1 /*
2 * Copyright (c) 2014, 2016, 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/markOop.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/bitMap.inline.hpp"
34
35 G1PageBasedVirtualSpace::G1PageBasedVirtualSpace(ReservedSpace rs, size_t used_size, size_t page_size) :
36 _low_boundary(NULL), _high_boundary(NULL), _committed(), _page_size(0), _special(false),
37 _dirty(), _executable(false) {
38 initialize_with_page_size(rs, used_size, page_size);
39 }
40
41 void G1PageBasedVirtualSpace::initialize_with_page_size(ReservedSpace rs, size_t used_size, size_t page_size) {
42 guarantee(rs.is_reserved(), "Given reserved space must have been reserved already.");
43
44 vmassert(_low_boundary == NULL, "VirtualSpace already initialized");
45 vmassert(page_size > 0, "Page size must be non-zero.");
46
47 guarantee(is_aligned(rs.base(), page_size),
48 "Reserved space base " PTR_FORMAT " is not aligned to requested page size " SIZE_FORMAT, p2i(rs.base()), page_size);
49 guarantee(is_aligned(used_size, os::vm_page_size()),
50 "Given used reserved space size needs to be OS page size aligned (%d bytes) but is " SIZE_FORMAT, os::vm_page_size(), used_size);
51 guarantee(used_size <= rs.size(),
52 "Used size of reserved space " SIZE_FORMAT " bytes is smaller than reservation at " SIZE_FORMAT " bytes", used_size, rs.size());
53 guarantee(is_aligned(rs.size(), page_size),
54 "Expected that the virtual space is size aligned, but " SIZE_FORMAT " is not aligned to page size " SIZE_FORMAT, rs.size(), page_size);
55
56 _low_boundary = rs.base();
57 _high_boundary = _low_boundary + used_size;
58
59 _special = rs.special();
60 _executable = rs.executable();
61
62 _page_size = page_size;
63
64 vmassert(_committed.size() == 0, "virtual space initialized more than once");
65 BitMap::idx_t size_in_pages = rs.size() / page_size;
66 _committed.initialize(size_in_pages);
67 if (_special) {
68 _dirty.initialize(size_in_pages);
69 }
70
71 _tail_size = used_size % _page_size;
72 }
73
74 G1PageBasedVirtualSpace::~G1PageBasedVirtualSpace() {
75 // This does not release memory it never reserved.
76 // Caller must release via rs.release();
77 _low_boundary = NULL;
78 _high_boundary = NULL;
79 _special = false;
80 _executable = false;
81 _page_size = 0;
82 _tail_size = 0;
83 }
84
85 size_t G1PageBasedVirtualSpace::committed_size() const {
86 size_t result = _committed.count_one_bits() * _page_size;
87 // The last page might not be in full.
88 if (is_last_page_partial() && _committed.at(_committed.size() - 1)) {
89 result -= _page_size - _tail_size;
90 }
91 return result;
92 }
93
94 size_t G1PageBasedVirtualSpace::reserved_size() const {
95 return pointer_delta(_high_boundary, _low_boundary, sizeof(char));
96 }
97
98 size_t G1PageBasedVirtualSpace::uncommitted_size() const {
99 return reserved_size() - committed_size();
100 }
101
102 size_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
103 return (addr - _low_boundary) / _page_size;
104 }
105
106 bool G1PageBasedVirtualSpace::is_area_committed(size_t start_page, size_t size_in_pages) const {
107 size_t end_page = start_page + size_in_pages;
108 return _committed.get_next_zero_offset(start_page, end_page) >= end_page;
109 }
110
111 bool G1PageBasedVirtualSpace::is_area_uncommitted(size_t start_page, size_t size_in_pages) const {
112 size_t end_page = start_page + size_in_pages;
113 return _committed.get_next_one_offset(start_page, end_page) >= end_page;
114 }
115
116 char* G1PageBasedVirtualSpace::page_start(size_t index) const {
117 return _low_boundary + index * _page_size;
118 }
119
120 bool G1PageBasedVirtualSpace::is_after_last_page(size_t index) const {
121 guarantee(index <= _committed.size(),
122 "Given boundary page " SIZE_FORMAT " is beyond managed page count " SIZE_FORMAT, index, _committed.size());
123 return index == _committed.size();
124 }
125
126 void G1PageBasedVirtualSpace::commit_preferred_pages(size_t start, size_t num_pages) {
127 vmassert(num_pages > 0, "No full pages to commit");
128 vmassert(start + num_pages <= _committed.size(),
129 "Tried to commit area from page " SIZE_FORMAT " to page " SIZE_FORMAT " "
130 "that is outside of managed space of " SIZE_FORMAT " pages",
131 start, start + num_pages, _committed.size());
132
133 char* start_addr = page_start(start);
134 size_t size = num_pages * _page_size;
135
136 os::commit_memory_or_exit(start_addr, size, _page_size, _executable,
137 err_msg("Failed to commit area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
138 p2i(start_addr), p2i(start_addr + size), size));
139 }
140
141 void G1PageBasedVirtualSpace::commit_tail() {
142 vmassert(_tail_size > 0, "The size of the tail area must be > 0 when reaching here");
143
144 char* const aligned_end_address = align_down(_high_boundary, _page_size);
145 os::commit_memory_or_exit(aligned_end_address, _tail_size, os::vm_page_size(), _executable,
146 err_msg("Failed to commit tail area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
147 p2i(aligned_end_address), p2i(_high_boundary), _tail_size));
148 }
149
150 void G1PageBasedVirtualSpace::commit_internal(size_t start_page, size_t end_page) {
151 guarantee(start_page < end_page,
152 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
153 guarantee(end_page <= _committed.size(),
154 "Given end page " SIZE_FORMAT " is beyond end of managed page amount of " SIZE_FORMAT, end_page, _committed.size());
155
156 size_t pages = end_page - start_page;
157 bool need_to_commit_tail = is_after_last_page(end_page) && is_last_page_partial();
158
159 // If we have to commit some (partial) tail area, decrease the amount of pages to avoid
160 // committing that in the full-page commit code.
161 if (need_to_commit_tail) {
162 pages--;
163 }
164
165 if (pages > 0) {
166 commit_preferred_pages(start_page, pages);
167 }
168
169 if (need_to_commit_tail) {
170 commit_tail();
171 }
172 }
173
174 char* G1PageBasedVirtualSpace::bounded_end_addr(size_t end_page) const {
175 return MIN2(_high_boundary, page_start(end_page));
176 }
177
178 void G1PageBasedVirtualSpace::pretouch_internal(size_t start_page, size_t end_page) {
179 guarantee(start_page < end_page,
180 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
181
182 os::pretouch_memory(page_start(start_page), bounded_end_addr(end_page), _page_size);
183 }
184
185 bool G1PageBasedVirtualSpace::commit(size_t start_page, size_t size_in_pages) {
186 // We need to make sure to commit all pages covered by the given area.
187 guarantee(is_area_uncommitted(start_page, size_in_pages), "Specified area is not uncommitted");
188
189 bool zero_filled = true;
190 size_t end_page = start_page + size_in_pages;
191
192 if (_special) {
193 // Check for dirty pages and update zero_filled if any found.
194 if (_dirty.get_next_one_offset(start_page, end_page) < end_page) {
195 zero_filled = false;
196 _dirty.clear_range(start_page, end_page);
197 }
198 } else {
199 commit_internal(start_page, end_page);
200 }
201 _committed.set_range(start_page, end_page);
202
203 return zero_filled;
204 }
205
206 void G1PageBasedVirtualSpace::uncommit_internal(size_t start_page, size_t end_page) {
207 guarantee(start_page < end_page,
208 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
209
210 char* start_addr = page_start(start_page);
211 os::uncommit_memory(start_addr, pointer_delta(bounded_end_addr(end_page), start_addr, sizeof(char)));
212 }
213
214 void G1PageBasedVirtualSpace::uncommit(size_t start_page, size_t size_in_pages) {
215 guarantee(is_area_committed(start_page, size_in_pages), "checking");
216
217 size_t end_page = start_page + size_in_pages;
218 if (_special) {
219 // Mark that memory is dirty. If committed again the memory might
220 // need to be cleared explicitly.
221 _dirty.set_range(start_page, end_page);
222 } else {
223 uncommit_internal(start_page, end_page);
224 }
225
226 _committed.clear_range(start_page, end_page);
227 }
228
229 class G1PretouchTask : public AbstractGangTask {
230 private:
231 char* volatile _cur_addr;
232 char* const _start_addr;
233 char* const _end_addr;
234 size_t const _page_size;
235 public:
236 G1PretouchTask(char* start_address, char* end_address, size_t page_size) :
237 AbstractGangTask("G1 PreTouch",
238 Universe::is_fully_initialized() &&
239 Thread::current()->is_Named_thread() ? GCId::current_raw() :
240 // During VM initialization there is
241 // no GC cycle that this task can be
242 // associated with.
243 GCId::undefined()),
244 _cur_addr(start_address),
245 _start_addr(start_address),
246 _end_addr(end_address),
247 _page_size(page_size) {
248 }
249
250 virtual void work(uint worker_id) {
251 size_t const actual_chunk_size = MAX2(chunk_size(), _page_size);
252 while (true) {
253 char* touch_addr = (char*)Atomic::add_ptr((intptr_t)actual_chunk_size, (volatile void*) &_cur_addr) - actual_chunk_size;
254 if (touch_addr < _start_addr || touch_addr >= _end_addr) {
255 break;
256 }
257 char* end_addr = touch_addr + MIN2(actual_chunk_size, pointer_delta(_end_addr, touch_addr, sizeof(char)));
258 os::pretouch_memory(touch_addr, end_addr, _page_size);
259 }
260 }
261
262 static size_t chunk_size() { return PreTouchParallelChunkSize; }
263 };
264
265 void G1PageBasedVirtualSpace::pretouch(size_t start_page, size_t size_in_pages, WorkGang* pretouch_gang) {
266 G1PretouchTask cl(page_start(start_page), bounded_end_addr(start_page + size_in_pages), _page_size);
267
268 if (pretouch_gang != NULL) {
269 size_t num_chunks = MAX2((size_t)1, size_in_pages * _page_size / MAX2(G1PretouchTask::chunk_size(), _page_size));
270
271 uint num_workers = MIN2((uint)num_chunks, pretouch_gang->active_workers());
272 log_debug(gc, heap)("Running %s with %u workers for " SIZE_FORMAT " work units pre-touching " SIZE_FORMAT "B.",
273 cl.name(), num_workers, num_chunks, size_in_pages * _page_size);
274 pretouch_gang->run_task(&cl, num_workers);
275 } else {
276 log_debug(gc, heap)("Running %s pre-touching " SIZE_FORMAT "B.",
277 cl.name(), size_in_pages * _page_size);
278 cl.work(0);
279 }
280 }
281
282 bool G1PageBasedVirtualSpace::contains(const void* p) const {
283 return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
284 }
285
286 #ifndef PRODUCT
287 void G1PageBasedVirtualSpace::print_on(outputStream* out) {
288 out->print ("Virtual space:");
289 if (_special) out->print(" (pinned in memory)");
290 out->cr();
291 out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
292 out->print_cr(" - reserved: " SIZE_FORMAT, reserved_size());
293 out->print_cr(" - preferred page size: " SIZE_FORMAT, _page_size);
294 out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]", p2i(_low_boundary), p2i(_high_boundary));
295 }
296
297 void G1PageBasedVirtualSpace::print() {
298 print_on(tty);
299 }
300 #endif