Fri, 07 Sep 2012 12:04:16 -0400
7195833: NPG: Rename instanceClassLoaderKlass, instanceRefKlass and instanceMirrorKlass
Summary: Simple renaming to be consistent with instanceKlass->InstanceKlass renaming
Reviewed-by: stefank, jmasa
1 /*
2 * Copyright (c) 1997, 2011, 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 */
25 #include "precompiled.hpp"
26 #include "memory/heap.hpp"
27 #include "oops/oop.inline.hpp"
28 #include "runtime/os.hpp"
29 #include "services/memTracker.hpp"
31 size_t CodeHeap::header_size() {
32 return sizeof(HeapBlock);
33 }
36 // Implementation of Heap
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 }
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 }
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 }
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 }
82 static size_t align_to_allocation_size(size_t size) {
83 const size_t alignment = (size_t)os::vm_allocation_granularity();
84 assert(is_power_of_2(alignment), "no kidding ???");
85 return (size + alignment - 1) & ~(alignment - 1);
86 }
89 void CodeHeap::on_code_mapping(char* base, size_t size) {
90 #ifdef LINUX
91 extern void linux_wrap_code(char* base, size_t size);
92 linux_wrap_code(base, size);
93 #endif
94 }
97 bool CodeHeap::reserve(size_t reserved_size, size_t committed_size,
98 size_t segment_size) {
99 assert(reserved_size >= committed_size, "reserved < committed");
100 assert(segment_size >= sizeof(FreeBlock), "segment size is too small");
101 assert(is_power_of_2(segment_size), "segment_size must be a power of 2");
103 _segment_size = segment_size;
104 _log2_segment_size = exact_log2(segment_size);
106 // Reserve and initialize space for _memory.
107 const size_t page_size = os::can_execute_large_page_memory() ?
108 os::page_size_for_region(committed_size, reserved_size, 8) :
109 os::vm_page_size();
110 const size_t granularity = os::vm_allocation_granularity();
111 const size_t r_align = MAX2(page_size, granularity);
112 const size_t r_size = align_size_up(reserved_size, r_align);
113 const size_t c_size = align_size_up(committed_size, page_size);
115 const size_t rs_align = page_size == (size_t) os::vm_page_size() ? 0 :
116 MAX2(page_size, granularity);
117 ReservedCodeSpace rs(r_size, rs_align, rs_align > 0);
118 os::trace_page_sizes("code heap", committed_size, reserved_size, page_size,
119 rs.base(), rs.size());
120 if (!_memory.initialize(rs, c_size)) {
121 return false;
122 }
124 on_code_mapping(_memory.low(), _memory.committed_size());
125 _number_of_committed_segments = number_of_segments(_memory.committed_size());
126 _number_of_reserved_segments = number_of_segments(_memory.reserved_size());
127 assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking");
129 // reserve space for _segmap
130 if (!_segmap.initialize(align_to_page_size(_number_of_reserved_segments), align_to_page_size(_number_of_committed_segments))) {
131 return false;
132 }
134 MemTracker::record_virtual_memory_type((address)_segmap.low_boundary(), mtCode);
136 assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "could not commit enough space for segment map");
137 assert(_segmap.reserved_size() >= (size_t) _number_of_reserved_segments , "could not reserve enough space for segment map");
138 assert(_segmap.reserved_size() >= _segmap.committed_size() , "just checking");
140 // initialize remaining instance variables
141 clear();
142 return true;
143 }
146 void CodeHeap::release() {
147 Unimplemented();
148 }
151 bool CodeHeap::expand_by(size_t size) {
152 // expand _memory space
153 size_t dm = align_to_page_size(_memory.committed_size() + size) - _memory.committed_size();
154 if (dm > 0) {
155 char* base = _memory.low() + _memory.committed_size();
156 if (!_memory.expand_by(dm)) return false;
157 on_code_mapping(base, dm);
158 size_t i = _number_of_committed_segments;
159 _number_of_committed_segments = number_of_segments(_memory.committed_size());
160 assert(_number_of_reserved_segments == number_of_segments(_memory.reserved_size()), "number of reserved segments should not change");
161 assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking");
162 // expand _segmap space
163 size_t ds = align_to_page_size(_number_of_committed_segments) - _segmap.committed_size();
164 if (ds > 0) {
165 if (!_segmap.expand_by(ds)) return false;
166 }
167 assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "just checking");
168 // initialize additional segmap entries
169 mark_segmap_as_free(i, _number_of_committed_segments);
170 }
171 return true;
172 }
175 void CodeHeap::shrink_by(size_t size) {
176 Unimplemented();
177 }
180 void CodeHeap::clear() {
181 _next_segment = 0;
182 mark_segmap_as_free(0, _number_of_committed_segments);
183 }
186 void* CodeHeap::allocate(size_t size) {
187 size_t length = number_of_segments(size + sizeof(HeapBlock));
188 assert(length *_segment_size >= sizeof(FreeBlock), "not enough room for FreeList");
190 // First check if we can satify request from freelist
191 debug_only(verify());
192 HeapBlock* block = search_freelist(length);
193 debug_only(if (VerifyCodeCacheOften) verify());
194 if (block != NULL) {
195 assert(block->length() >= length && block->length() < length + CodeCacheMinBlockLength, "sanity check");
196 assert(!block->free(), "must be marked free");
197 #ifdef ASSERT
198 memset((void *)block->allocated_space(), badCodeHeapNewVal, size);
199 #endif
200 return block->allocated_space();
201 }
203 if (length < CodeCacheMinBlockLength) {
204 length = CodeCacheMinBlockLength;
205 }
206 if (_next_segment + length <= _number_of_committed_segments) {
207 mark_segmap_as_used(_next_segment, _next_segment + length);
208 HeapBlock* b = block_at(_next_segment);
209 b->initialize(length);
210 _next_segment += length;
211 #ifdef ASSERT
212 memset((void *)b->allocated_space(), badCodeHeapNewVal, size);
213 #endif
214 return b->allocated_space();
215 } else {
216 return NULL;
217 }
218 }
221 void CodeHeap::deallocate(void* p) {
222 assert(p == find_start(p), "illegal deallocation");
223 // Find start of HeapBlock
224 HeapBlock* b = (((HeapBlock *)p) - 1);
225 assert(b->allocated_space() == p, "sanity check");
226 #ifdef ASSERT
227 memset((void *)b->allocated_space(),
228 badCodeHeapFreeVal,
229 size(b->length()) - sizeof(HeapBlock));
230 #endif
231 add_to_freelist(b);
233 debug_only(if (VerifyCodeCacheOften) verify());
234 }
237 void* CodeHeap::find_start(void* p) const {
238 if (!contains(p)) {
239 return NULL;
240 }
241 size_t i = segment_for(p);
242 address b = (address)_segmap.low();
243 if (b[i] == 0xFF) {
244 return NULL;
245 }
246 while (b[i] > 0) i -= (int)b[i];
247 HeapBlock* h = block_at(i);
248 if (h->free()) {
249 return NULL;
250 }
251 return h->allocated_space();
252 }
255 size_t CodeHeap::alignment_unit() const {
256 // this will be a power of two
257 return _segment_size;
258 }
261 size_t CodeHeap::alignment_offset() const {
262 // The lowest address in any allocated block will be
263 // equal to alignment_offset (mod alignment_unit).
264 return sizeof(HeapBlock) & (_segment_size - 1);
265 }
267 // Finds the next free heapblock. If the current one is free, that it returned
268 void* CodeHeap::next_free(HeapBlock *b) const {
269 // Since free blocks are merged, there is max. on free block
270 // between two used ones
271 if (b != NULL && b->free()) b = next_block(b);
272 assert(b == NULL || !b->free(), "must be in use or at end of heap");
273 return (b == NULL) ? NULL : b->allocated_space();
274 }
276 // Returns the first used HeapBlock
277 HeapBlock* CodeHeap::first_block() const {
278 if (_next_segment > 0)
279 return block_at(0);
280 return NULL;
281 }
283 HeapBlock *CodeHeap::block_start(void *q) const {
284 HeapBlock* b = (HeapBlock*)find_start(q);
285 if (b == NULL) return NULL;
286 return b - 1;
287 }
289 // Returns the next Heap block an offset into one
290 HeapBlock* CodeHeap::next_block(HeapBlock *b) const {
291 if (b == NULL) return NULL;
292 size_t i = segment_for(b) + b->length();
293 if (i < _next_segment)
294 return block_at(i);
295 return NULL;
296 }
299 // Returns current capacity
300 size_t CodeHeap::capacity() const {
301 return _memory.committed_size();
302 }
304 size_t CodeHeap::max_capacity() const {
305 return _memory.reserved_size();
306 }
308 size_t CodeHeap::allocated_capacity() const {
309 // Start with the committed size in _memory;
310 size_t l = _memory.committed_size();
312 // Subtract the committed, but unused, segments
313 l -= size(_number_of_committed_segments - _next_segment);
315 // Subtract the size of the freelist
316 l -= size(_free_segments);
318 return l;
319 }
321 size_t CodeHeap::largest_free_block() const {
322 // First check unused space excluding free blocks.
323 size_t free_sz = size(_free_segments);
324 size_t unused = max_capacity() - allocated_capacity() - free_sz;
325 if (unused >= free_sz)
326 return unused;
328 // Now check largest free block.
329 size_t len = 0;
330 for (FreeBlock* b = _freelist; b != NULL; b = b->link()) {
331 if (b->length() > len)
332 len = b->length();
333 }
334 return MAX2(unused, size(len));
335 }
337 // Free list management
339 FreeBlock *CodeHeap::following_block(FreeBlock *b) {
340 return (FreeBlock*)(((address)b) + _segment_size * b->length());
341 }
343 // Inserts block b after a
344 void CodeHeap::insert_after(FreeBlock* a, FreeBlock* b) {
345 assert(a != NULL && b != NULL, "must be real pointers");
347 // Link b into the list after a
348 b->set_link(a->link());
349 a->set_link(b);
351 // See if we can merge blocks
352 merge_right(b); // Try to make b bigger
353 merge_right(a); // Try to make a include b
354 }
356 // Try to merge this block with the following block
357 void CodeHeap::merge_right(FreeBlock *a) {
358 assert(a->free(), "must be a free block");
359 if (following_block(a) == a->link()) {
360 assert(a->link() != NULL && a->link()->free(), "must be free too");
361 // Update block a to include the following block
362 a->set_length(a->length() + a->link()->length());
363 a->set_link(a->link()->link());
364 // Update find_start map
365 size_t beg = segment_for(a);
366 mark_segmap_as_used(beg, beg + a->length());
367 }
368 }
370 void CodeHeap::add_to_freelist(HeapBlock *a) {
371 FreeBlock* b = (FreeBlock*)a;
372 assert(b != _freelist, "cannot be removed twice");
374 // Mark as free and update free space count
375 _free_segments += b->length();
376 b->set_free();
378 // First element in list?
379 if (_freelist == NULL) {
380 _freelist = b;
381 b->set_link(NULL);
382 return;
383 }
385 // Scan for right place to put into list. List
386 // is sorted by increasing addresseses
387 FreeBlock* prev = NULL;
388 FreeBlock* cur = _freelist;
389 while(cur != NULL && cur < b) {
390 assert(prev == NULL || prev < cur, "must be ordered");
391 prev = cur;
392 cur = cur->link();
393 }
395 assert( (prev == NULL && b < _freelist) ||
396 (prev < b && (cur == NULL || b < cur)), "list must be ordered");
398 if (prev == NULL) {
399 // Insert first in list
400 b->set_link(_freelist);
401 _freelist = b;
402 merge_right(_freelist);
403 } else {
404 insert_after(prev, b);
405 }
406 }
408 // Search freelist for an entry on the list with the best fit
409 // Return NULL if no one was found
410 FreeBlock* CodeHeap::search_freelist(size_t length) {
411 FreeBlock *best_block = NULL;
412 FreeBlock *best_prev = NULL;
413 size_t best_length = 0;
415 // Search for smallest block which is bigger than length
416 FreeBlock *prev = NULL;
417 FreeBlock *cur = _freelist;
418 while(cur != NULL) {
419 size_t l = cur->length();
420 if (l >= length && (best_block == NULL || best_length > l)) {
421 // Remember best block, its previous element, and its length
422 best_block = cur;
423 best_prev = prev;
424 best_length = best_block->length();
425 }
427 // Next element in list
428 prev = cur;
429 cur = cur->link();
430 }
432 if (best_block == NULL) {
433 // None found
434 return NULL;
435 }
437 assert((best_prev == NULL && _freelist == best_block ) ||
438 (best_prev != NULL && best_prev->link() == best_block), "sanity check");
440 // Exact (or at least good enough) fit. Remove from list.
441 // Don't leave anything on the freelist smaller than CodeCacheMinBlockLength.
442 if (best_length < length + CodeCacheMinBlockLength) {
443 length = best_length;
444 if (best_prev == NULL) {
445 assert(_freelist == best_block, "sanity check");
446 _freelist = _freelist->link();
447 } else {
448 // Unmap element
449 best_prev->set_link(best_block->link());
450 }
451 } else {
452 // Truncate block and return a pointer to the following block
453 best_block->set_length(best_length - length);
454 best_block = following_block(best_block);
455 // Set used bit and length on new block
456 size_t beg = segment_for(best_block);
457 mark_segmap_as_used(beg, beg + length);
458 best_block->set_length(length);
459 }
461 best_block->set_used();
462 _free_segments -= length;
463 return best_block;
464 }
466 //----------------------------------------------------------------------------
467 // Non-product code
469 #ifndef PRODUCT
471 void CodeHeap::print() {
472 tty->print_cr("The Heap");
473 }
475 #endif
477 void CodeHeap::verify() {
478 // Count the number of blocks on the freelist, and the amount of space
479 // represented.
480 int count = 0;
481 size_t len = 0;
482 for(FreeBlock* b = _freelist; b != NULL; b = b->link()) {
483 len += b->length();
484 count++;
485 }
487 // Verify that freelist contains the right amount of free space
488 // guarantee(len == _free_segments, "wrong freelist");
490 // Verify that the number of free blocks is not out of hand.
491 static int free_block_threshold = 10000;
492 if (count > free_block_threshold) {
493 warning("CodeHeap: # of free blocks > %d", free_block_threshold);
494 // Double the warning limit
495 free_block_threshold *= 2;
496 }
498 // Verify that the freelist contains the same number of free blocks that is
499 // found on the full list.
500 for(HeapBlock *h = first_block(); h != NULL; h = next_block(h)) {
501 if (h->free()) count--;
502 }
503 // guarantee(count == 0, "missing free blocks");
504 }