1 /*
  2  * Copyright (c) 2001, 2019, 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/g1BiasedArray.hpp"
 27 #include "gc/g1/g1RegionToSpaceMapper.hpp"
 28 #include "logging/log.hpp"
 29 #include "memory/allocation.inline.hpp"
 30 #include "memory/virtualspace.hpp"
 31 #include "runtime/java.hpp"
 32 #include "runtime/os.inline.hpp"
 33 #include "services/memTracker.hpp"
 34 #include "utilities/align.hpp"
 35 #include "utilities/bitMap.inline.hpp"
 36 #include "utilities/formatBuffer.hpp"
 37 
 38 G1RegionToSpaceMapper::G1RegionToSpaceMapper(ReservedSpace rs,
 39                                              size_t used_size,
 40                                              size_t page_size,
 41                                              size_t region_granularity,
 42                                              size_t commit_factor,
 43                                              MemoryType type) :
 44   _listener(NULL),
 45   _storage(rs, used_size, page_size),
 46   _region_granularity(region_granularity),
 47   _commit_map(rs.size() * commit_factor / region_granularity, mtGC) {
 48   guarantee(is_power_of_2(page_size), "must be");
 49   guarantee(is_power_of_2(region_granularity), "must be");
 50 
 51   MemTracker::record_virtual_memory_type((address)rs.base(), type);
 52 }
 53 
 54 // G1RegionToSpaceMapper implementation where the region granularity is larger than
 55 // or the same as the commit granularity.
 56 // Basically, the space corresponding to one region region spans several OS pages.
 57 class G1RegionsLargerThanCommitSizeMapper : public G1RegionToSpaceMapper {
 58  private:
 59   size_t _pages_per_region;
 60 
 61  public:
 62   G1RegionsLargerThanCommitSizeMapper(ReservedSpace rs,
 63                                       size_t actual_size,
 64                                       size_t page_size,
 65                                       size_t alloc_granularity,
 66                                       size_t commit_factor,
 67                                       MemoryType type) :
 68     G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),
 69     _pages_per_region(alloc_granularity / (page_size * commit_factor)) {
 70 
 71     guarantee(alloc_granularity >= page_size, "allocation granularity smaller than commit granularity");
 72   }
 73 
 74   virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {
 75     size_t const start_page = (size_t)start_idx * _pages_per_region;
 76     bool zero_filled = _storage.commit(start_page, num_regions * _pages_per_region);
 77     if (AlwaysPreTouch) {
 78       _storage.pretouch(start_page, num_regions * _pages_per_region, pretouch_gang);
 79     }
 80     _commit_map.set_range(start_idx, start_idx + num_regions);
 81     fire_on_commit(start_idx, num_regions, zero_filled);
 82   }
 83 
 84   virtual void uncommit_regions(uint start_idx, size_t num_regions) {
 85     _storage.uncommit((size_t)start_idx * _pages_per_region, num_regions * _pages_per_region);
 86     _commit_map.clear_range(start_idx, start_idx + num_regions);
 87   }
 88 };
 89 
 90 // G1RegionToSpaceMapper implementation where the region granularity is smaller
 91 // than the commit granularity.
 92 // Basically, the contents of one OS page span several regions.
 93 class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
 94  private:
 95   class CommitRefcountArray : public G1BiasedMappedArray<uint> {
 96    protected:
 97      virtual uint default_value() const { return 0; }
 98   };
 99 
100   size_t _regions_per_page;
101 
102   CommitRefcountArray _refcounts;
103 
104   uintptr_t region_idx_to_page_idx(uint region) const {
105     return region / _regions_per_page;
106   }
107 
108  public:
109   G1RegionsSmallerThanCommitSizeMapper(ReservedSpace rs,
110                                        size_t actual_size,
111                                        size_t page_size,
112                                        size_t alloc_granularity,
113                                        size_t commit_factor,
114                                        MemoryType type) :
115     G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),
116     _regions_per_page((page_size * commit_factor) / alloc_granularity), _refcounts() {
117 
118     guarantee((page_size * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity");
119     _refcounts.initialize((HeapWord*)rs.base(), (HeapWord*)(rs.base() + align_up(rs.size(), page_size)), page_size);
120   }
121 
122   virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {
123     size_t const NoPage = ~(size_t)0;
124 
125     size_t first_committed = NoPage;
126     size_t num_committed = 0;
127 
128     bool all_zero_filled = true;
129 
130     for (uint i = start_idx; i < start_idx + num_regions; i++) {
131       assert(!_commit_map.at(i), "Trying to commit storage at region %u that is already committed", i);
132       size_t idx = region_idx_to_page_idx(i);
133       uint old_refcount = _refcounts.get_by_index(idx);
134 
135       bool zero_filled = false;
136       if (old_refcount == 0) {
137         if (first_committed == NoPage) {
138           first_committed = idx;
139           num_committed = 1;
140         } else {
141           num_committed++;
142         }
143         zero_filled = _storage.commit(idx, 1);
144       }
145       all_zero_filled &= zero_filled;
146 
147       _refcounts.set_by_index(idx, old_refcount + 1);
148       _commit_map.set_bit(i);
149     }
150     if (AlwaysPreTouch && num_committed > 0) {
151       _storage.pretouch(first_committed, num_committed, pretouch_gang);
152     }
153     fire_on_commit(start_idx, num_regions, all_zero_filled);
154   }
155 
156   virtual void uncommit_regions(uint start_idx, size_t num_regions) {
157     for (uint i = start_idx; i < start_idx + num_regions; i++) {
158       assert(_commit_map.at(i), "Trying to uncommit storage at region %u that is not committed", i);
159       size_t idx = region_idx_to_page_idx(i);
160       uint old_refcount = _refcounts.get_by_index(idx);
161       assert(old_refcount > 0, "must be");
162       if (old_refcount == 1) {
163         _storage.uncommit(idx, 1);
164       }
165       _refcounts.set_by_index(idx, old_refcount - 1);
166       _commit_map.clear_bit(i);
167     }
168   }
169 };
170 
171 void G1RegionToSpaceMapper::fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
172   if (_listener != NULL) {
173     _listener->on_commit(start_idx, num_regions, zero_filled);
174   }
175 }
176 
177 static bool map_nvdimm_space(ReservedSpace rs) {
178   assert(AllocateOldGenAt != NULL, "");
179   int _backing_fd = os::create_file_for_heap(AllocateOldGenAt);
180   if (_backing_fd == -1) {
181     log_error(gc, init)("Could not create file for Old generation at location %s", AllocateOldGenAt);
182     return false;
183   }
184   // commit this memory in nv-dimm
185   char* ret = os::attempt_reserve_memory_at(rs.size(), rs.base(), _backing_fd);
186 
187   if (ret != rs.base()) {
188     if (ret != NULL) {
189       os::unmap_memory(rs.base(), rs.size());
190     }
191     log_error(gc, init)("Error in mapping Old Gen to given AllocateOldGenAt = %s", AllocateOldGenAt);
192     os::close(_backing_fd);
193     return false;
194   }
195 
196   os::close(_backing_fd);
197   return true;
198 }
199 
200 G1RegionToHeteroSpaceMapper::G1RegionToHeteroSpaceMapper(ReservedSpace rs,
201                                                          size_t actual_size,
202                                                          size_t page_size,
203                                                          size_t alloc_granularity,
204                                                          size_t commit_factor,
205                                                          MemoryType type) :
206   G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),
207   _rs(rs),
208   _dram_mapper(NULL),
209   _num_committed_dram(0),
210   _num_committed_nvdimm(0),
211   _start_index_of_dram(0),
212   _page_size(page_size),
213   _commit_factor(commit_factor),
214   _type(type) {
215   assert(actual_size == 2 * MaxHeapSize, "For 2-way heterogenuous heap, reserved space is two times MaxHeapSize");
216 }
217 
218 bool G1RegionToHeteroSpaceMapper::initialize() {
219   // Since we need to re-map the reserved space - 'Xmx' to nv-dimm and 'Xmx' to dram, we need to release the reserved memory first.
220   // Because on some OSes (e.g. Windows) you cannot do a file mapping on memory reserved with regular mapping.
221   os::release_memory(_rs.base(), _rs.size());
222   // First half of size Xmx is for nv-dimm.
223   ReservedSpace rs_nvdimm = _rs.first_part(MaxHeapSize);
224   assert(rs_nvdimm.base() == _rs.base(), "We should get the same base address");
225 
226   // Second half of reserved memory is mapped to dram.
227   ReservedSpace rs_dram = _rs.last_part(MaxHeapSize);
228 
229   assert(rs_dram.size() == rs_nvdimm.size() && rs_nvdimm.size() == MaxHeapSize, "They all should be same");
230 
231   // Reserve dram memory
232   char* base = os::attempt_reserve_memory_at(rs_dram.size(), rs_dram.base());
233   if (base != rs_dram.base()) {
234     if (base != NULL) {
235       os::release_memory(base, rs_dram.size());
236     }
237     log_error(gc, init)("Error in re-mapping memory on dram during G1 heterogenous memory initialization");
238     return false;
239   }
240 
241   // We reserve and commit this entire space to NV-DIMM.
242   if (!map_nvdimm_space(rs_nvdimm)) {
243     log_error(gc, init)("Error in re-mapping memory to nv-dimm during G1 heterogenous memory initialization");
244     return false;
245   }
246 
247   if (_region_granularity >= (_page_size * _commit_factor)) {
248     _dram_mapper = new G1RegionsLargerThanCommitSizeMapper(rs_dram, rs_dram.size(), _page_size, _region_granularity, _commit_factor, _type);
249   } else {
250     _dram_mapper = new G1RegionsSmallerThanCommitSizeMapper(rs_dram, rs_dram.size(), _page_size, _region_granularity, _commit_factor, _type);
251   }
252 
253   _start_index_of_dram = (uint)(rs_nvdimm.size() / _region_granularity);
254   return true;
255 }
256 
257 void G1RegionToHeteroSpaceMapper::commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {
258   uint end_idx = (start_idx + (uint)num_regions - 1);
259 
260   uint num_dram = end_idx >= _start_index_of_dram ? MIN2((end_idx - _start_index_of_dram + 1), (uint)num_regions) : 0;
261   uint num_nvdimm = (uint)num_regions - num_dram;
262 
263   if (num_nvdimm > 0) {
264     // We do not need to commit nv-dimm regions, since they are committed in the beginning.
265     _num_committed_nvdimm += num_nvdimm;
266   }
267   if (num_dram > 0) {
268     _dram_mapper->commit_regions(start_idx > _start_index_of_dram ? (start_idx - _start_index_of_dram) : 0, num_dram, pretouch_gang);
269     _num_committed_dram += num_dram;
270   }
271 }
272 
273 void G1RegionToHeteroSpaceMapper::uncommit_regions(uint start_idx, size_t num_regions) {
274   uint end_idx = (start_idx + (uint)num_regions - 1);
275   uint num_dram = end_idx >= _start_index_of_dram ? MIN2((end_idx - _start_index_of_dram + 1), (uint)num_regions) : 0;
276   uint num_nvdimm = (uint)num_regions - num_dram;
277 
278   if (num_nvdimm > 0) {
279     // We do not uncommit memory for nv-dimm regions.
280     _num_committed_nvdimm -= num_nvdimm;
281   }
282 
283   if (num_dram > 0) {
284     _dram_mapper->uncommit_regions(start_idx > _start_index_of_dram ? (start_idx - _start_index_of_dram) : 0, num_dram);
285     _num_committed_dram -= num_dram;
286   }
287 }
288 
289 uint G1RegionToHeteroSpaceMapper::num_committed_dram() const {
290   return _num_committed_dram;
291 }
292 
293 uint G1RegionToHeteroSpaceMapper::num_committed_nvdimm() const {
294   return _num_committed_nvdimm;
295 }
296 
297 G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_heap_mapper(ReservedSpace rs,
298                                                                  size_t actual_size,
299                                                                  size_t page_size,
300                                                                  size_t region_granularity,
301                                                                  size_t commit_factor,
302                                                                  MemoryType type) {
303   if (AllocateOldGenAt != NULL) {
304     G1RegionToHeteroSpaceMapper* mapper = new G1RegionToHeteroSpaceMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);
305     if (!mapper->initialize()) {
306       delete mapper;
307       return NULL;
308     }
309     return (G1RegionToSpaceMapper*)mapper;
310   } else {
311     return create_mapper(rs, actual_size, page_size, region_granularity, commit_factor, type);
312   }
313 }
314 
315 G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_mapper(ReservedSpace rs,
316                                                             size_t actual_size,
317                                                             size_t page_size,
318                                                             size_t region_granularity,
319                                                             size_t commit_factor,
320                                                             MemoryType type) {
321   if (region_granularity >= (page_size * commit_factor)) {
322     return new G1RegionsLargerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);
323   } else {
324     return new G1RegionsSmallerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);
325   }
326 }
327 
328 void G1RegionToSpaceMapper::commit_and_set_special() {
329   _storage.commit_and_set_special();
330 }