 rs.base(), rs.size()); | |
113 if (!_memory.initialize(rs, c_size)) { | |
114 return false; | |
115 } | |
116 | |
117 on_code_mapping(_memory.low(), _memory.committed_size()); | |
118 _number_of_committed_segments = number_of_segments(_memory.committed_size()); | |
119 _number_of_reserved_segments = number_of_segments(_memory.reserved_size()); | |
120 assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking"); | |
121 | |
122 // reserve space for _segmap | |
123 if (!_segmap.initialize(align_to_page_size(_number_of_reserved_segments), align_to_page_size(_number_of_committed_segments))) { | |
124 return false; | |
125 } | |
6197 | 126 |
127 MemTracker::record_virtual_memory_type((address)_segmap.low_boundary(), mtCode); | |
128 | |
0 | 129 assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "could not commit enough space for segment map"); |
130 assert(_segmap.reserved_size() >= (size_t) _number_of_reserved_segments , "could not reserve enough space for segment map"); | |
131 assert(_segmap.reserved_size() >= _segmap.committed_size() , "just checking"); | |
132 | |
133 // initialize remaining instance variables | |
134 clear(); | |
135 return true; | |
136 } | |
137 | |
138 | |
139 void CodeHeap::release() { | |
140 Unimplemented(); | |
141 } | |
142 | |
143 | |
144 bool CodeHeap::expand_by(size_t size) { | |
145 // expand _memory space | |
146 size_t dm = align_to_page_size(_memory.committed_size() + size) - _memory.committed_size(); | |
147 if (dm > 0) { | |
148 char* base = _memory.low() + _memory.committed_size(); | |
149 if (!_memory.expand_by(dm)) return false; | |
150 on_code_mapping(base, dm); | |
151 size_t i = _number_of_committed_segments; | |
152 _number_of_committed_segments = number_of_segments(_memory.committed_size()); | |
153 assert(_number_of_reserved_segments == number_of_segments(_memory.reserved_size()), "number of reserved segments should not change"); | |
154 assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking"); | |
155 // expand _segmap space | |
156 size_t ds = align_to_page_size(_number_of_committed_segments) - _segmap.committed_size(); | |
157 if (ds > 0) { | |
158 if (!_segmap.expand_by(ds)) return false; | |
159 } | |
160 assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "just checking"); | |
161 // initialize additional segmap entries | |
162 mark_segmap_as_free(i, _number_of_committed_segments); | |
163 } | |
164 return true; | |
165 } | |
166 | |
167 | |
168 void CodeHeap::shrink_by(size_t size) { | |
169 Unimplemented(); | |
170 } | |
171 | |
172 | |
173 void CodeHeap::clear() { | |
174 _next_segment = 0; | |
175 mark_segmap_as_free(0, _number_of_committed_segments); | |
176 } | |
177 | |
178 | |
179 void* CodeHeap::allocate(size_t size) { | |
180 size_t length = number_of_segments(size + sizeof(HeapBlock)); | |
181 assert(length *_segment_size >= sizeof(FreeBlock), "not enough room for FreeList"); | |
182 | |
183 // First check if we can satify request from freelist | |
184 debug_only(verify()); | |
185 HeapBlock* block = search_freelist(length); | |
186 debug_only(if (VerifyCodeCacheOften) verify()); | |
187 if (block != NULL) { | |
188 assert(block->length() >= length && block->length() < length + CodeCacheMinBlockLength, "sanity check"); | |
189 assert(!block->free(), "must be marked free"); | |
190 #ifdef ASSERT | |
191 memset((void *)block->allocated_space(), badCodeHeapNewVal, size); | |
192 #endif | |
193 return block->allocated_space(); | |
194 } | |
195 | |
196 if (length < CodeCacheMinBlockLength) { | |
197 length = CodeCacheMinBlockLength; | |
198 } | |
199 if (_next_segment + length <= _number_of_committed_segments) { | |
200 mark_segmap_as_used(_next_segment, _next_segment + length); | |
201 HeapBlock* b = block_at(_next_segment); | |
202 b->initialize(length); | |
203 _next_segment += length; | |
204 #ifdef ASSERT | |
205 memset((void *)b->allocated_space(), badCodeHeapNewVal, size); | |
206 #endif | |
207 return b->allocated_space(); | |
208 } else { | |
209 return NULL; | |
210 } | |
211 } | |
212 | |
213 | |
214 void CodeHeap::deallocate(void* p) { | |
215 assert(p == find_start(p), "illegal deallocation"); | |
216 // Find start of HeapBlock | |
217 HeapBlock* b = (((HeapBlock *)p) - 1); | |
218 assert(b->allocated_space() == p, "sanity check"); | |
219 #ifdef ASSERT | |
220 memset((void *)b->allocated_space(), | |
221 badCodeHeapFreeVal, | |
222 size(b->length()) - sizeof(HeapBlock)); | |
223 #endif | |
224 add_to_freelist(b); | |
225 | |
226 debug_only(if (VerifyCodeCacheOften) verify()); | |
227 } | |
228 | |
229 | |
230 void* CodeHeap::find_start(void* p) const { | |
231 if (!contains(p)) { | |
232 return NULL; | |
233 } | |
234 size_t i = segment_for(p); | |
235 address b = (address)_segmap.low(); | |
236 if (b[i] == 0xFF) { | |
237 return NULL; | |
238 } | |
239 while (b[i] > 0) i -= (int)b[i]; | |
240 HeapBlock* h = block_at(i); | |
241 if (h->free()) { | |
242 return NULL; | |
243 } | |
244 return h->allocated_space(); | |
245 } | |
246 | |
247 | |
248 size_t CodeHeap::alignment_unit() const { | |
249 // this will be a power of two | |
250 return _segment_size; | |
251 } | |
252 | |
253 | |
254 size_t CodeHeap::alignment_offset() const { | |
255 // The lowest address in any allocated block will be | |
256 // equal to alignment_offset (mod alignment_unit). | |
257 return sizeof(HeapBlock) & (_segment_size - 1); | |
258 } | |
259 | |
260 // Finds the next free heapblock. If the current one is free, that it returned | |
261 void* CodeHeap::next_free(HeapBlock *b) const { | |
262 // Since free blocks are merged, there is max. on free block | |
263 // between two used ones | |
264 if (b != NULL && b->free()) b = next_block(b); | |
265 assert(b == NULL || !b->free(), "must be in use or at end of heap"); | |
266 return (b == NULL) ? NULL : b->allocated_space(); | |
267 } | |
268 | |
269 // Returns the first used HeapBlock | |
270 HeapBlock* CodeHeap::first_block() const { | |
271 if (_next_segment > 0) | |
272 return block_at(0); | |
273 return NULL; | |
274 } | |
275 | |
276 HeapBlock *CodeHeap::block_start(void *q) const { | |
277 HeapBlock* b = (HeapBlock*)find_start(q); | |
278 if (b == NULL) return NULL; | |
279 return b - 1; | |
280 } | |
281 | |
282 // Returns the next Heap block an offset into one | |
283 HeapBlock* CodeHeap::next_block(HeapBlock *b) const { | |
284 if (b == NULL) return NULL; | |
285 size_t i = segment_for(b) + b->length(); | |
286 if (i < _next_segment) | |
287 return block_at(i); | |
288 return NULL; | |
289 } | |
290 | |
291 | |
292 // Returns current capacity | |
293 size_t CodeHeap::capacity() const { | |
294 return _memory.committed_size(); | |
295 } | |
296 | |
297 size_t CodeHeap::max_capacity() const { | |
298 return _memory.reserved_size(); | |
299 } | |
300 | |
301 size_t CodeHeap::allocated_capacity() const { | |
302 // Start with the committed size in _memory; | |
303 size_t l = _memory.committed_size(); | |
304 | |
305 // Subtract the committed, but unused, segments | |
306 l -= size(_number_of_committed_segments - _next_segment); | |
307 | |
308 // Subtract the size of the freelist | |
309 l -= size(_free_segments); | |
310 | |
311 return l; | |
312 } | |
313 | |
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314 size_t CodeHeap::largest_free_block() const { |
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315 // First check unused space excluding free blocks. |
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316 size_t free_sz = size(_free_segments); |
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317 size_t unused = max_capacity() - allocated_capacity() - free_sz; |
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318 if (unused >= free_sz) |
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319 return unused; |
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320 |
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321 // Now check largest free block. |
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322 size_t len = 0; |
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323 for (FreeBlock* b = _freelist; b != NULL; b = b->link()) { |
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324 if (b->length() > len) |
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325 len = b->length(); |
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326 } |
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327 return MAX2(unused, size(len)); |
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328 } |
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329 |
0 | 330 // Free list management |
331 | |
332 FreeBlock *CodeHeap::following_block(FreeBlock *b) { | |
333 return (FreeBlock*)(((address)b) + _segment_size * b->length()); | |
334 } | |
335 | |
336 // Inserts block b after a | |
337 void CodeHeap::insert_after(FreeBlock* a, FreeBlock* b) { | |
338 assert(a != NULL && b != NULL, "must be real pointers"); | |
339 | |
340 // Link b into the list after a | |
341 b->set_link(a->link()); | |
342 a->set_link(b); | |
343 | |
344 // See if we can merge blocks | |
345 merge_right(b); // Try to make b bigger | |
346 merge_right(a); // Try to make a include b | |
347 } | |
348 | |
349 // Try to merge this block with the following block | |
350 void CodeHeap::merge_right(FreeBlock *a) { | |
351 assert(a->free(), "must be a free block"); | |
352 if (following_block(a) == a->link()) { | |
353 assert(a->link() != NULL && a->link()->free(), "must be free too"); | |
354 // Update block a to include the following block | |
355 a->set_length(a->length() + a->link()->length()); | |
356 a->set_link(a->link()->link()); | |
357 // Update find_start map | |
358 size_t beg = segment_for(a); | |
359 mark_segmap_as_used(beg, beg + a->length()); | |
360 } | |
361 } | |
362 | |
363 void CodeHeap::add_to_freelist(HeapBlock *a) { | |
364 FreeBlock* b = (FreeBlock*)a; | |
365 assert(b != _freelist, "cannot be removed twice"); | |
366 | |
367 // Mark as free and update free space count | |
368 _free_segments += b->length(); | |
369 b->set_free(); | |
370 | |
371 // First element in list? | |
372 if (_freelist == NULL) { | |
373 _freelist = b; | |
374 b->set_link(NULL); | |
375 return; | |
376 } | |
377 | |
378 // Scan for right place to put into list. List | |
379 // is sorted by increasing addresseses | |
380 FreeBlock* prev = NULL; | |
381 FreeBlock* cur = _freelist; | |
382 while(cur != NULL && cur < b) { | |
383 assert(prev == NULL || prev < cur, "must be ordered"); | |
384 prev = cur; | |
385 cur = cur->link(); | |
386 } | |
387 | |
388 assert( (prev == NULL && b < _freelist) || | |
389 (prev < b && (cur == NULL || b < cur)), "list must be ordered"); | |
390 | |
391 if (prev == NULL) { | |
392 // Insert first in list | |
393 b->set_link(_freelist); | |
394 _freelist = b; | |
395 merge_right(_freelist); | |
396 } else { | |
397 insert_after(prev, b); | |
398 } | |
399 } | |
400 | |
401 // Search freelist for an entry on the list with the best fit | |
402 // Return NULL if no one was found | |
403 FreeBlock* CodeHeap::search_freelist(size_t length) { | |
404 FreeBlock *best_block = NULL; | |
405 FreeBlock *best_prev = NULL; | |
406 size_t best_length = 0; | |
407 | |
408 // Search for smallest block which is bigger than length | |
409 FreeBlock *prev = NULL; | |
410 FreeBlock *cur = _freelist; | |
411 while(cur != NULL) { | |
412 size_t l = cur->length(); | |
413 if (l >= length && (best_block == NULL || best_length > l)) { | |
414 // Remember best block, its previous element, and its length | |
415 best_block = cur; | |
416 best_prev = prev; | |
417 best_length = best_block->length(); | |
418 } | |
419 | |
420 // Next element in list | |
421 prev = cur; | |
422 cur = cur->link(); | |
423 } | |
424 | |
425 if (best_block == NULL) { | |
426 // None found | |
427 return NULL; | |
428 } | |
429 | |
430 assert((best_prev == NULL && _freelist == best_block ) || | |
431 (best_prev != NULL && best_prev->link() == best_block), "sanity check"); | |
432 | |
433 // Exact (or at least good enough) fit. Remove from list. | |
434 // Don't leave anything on the freelist smaller than CodeCacheMinBlockLength. | |
435 if (best_length < length + CodeCacheMinBlockLength) { | |
436 length = best_length; | |
437 if (best_prev == NULL) { | |
438 assert(_freelist == best_block, "sanity check"); | |
439 _freelist = _freelist->link(); | |
440 } else { | |
441 // Unmap element | |
442 best_prev->set_link(best_block->link()); | |
443 } | |
444 } else { | |
445 // Truncate block and return a pointer to the following block | |
446 best_block->set_length(best_length - length); | |
447 best_block = following_block(best_block); | |
448 // Set used bit and length on new block | |
449 size_t beg = segment_for(best_block); | |
450 mark_segmap_as_used(beg, beg + length); | |
451 best_block->set_length(length); | |
452 } | |
453 | |
454 best_block->set_used(); | |
455 _free_segments -= length; | |
456 return best_block; | |
457 } | |
458 | |
459 //---------------------------------------------------------------------------- | |
460 // Non-product code | |
461 | |
462 #ifndef PRODUCT | |
463 | |
464 void CodeHeap::print() { | |
465 tty->print_cr("The Heap"); | |
466 } | |
467 | |
468 #endif | |
469 | |
470 void CodeHeap::verify() { | |
471 // Count the number of blocks on the freelist, and the amount of space | |
472 // represented. | |
473 int count = 0; | |
474 size_t len = 0; | |
475 for(FreeBlock* b = _freelist; b != NULL; b = b->link()) { | |
476 len += b->length(); | |
477 count++; | |
478 } | |
479 | |
480 // Verify that freelist contains the right amount of free space | |
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481 // guarantee(len == _free_segments, "wrong freelist"); |
0 | 482 |
483 // Verify that the number of free blocks is not out of hand. | |
484 static int free_block_threshold = 10000; | |
485 if (count > free_block_threshold) { | |
486 warning("CodeHeap: # of free blocks > %d", free_block_threshold); | |
487 // Double the warning limit | |
488 free_block_threshold *= 2; | |
489 } | |
490 | |
491 // Verify that the freelist contains the same number of free blocks that is | |
492 // found on the full list. | |
493 for(HeapBlock *h = first_block(); h != NULL; h = next_block(h)) { | |
494 if (h->free()) count--; | |
495 } | |
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496 // guarantee(count == 0, "missing free blocks"); |
0 | 497 } |