1 /*
   2  * Copyright (c) 2014, 2017, 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/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), _committed(mtGC), _page_size(0), _special(false),
  38   _dirty(mtGC), _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 size_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
 104   return (addr - _low_boundary) / _page_size;
 105 }
 106 
 107 bool G1PageBasedVirtualSpace::is_area_committed(size_t start_page, size_t size_in_pages) const {
 108   size_t end_page = start_page + size_in_pages;
 109   return _committed.get_next_zero_offset(start_page, end_page) >= end_page;
 110 }
 111 
 112 bool G1PageBasedVirtualSpace::is_area_uncommitted(size_t start_page, size_t size_in_pages) const {
 113   size_t end_page = start_page + size_in_pages;
 114   return _committed.get_next_one_offset(start_page, end_page) >= end_page;
 115 }
 116 
 117 char* G1PageBasedVirtualSpace::page_start(size_t index) const {
 118   return _low_boundary + index * _page_size;
 119 }
 120 
 121 bool G1PageBasedVirtualSpace::is_after_last_page(size_t index) const {
 122   guarantee(index <= _committed.size(),
 123             "Given boundary page " SIZE_FORMAT " is beyond managed page count " SIZE_FORMAT, index, _committed.size());
 124   return index == _committed.size();
 125 }
 126 
 127 void G1PageBasedVirtualSpace::commit_preferred_pages(size_t start, size_t num_pages) {
 128   vmassert(num_pages > 0, "No full pages to commit");
 129   vmassert(start + num_pages <= _committed.size(),
 130            "Tried to commit area from page " SIZE_FORMAT " to page " SIZE_FORMAT " "
 131            "that is outside of managed space of " SIZE_FORMAT " pages",
 132            start, start + num_pages, _committed.size());
 133 
 134   char* start_addr = page_start(start);
 135   size_t size = num_pages * _page_size;
 136 
 137   os::commit_memory_or_exit(start_addr, size, _page_size, _executable,
 138                             err_msg("Failed to commit area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
 139                             p2i(start_addr), p2i(start_addr + size), size));
 140 }
 141 
 142 void G1PageBasedVirtualSpace::commit_tail() {
 143   vmassert(_tail_size > 0, "The size of the tail area must be > 0 when reaching here");
 144 
 145   char* const aligned_end_address = align_down(_high_boundary, _page_size);
 146   os::commit_memory_or_exit(aligned_end_address, _tail_size, os::vm_page_size(), _executable,
 147                             err_msg("Failed to commit tail area from " PTR_FORMAT " to " PTR_FORMAT " of length " SIZE_FORMAT ".",
 148                             p2i(aligned_end_address), p2i(_high_boundary), _tail_size));
 149 }
 150 
 151 void G1PageBasedVirtualSpace::commit_internal(size_t start_page, size_t end_page) {
 152   guarantee(start_page < end_page,
 153             "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
 154   guarantee(end_page <= _committed.size(),
 155             "Given end page " SIZE_FORMAT " is beyond end of managed page amount of " SIZE_FORMAT, end_page, _committed.size());
 156 
 157   size_t pages = end_page - start_page;
 158   bool need_to_commit_tail = is_after_last_page(end_page) && is_last_page_partial();
 159 
 160   // If we have to commit some (partial) tail area, decrease the amount of pages to avoid
 161   // committing that in the full-page commit code.
 162   if (need_to_commit_tail) {
 163     pages--;
 164   }
 165 
 166   if (pages > 0) {
 167     commit_preferred_pages(start_page, pages);
 168   }
 169 
 170   if (need_to_commit_tail) {
 171     commit_tail();
 172   }
 173 }
 174 
 175 char* G1PageBasedVirtualSpace::bounded_end_addr(size_t end_page) const {
 176   return MIN2(_high_boundary, page_start(end_page));
 177 }
 178 
 179 void G1PageBasedVirtualSpace::pretouch_internal(size_t start_page, size_t end_page) {
 180   guarantee(start_page < end_page,
 181             "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
 182 
 183   os::pretouch_memory(page_start(start_page), bounded_end_addr(end_page), _page_size);
 184 }
 185 
 186 bool G1PageBasedVirtualSpace::commit(size_t start_page, size_t size_in_pages) {
 187   // We need to make sure to commit all pages covered by the given area.
 188   guarantee(is_area_uncommitted(start_page, size_in_pages), "Specified area is not uncommitted");
 189 
 190   bool zero_filled = true;
 191   size_t end_page = start_page + size_in_pages;
 192 
 193   if (_special) {
 194     // Check for dirty pages and update zero_filled if any found.
 195     if (_dirty.get_next_one_offset(start_page, end_page) < end_page) {
 196       zero_filled = false;
 197       _dirty.clear_range(start_page, end_page);
 198     }
 199   } else {
 200     commit_internal(start_page, end_page);
 201   }
 202   _committed.set_range(start_page, end_page);
 203 
 204   return zero_filled;
 205 }
 206 
 207 void G1PageBasedVirtualSpace::uncommit_internal(size_t start_page, size_t end_page) {
 208   guarantee(start_page < end_page,
 209             "Given start page " SIZE_FORMAT " is larger or equal to end page " SIZE_FORMAT, start_page, end_page);
 210 
 211   char* start_addr = page_start(start_page);
 212   os::uncommit_memory(start_addr, pointer_delta(bounded_end_addr(end_page), start_addr, sizeof(char)));
 213 }
 214 
 215 void G1PageBasedVirtualSpace::uncommit(size_t start_page, size_t size_in_pages) {
 216   guarantee(is_area_committed(start_page, size_in_pages), "checking");
 217 
 218   size_t end_page = start_page + size_in_pages;
 219   if (_special) {
 220     // Mark that memory is dirty. If committed again the memory might
 221     // need to be cleared explicitly.
 222     _dirty.set_range(start_page, end_page);
 223   } else {
 224     uncommit_internal(start_page, end_page);
 225   }
 226 
 227   _committed.clear_range(start_page, end_page);
 228 }
 229 
 230 class G1PretouchTask : public AbstractGangTask {
 231 private:
 232   char* volatile _cur_addr;
 233   char* const _start_addr;
 234   char* const _end_addr;
 235   size_t const _page_size;
 236 public:
 237   G1PretouchTask(char* start_address, char* end_address, size_t page_size) :
 238     AbstractGangTask("G1 PreTouch",
 239                      Universe::is_fully_initialized() &&
 240                      Thread::current()->is_Named_thread() ? GCId::current_raw() :
 241                                                             // During VM initialization there is
 242                                                             // no GC cycle that this task can be
 243                                                             // associated with.
 244                                                             GCId::undefined()),
 245     _cur_addr(start_address),
 246     _start_addr(start_address),
 247     _end_addr(end_address),
 248     _page_size(page_size) {
 249   }
 250 
 251   virtual void work(uint worker_id) {
 252     size_t const actual_chunk_size = MAX2(chunk_size(), _page_size);
 253     while (true) {
 254       char* touch_addr = Atomic::add(actual_chunk_size, &_cur_addr) - actual_chunk_size;
 255       if (touch_addr < _start_addr || touch_addr >= _end_addr) {
 256         break;
 257       }
 258       char* end_addr = touch_addr + MIN2(actual_chunk_size, pointer_delta(_end_addr, touch_addr, sizeof(char)));
 259       os::pretouch_memory(touch_addr, end_addr, _page_size);
 260     }
 261   }
 262 
 263   static size_t chunk_size() { return PreTouchParallelChunkSize; }
 264 };
 265 
 266 void G1PageBasedVirtualSpace::pretouch(size_t start_page, size_t size_in_pages, WorkGang* pretouch_gang) {
 267   G1PretouchTask cl(page_start(start_page), bounded_end_addr(start_page + size_in_pages), _page_size);
 268 
 269   if (pretouch_gang != NULL) {
 270     size_t num_chunks = MAX2((size_t)1, size_in_pages * _page_size / MAX2(G1PretouchTask::chunk_size(), _page_size));
 271 
 272     uint num_workers = MIN2((uint)num_chunks, pretouch_gang->active_workers());
 273     log_debug(gc, heap)("Running %s with %u workers for " SIZE_FORMAT " work units pre-touching " SIZE_FORMAT "B.",
 274                         cl.name(), num_workers, num_chunks, size_in_pages * _page_size);
 275     pretouch_gang->run_task(&cl, num_workers);
 276   } else {
 277     log_debug(gc, heap)("Running %s pre-touching " SIZE_FORMAT "B.",
 278                         cl.name(), size_in_pages * _page_size);
 279     cl.work(0);
 280   }
 281 }
 282 
 283 bool G1PageBasedVirtualSpace::contains(const void* p) const {
 284   return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
 285 }
 286 
 287 #ifndef PRODUCT
 288 void G1PageBasedVirtualSpace::print_on(outputStream* out) {
 289   out->print   ("Virtual space:");
 290   if (_special) out->print(" (pinned in memory)");
 291   out->cr();
 292   out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
 293   out->print_cr(" - reserved:  " SIZE_FORMAT, reserved_size());
 294   out->print_cr(" - preferred page size: " SIZE_FORMAT, _page_size);
 295   out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT ", " PTR_FORMAT "]",  p2i(_low_boundary), p2i(_high_boundary));
 296 }
 297 
 298 void G1PageBasedVirtualSpace::print() {
 299   print_on(tty);
 300 }
 301 #endif
--- EOF ---