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.
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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/align.hpp"
34#include "utilities/bitMap.inline.hpp"
35
36G1PageBasedVirtualSpace::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
42void 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
75G1PageBasedVirtualSpace::~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
86size_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
95size_t G1PageBasedVirtualSpace::reserved_size() const {
96 return pointer_delta(_high_boundary, _low_boundary, sizeof(char));
97}
98
99size_t G1PageBasedVirtualSpace::uncommitted_size() const {
100 return reserved_size() - committed_size();
101}
102
103void 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
109size_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
110 return (addr - _low_boundary) / _page_size;
111}
112
113bool 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
118bool 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
123char* G1PageBasedVirtualSpace::page_start(size_t index) const {
124 return _low_boundary + index * _page_size;
125}
126
127bool G1PageBasedVirtualSpace::is_after_last_page(size_t index) const {
128 guarantee(index <= _committed.size(),
129 "Given boundary page " SIZE_FORMAT " is beyond managed page count " SIZE_FORMAT, index, _committed.size());
130 return index == _committed.size();
131}
132
133void G1PageBasedVirtualSpace::commit_preferred_pages(size_t start, size_t num_pages) {
134 vmassert(num_pages > 0, "No full pages to commit");
135 vmassert(start + num_pages <= _committed.size(),
136 "Tried to commit area from page " SIZE_FORMAT " to page " SIZE_FORMAT " "
137 "that is outside of managed space of " SIZE_FORMAT " pages",
138 start, start + num_pages, _committed.size());
139
140 char* start_addr = page_start(start);
141 size_t size = num_pages * _page_size;
142
143 os::commit_memory_or_exit(start_addr, size, _page_size, _executable,
144 err_msg("Failed to commit area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
145 p2i(start_addr), p2i(start_addr + size), size));
146}
147
148void G1PageBasedVirtualSpace::commit_tail() {
149 vmassert(_tail_size > 0, "The size of the tail area must be > 0 when reaching here");
150
151 char* const aligned_end_address = align_down(_high_boundary, _page_size);
152 os::commit_memory_or_exit(aligned_end_address, _tail_size, os::vm_page_size(), _executable,
153 err_msg("Failed to commit tail area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
154 p2i(aligned_end_address), p2i(_high_boundary), _tail_size));
155}
156
157void G1PageBasedVirtualSpace::commit_internal(size_t start_page, size_t end_page) {
158 guarantee(start_page < end_page,
159 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
160 guarantee(end_page <= _committed.size(),
161 "Given end page " SIZE_FORMAT " is beyond end of managed page amount of " SIZE_FORMAT, end_page, _committed.size());
162
163 size_t pages = end_page - start_page;
164 bool need_to_commit_tail = is_after_last_page(end_page) && is_last_page_partial();
165
166 // If we have to commit some (partial) tail area, decrease the amount of pages to avoid
167 // committing that in the full-page commit code.
168 if (need_to_commit_tail) {
169 pages--;
170 }
171
172 if (pages > 0) {
173 commit_preferred_pages(start_page, pages);
174 }
175
176 if (need_to_commit_tail) {
177 commit_tail();
178 }
179}
180
181char* G1PageBasedVirtualSpace::bounded_end_addr(size_t end_page) const {
182 return MIN2(_high_boundary, page_start(end_page));
183}
184
185void G1PageBasedVirtualSpace::pretouch_internal(size_t start_page, size_t end_page) {
186 guarantee(start_page < end_page,
187 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
188
189 os::pretouch_memory(page_start(start_page), bounded_end_addr(end_page), _page_size);
190}
191
192bool G1PageBasedVirtualSpace::commit(size_t start_page, size_t size_in_pages) {
193 // We need to make sure to commit all pages covered by the given area.
194 guarantee(is_area_uncommitted(start_page, size_in_pages), "Specified area is not uncommitted");
195
196 bool zero_filled = true;
197 size_t end_page = start_page + size_in_pages;
198
199 if (_special) {
200 // Check for dirty pages and update zero_filled if any found.
201 if (_dirty.get_next_one_offset(start_page, end_page) < end_page) {
202 zero_filled = false;
203 _dirty.clear_range(start_page, end_page);
204 }
205 } else {
206 commit_internal(start_page, end_page);
207 }
208 _committed.set_range(start_page, end_page);
209
210 return zero_filled;
211}
212
213void G1PageBasedVirtualSpace::uncommit_internal(size_t start_page, size_t end_page) {
214 guarantee(start_page < end_page,
215 "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
216
217 char* start_addr = page_start(start_page);
218 os::uncommit_memory(start_addr, pointer_delta(bounded_end_addr(end_page), start_addr, sizeof(char)));
219}
220
221void G1PageBasedVirtualSpace::uncommit(size_t start_page, size_t size_in_pages) {
222 guarantee(is_area_committed(start_page, size_in_pages), "checking");
223
224 size_t end_page = start_page + size_in_pages;
225 if (_special) {
226 // Mark that memory is dirty. If committed again the memory might
227 // need to be cleared explicitly.
228 _dirty.set_range(start_page, end_page);
229 } else {
230 uncommit_internal(start_page, end_page);
231 }
232
233 _committed.clear_range(start_page, end_page);
234}
235
236class G1PretouchTask : public AbstractGangTask {
237private:
238 char* volatile _cur_addr;
239 char* const _start_addr;
240 char* const _end_addr;
241 size_t _page_size;
242public:
243 G1PretouchTask(char* start_address, char* end_address, size_t page_size) :
244 AbstractGangTask("G1 PreTouch"),
245 _cur_addr(start_address),
246 _start_addr(start_address),
247 _end_addr(end_address),
248 _page_size(0) {
249#ifdef LINUX
250 _page_size = UseTransparentHugePages ? (size_t)os::vm_page_size(): page_size;
251#else
252 _page_size = page_size;
253#endif
254 }
255
256 virtual void work(uint worker_id) {
257 size_t const actual_chunk_size = MAX2(chunk_size(), _page_size);
258 while (true) {
259 char* touch_addr = Atomic::add(actual_chunk_size, &_cur_addr) - actual_chunk_size;
260 if (touch_addr < _start_addr || touch_addr >= _end_addr) {
261 break;
262 }
263 char* end_addr = touch_addr + MIN2(actual_chunk_size, pointer_delta(_end_addr, touch_addr, sizeof(char)));
264 os::pretouch_memory(touch_addr, end_addr, _page_size);
265 }
266 }
267
268 static size_t chunk_size() { return PreTouchParallelChunkSize; }
269};
270
271void G1PageBasedVirtualSpace::pretouch(size_t start_page, size_t size_in_pages, WorkGang* pretouch_gang) {
272 G1PretouchTask cl(page_start(start_page), bounded_end_addr(start_page + size_in_pages), _page_size);
273
274 if (pretouch_gang != NULL) {
275 size_t num_chunks = MAX2((size_t)1, size_in_pages * _page_size / MAX2(G1PretouchTask::chunk_size(), _page_size));
276
277 uint num_workers = MIN2((uint)num_chunks, pretouch_gang->active_workers());
278 log_debug(gc, heap)("Running %s with %u workers for " SIZE_FORMAT " work units pre-touching " SIZE_FORMAT "B.",
279 cl.name(), num_workers, num_chunks, size_in_pages * _page_size);
280 pretouch_gang->run_task(&cl, num_workers);
281 } else {
282 log_debug(gc, heap)("Running %s pre-touching " SIZE_FORMAT "B.",
283 cl.name(), size_in_pages * _page_size);
284 cl.work(0);
285 }
286}
287
288bool G1PageBasedVirtualSpace::contains(const void* p) const {
289 return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
290}
291
292#ifndef PRODUCT
293void G1PageBasedVirtualSpace::print_on(outputStream* out) {
294 out->print ("Virtual space:");
295 if (_special) out->print(" (pinned in memory)");
296 out->cr();
297 out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
298 out->print_cr(" - reserved: " SIZE_FORMAT, reserved_size());
299 out->print_cr(" - preferred page size: " SIZE_FORMAT, _page_size);
300 out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]", p2i(_low_boundary), p2i(_high_boundary));
301}
302
303void G1PageBasedVirtualSpace::print() {
304 print_on(tty);
305}
306#endif
307