1 /*
2 * Copyright (c) 2014, 2018, 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 */
24
25 #include "precompiled.hpp"
26 #include "gc/g1/g1PageBasedVirtualSpace.hpp"
27 #include "gc/shared/workgroup.hpp"
28 #include "oops/markWord.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/atomic.hpp"
31 #include "runtime/os.inline.hpp"
32 #include "services/memTracker.hpp"
33 #include "utilities/align.hpp"
34 #include "utilities/bitMap.inline.hpp"
35
36 G1PageBasedVirtualSpace::G1PageBasedVirtualSpace(ReservedSpace rs, size_t used_size, size_t page_size) :
37 _low_boundary(NULL), _high_boundary(NULL), _tail_size(0), _page_size(0),
38 _committed(mtGC), _dirty(mtGC), _special(false), _executable(false) {
39 initialize_with_page_size(rs, used_size, page_size);
40 }
41
42 void G1PageBasedVirtualSpace::initialize_with_page_size(ReservedSpace rs, size_t used_size, size_t page_size) {
43 guarantee(rs.is_reserved(), "Given reserved space must have been reserved already.");
44
45 vmassert(_low_boundary == NULL, "VirtualSpace already initialized");
46 vmassert(page_size > 0, "Page size must be non-zero.");
47
48 guarantee(is_aligned(rs.base(), page_size),
49 "Reserved space base " PTR_FORMAT " is not aligned to requested page size " SIZE_FORMAT, p2i(rs.base()), page_size);
50 guarantee(is_aligned(used_size, os::vm_page_size()),
51 "Given used reserved space size needs to be OS page size aligned (%d bytes) but is " SIZE_FORMAT, os::vm_page_size(), used_size);
52 guarantee(used_size <= rs.size(),
53 "Used size of reserved space " SIZE_FORMAT " bytes is smaller than reservation at " SIZE_FORMAT " bytes", used_size, rs.size());
54 guarantee(is_aligned(rs.size(), page_size),
55 "Expected that the virtual space is size aligned, but " SIZE_FORMAT " is not aligned to page size " SIZE_FORMAT, rs.size(), page_size);
56
57 _low_boundary = rs.base();
58 _high_boundary = _low_boundary + used_size;
59
60 _special = rs.special();
61 _executable = rs.executable();
62
63 _page_size = page_size;
64
65 vmassert(_committed.size() == 0, "virtual space initialized more than once");
66 BitMap::idx_t size_in_pages = rs.size() / page_size;
67 _committed.initialize(size_in_pages);
68 if (_special) {
69 _dirty.initialize(size_in_pages);
70 }
71
72 _tail_size = used_size % _page_size;
73 }
74
75 G1PageBasedVirtualSpace::~G1PageBasedVirtualSpace() {
76 // This does not release memory it never reserved.
77 // Caller must release via rs.release();
78 _low_boundary = NULL;
79 _high_boundary = NULL;
80 _special = false;
81 _executable = false;
82 _page_size = 0;
83 _tail_size = 0;
84 }
85
86 size_t G1PageBasedVirtualSpace::committed_size() const {
87 size_t result = _committed.count_one_bits() * _page_size;
88 // The last page might not be in full.
89 if (is_last_page_partial() && _committed.at(_committed.size() - 1)) {
90 result -= _page_size - _tail_size;
91 }
92 return result;
93 }
94
95 size_t G1PageBasedVirtualSpace::reserved_size() const {
96 return pointer_delta(_high_boundary, _low_boundary, sizeof(char));
97 }
98
99 size_t G1PageBasedVirtualSpace::uncommitted_size() const {
100 return reserved_size() - committed_size();
101 }
102
103 void G1PageBasedVirtualSpace::commit_and_set_special() {
104 commit_internal(addr_to_page_index(_low_boundary), addr_to_page_index(_high_boundary));
105 _special = true;
106 _dirty.initialize(reserved_size()/_page_size);
107 }
108
109 size_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
110 return (addr - _low_boundary) / _page_size;
111 }
112
113 bool G1PageBasedVirtualSpace::is_area_committed(size_t start_page, size_t size_in_pages) const {
114 size_t end_page = start_page + size_in_pages;
115 return _committed.get_next_zero_offset(start_page, end_page) >= end_page;
116 }
117
118 bool G1PageBasedVirtualSpace::is_area_uncommitted(size_t start_page, size_t size_in_pages) const {
119 size_t end_page = start_page + size_in_pages;
120 return _committed.get_next_one_offset(start_page, end_page) >= end_page;
121 }
122
123 char* G1PageBasedVirtualSpace::page_start(size_t index) const {
124 return _low_boundary + index * _page_size;
125 }
126
127 size_t G1PageBasedVirtualSpace::page_size() const {
128 assert(_page_size > 0, "Page size is not yet initialized.");
129 return _page_size;
130 }
131
132 bool G1PageBasedVirtualSpace::is_after_last_page(size_t index) const {
133 guarantee(index <= _committed.size(),
134 "Given boundary page " SIZE_FORMAT " is beyond managed page count " SIZE_FORMAT, index, _committed.size());
135 return index == _committed.size();
136 }
137
138 void G1PageBasedVirtualSpace::commit_preferred_pages(size_t start, size_t num_pages) {
139 vmassert(num_pages > 0, "No full pages to commit");
140 vmassert(start + num_pages <= _committed.size(),
141 "Tried to commit area from page " SIZE_FORMAT " to page " SIZE_FORMAT " "
142 "that is outside of managed space of " SIZE_FORMAT " pages",
143 start, start + num_pages, _committed.size());
144
145 char* start_addr = page_start(start);
146 size_t size = num_pages * _page_size;
147
148 os::commit_memory_or_exit(start_addr, size, _page_size, _executable,
149 err_msg("Failed to commit area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
150 p2i(start_addr), p2i(start_addr + size), size));
151 }
152
153 void G1PageBasedVirtualSpace::commit_tail() {
154 vmassert(_tail_size > 0, "The size of the tail area must be > 0 when reaching here");
155
156 char* const aligned_end_address = align_down(_high_boundary, _page_size);
157 os::commit_memory_or_exit(aligned_end_address, _tail_size, os::vm_page_size(), _executable,
158 err_msg("Failed to commit tail area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
159 p2i(aligned_end_address), p2i(_high_boundary), _tail_size));
160 }
161
162 void G1PageBasedVirtualSpace::commit_internal(size_t start_page, size_t end_page) {
163 guarantee(start_page < end_page,
164 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
165 guarantee(end_page <= _committed.size(),
166 "Given end page " SIZE_FORMAT " is beyond end of managed page amount of " SIZE_FORMAT, end_page, _committed.size());
167
168 size_t pages = end_page - start_page;
169 bool need_to_commit_tail = is_after_last_page(end_page) && is_last_page_partial();
170
171 // If we have to commit some (partial) tail area, decrease the amount of pages to avoid
172 // committing that in the full-page commit code.
173 if (need_to_commit_tail) {
174 pages--;
175 }
176
177 if (pages > 0) {
178 commit_preferred_pages(start_page, pages);
179 }
180
181 if (need_to_commit_tail) {
182 commit_tail();
183 }
184 }
185
186 char* G1PageBasedVirtualSpace::bounded_end_addr(size_t end_page) const {
187 return MIN2(_high_boundary, page_start(end_page));
188 }
189
190 void G1PageBasedVirtualSpace::pretouch_internal(size_t start_page, size_t end_page) {
191 guarantee(start_page < end_page,
192 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
193
194 os::pretouch_memory(page_start(start_page), bounded_end_addr(end_page), _page_size);
195 }
196
197 bool G1PageBasedVirtualSpace::commit(size_t start_page, size_t size_in_pages) {
198 // We need to make sure to commit all pages covered by the given area.
199 guarantee(is_area_uncommitted(start_page, size_in_pages), "Specified area is not uncommitted");
200
201 bool zero_filled = true;
202 size_t end_page = start_page + size_in_pages;
203
204 if (_special) {
205 // Check for dirty pages and update zero_filled if any found.
206 if (_dirty.get_next_one_offset(start_page, end_page) < end_page) {
207 zero_filled = false;
208 _dirty.clear_range(start_page, end_page);
209 }
210 } else {
211 commit_internal(start_page, end_page);
212 }
213 _committed.par_set_range(start_page, end_page, BitMap::unknown_range);
214
215 return zero_filled;
216 }
217
218 void G1PageBasedVirtualSpace::uncommit_internal(size_t start_page, size_t end_page) {
219 guarantee(start_page < end_page,
220 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
221
222 char* start_addr = page_start(start_page);
223 os::uncommit_memory(start_addr, pointer_delta(bounded_end_addr(end_page), start_addr, sizeof(char)));
224 }
225
226 void G1PageBasedVirtualSpace::uncommit(size_t start_page, size_t size_in_pages) {
227 guarantee(is_area_committed(start_page, size_in_pages), "checking");
228
229 size_t end_page = start_page + size_in_pages;
230 if (_special) {
231 // Mark that memory is dirty. If committed again the memory might
232 // need to be cleared explicitly.
233 _dirty.set_range(start_page, end_page);
234 } else {
235 uncommit_internal(start_page, end_page);
236 }
237
238 _committed.par_clear_range(start_page, end_page, BitMap::unknown_range);
239 }
240
241 class G1PretouchTask : public AbstractGangTask {
242 private:
243 char* volatile _cur_addr;
244 char* const _start_addr;
245 char* const _end_addr;
246 size_t _page_size;
247 public:
248 G1PretouchTask(char* start_address, char* end_address, size_t page_size) :
249 AbstractGangTask("G1 PreTouch"),
250 _cur_addr(start_address),
251 _start_addr(start_address),
252 _end_addr(end_address),
253 _page_size(0) {
254 #ifdef LINUX
255 _page_size = UseTransparentHugePages ? (size_t)os::vm_page_size(): page_size;
256 #else
257 _page_size = page_size;
258 #endif
259 }
260
261 virtual void work(uint worker_id) {
262 size_t const actual_chunk_size = MAX2(chunk_size(), _page_size);
263 while (true) {
264 char* touch_addr = Atomic::add(&_cur_addr, actual_chunk_size) - actual_chunk_size;
265 if (touch_addr < _start_addr || touch_addr >= _end_addr) {
266 break;
267 }
268 char* end_addr = touch_addr + MIN2(actual_chunk_size, pointer_delta(_end_addr, touch_addr, sizeof(char)));
269 os::pretouch_memory(touch_addr, end_addr, _page_size);
270 }
271 }
272
273 static size_t chunk_size() { return PreTouchParallelChunkSize; }
274 };
275
276 void G1PageBasedVirtualSpace::pretouch(size_t start_page, size_t size_in_pages, WorkGang* pretouch_gang) {
277 G1PretouchTask cl(page_start(start_page), bounded_end_addr(start_page + size_in_pages), _page_size);
278
279 if (pretouch_gang != NULL) {
280 size_t num_chunks = MAX2((size_t)1, size_in_pages * _page_size / MAX2(G1PretouchTask::chunk_size(), _page_size));
281
282 uint num_workers = MIN2((uint)num_chunks, pretouch_gang->total_workers());
283 log_debug(gc, heap)("Running %s with %u workers for " SIZE_FORMAT " work units pre-touching " SIZE_FORMAT "B.",
284 cl.name(), num_workers, num_chunks, size_in_pages * _page_size);
285 pretouch_gang->run_task(&cl, num_workers);
286 } else {
287 log_debug(gc, heap)("Running %s pre-touching " SIZE_FORMAT "B.",
288 cl.name(), size_in_pages * _page_size);
289 cl.work(0);
290 }
291 }
292
293 bool G1PageBasedVirtualSpace::contains(const void* p) const {
294 return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
295 }
296
297 #ifndef PRODUCT
298 void G1PageBasedVirtualSpace::print_on(outputStream* out) {
299 out->print ("Virtual space:");
300 if (_special) out->print(" (pinned in memory)");
301 out->cr();
302 out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
303 out->print_cr(" - reserved: " SIZE_FORMAT, reserved_size());
304 out->print_cr(" - preferred page size: " SIZE_FORMAT, _page_size);
305 out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]", p2i(_low_boundary), p2i(_high_boundary));
306 }
307
308 void G1PageBasedVirtualSpace::print() {
309 print_on(tty);
310 }
311 #endif