Thu, 04 Apr 2013 10:01:26 -0700
8003310: Enable -Wunused-function when compiling with gcc
Summary: Add the -Wunused-function flag and remove a number of unused functions.
Reviewed-by: dholmes, coleenp, kvn
1 /*
2 * Copyright (c) 1997, 2012, 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 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 }
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");
96 _segment_size = segment_size;
97 _log2_segment_size = exact_log2(segment_size);
99 // Reserve and initialize space for _memory.
100 const size_t page_size = os::can_execute_large_page_memory() ?
101 os::page_size_for_region(committed_size, reserved_size, 8) :
102 os::vm_page_size();
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);
108 const size_t rs_align = page_size == (size_t) os::vm_page_size() ? 0 :
109 MAX2(page_size, granularity);
110 ReservedCodeSpace rs(r_size, rs_align, rs_align > 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 }
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");
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 }
127 MemTracker::record_virtual_memory_type((address)_segmap.low_boundary(), mtCode);
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");
133 // initialize remaining instance variables
134 clear();
135 return true;
136 }
139 void CodeHeap::release() {
140 Unimplemented();
141 }
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 }
168 void CodeHeap::shrink_by(size_t size) {
169 Unimplemented();
170 }
173 void CodeHeap::clear() {
174 _next_segment = 0;
175 mark_segmap_as_free(0, _number_of_committed_segments);
176 }
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");
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 }
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 }
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);
226 debug_only(if (VerifyCodeCacheOften) verify());
227 }
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 }
248 size_t CodeHeap::alignment_unit() const {
249 // this will be a power of two
250 return _segment_size;
251 }
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 }
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 }
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 }
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 }
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 }
292 // Returns current capacity
293 size_t CodeHeap::capacity() const {
294 return _memory.committed_size();
295 }
297 size_t CodeHeap::max_capacity() const {
298 return _memory.reserved_size();
299 }
301 size_t CodeHeap::allocated_capacity() const {
302 // Start with the committed size in _memory;
303 size_t l = _memory.committed_size();
305 // Subtract the committed, but unused, segments
306 l -= size(_number_of_committed_segments - _next_segment);
308 // Subtract the size of the freelist
309 l -= size(_free_segments);
311 return l;
312 }
314 size_t CodeHeap::largest_free_block() const {
315 // First check unused space excluding free blocks.
316 size_t free_sz = size(_free_segments);
317 size_t unused = max_capacity() - allocated_capacity() - free_sz;
318 if (unused >= free_sz)
319 return unused;
321 // Now check largest free block.
322 size_t len = 0;
323 for (FreeBlock* b = _freelist; b != NULL; b = b->link()) {
324 if (b->length() > len)
325 len = b->length();
326 }
327 return MAX2(unused, size(len));
328 }
330 // Free list management
332 FreeBlock *CodeHeap::following_block(FreeBlock *b) {
333 return (FreeBlock*)(((address)b) + _segment_size * b->length());
334 }
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");
340 // Link b into the list after a
341 b->set_link(a->link());
342 a->set_link(b);
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 }
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 }
363 void CodeHeap::add_to_freelist(HeapBlock *a) {
364 FreeBlock* b = (FreeBlock*)a;
365 assert(b != _freelist, "cannot be removed twice");
367 // Mark as free and update free space count
368 _free_segments += b->length();
369 b->set_free();
371 // First element in list?
372 if (_freelist == NULL) {
373 _freelist = b;
374 b->set_link(NULL);
375 return;
376 }
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 }
388 assert( (prev == NULL && b < _freelist) ||
389 (prev < b && (cur == NULL || b < cur)), "list must be ordered");
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 }
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;
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 }
420 // Next element in list
421 prev = cur;
422 cur = cur->link();
423 }
425 if (best_block == NULL) {
426 // None found
427 return NULL;
428 }
430 assert((best_prev == NULL && _freelist == best_block ) ||
431 (best_prev != NULL && best_prev->link() == best_block), "sanity check");
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 }
454 best_block->set_used();
455 _free_segments -= length;
456 return best_block;
457 }
459 //----------------------------------------------------------------------------
460 // Non-product code
462 #ifndef PRODUCT
464 void CodeHeap::print() {
465 tty->print_cr("The Heap");
466 }
468 #endif
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 }
480 // Verify that freelist contains the right amount of free space
481 // guarantee(len == _free_segments, "wrong freelist");
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 }
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 }
496 // guarantee(count == 0, "missing free blocks");
497 }