1 /*
   2  * Copyright (c) 2005, 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/parallel/parMarkBitMap.inline.hpp"
  27 #include "gc/parallel/psCompactionManager.inline.hpp"
  28 #include "gc/parallel/psParallelCompact.inline.hpp"
  29 #include "oops/oop.inline.hpp"
  30 #include "runtime/atomic.hpp"
  31 #include "runtime/os.hpp"
  32 #include "services/memTracker.hpp"
  33 #include "utilities/align.hpp"
  34 #include "utilities/bitMap.inline.hpp"
  35 
  36 bool
  37 ParMarkBitMap::initialize(MemRegion covered_region)
  38 {
  39   const idx_t bits = bits_required(covered_region);
  40   // The bits will be divided evenly between two bitmaps; each of them should be
  41   // an integral number of words.
  42   assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");
  43 
  44   const size_t words = bits / BitsPerWord;
  45   const size_t raw_bytes = words * sizeof(idx_t);
  46   const size_t page_sz = os::page_size_for_region_aligned(raw_bytes, 10);
  47   const size_t granularity = os::vm_allocation_granularity();
  48   _reserved_byte_size = align_up(raw_bytes, MAX2(page_sz, granularity));
  49 
  50   const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
  51     MAX2(page_sz, granularity);
  52   ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0);
  53   os::trace_page_sizes("Mark Bitmap", raw_bytes, raw_bytes, page_sz,
  54                        rs.base(), rs.size());
  55 
  56   MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
  57 
  58   _virtual_space = new PSVirtualSpace(rs, page_sz);
  59   if (_virtual_space != NULL && _virtual_space->expand_by(_reserved_byte_size)) {
  60     _region_start = covered_region.start();
  61     _region_size = covered_region.word_size();
  62     BitMap::bm_word_t* map = (BitMap::bm_word_t*)_virtual_space->reserved_low_addr();
  63     _beg_bits = BitMapView(map,             bits / 2);
  64     _end_bits = BitMapView(map + words / 2, bits / 2);
  65     return true;
  66   }
  67 
  68   _region_start = 0;
  69   _region_size = 0;
  70   if (_virtual_space != NULL) {
  71     delete _virtual_space;
  72     _virtual_space = NULL;
  73     // Release memory reserved in the space.
  74     rs.release();
  75   }
  76   return false;
  77 }
  78 
  79 #ifdef ASSERT
  80 extern size_t mark_bitmap_count;
  81 extern size_t mark_bitmap_size;
  82 #endif  // #ifdef ASSERT
  83 
  84 bool
  85 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
  86 {
  87   const idx_t beg_bit = addr_to_bit(addr);
  88   if (_beg_bits.par_set_bit(beg_bit)) {
  89     const idx_t end_bit = addr_to_bit(addr + size - 1);
  90     bool end_bit_ok = _end_bits.par_set_bit(end_bit);
  91     assert(end_bit_ok, "concurrency problem");
  92     DEBUG_ONLY(Atomic::inc(&mark_bitmap_count));
  93     DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
  94     return true;
  95   }
  96   return false;
  97 }
  98 
  99 inline bool
 100 ParMarkBitMap::is_live_words_in_range_in_cache(ParCompactionManager* cm, HeapWord* beg_addr) const {
 101   return cm->last_query_begin() == beg_addr;
 102 }
 103 
 104 inline void
 105 ParMarkBitMap::update_live_words_in_range_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj, size_t result) const {
 106   cm->set_last_query_begin(beg_addr);
 107   cm->set_last_query_object(end_obj);
 108   cm->set_last_query_return(result);
 109 }
 110 
 111 size_t
 112 ParMarkBitMap::live_words_in_range_helper(HeapWord* beg_addr, oop end_obj) const
 113 {
 114   assert(beg_addr <= (HeapWord*)end_obj, "bad range");
 115   assert(is_marked(end_obj), "end_obj must be live");
 116 
 117   idx_t live_bits = 0;
 118 
 119   // The bitmap routines require the right boundary to be word-aligned.
 120   const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
 121   const idx_t range_end = BitMap::word_align_up(end_bit);
 122 
 123   idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
 124   while (beg_bit < end_bit) {
 125     idx_t tmp_end = find_obj_end(beg_bit, range_end);
 126     assert(tmp_end < end_bit, "missing end bit");
 127     live_bits += tmp_end - beg_bit + 1;
 128     beg_bit = find_obj_beg(tmp_end + 1, range_end);
 129   }
 130   return bits_to_words(live_bits);
 131 }
 132 
 133 size_t
 134 ParMarkBitMap::live_words_in_range_use_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const
 135 {
 136   HeapWord* last_beg = cm->last_query_begin();
 137   oop last_obj = cm->last_query_object();
 138   size_t last_ret = cm->last_query_return();
 139   if (end_obj > last_obj) {
 140     last_ret = last_ret + live_words_in_range_helper((HeapWord*)last_obj, end_obj);
 141     last_obj = end_obj;
 142   } else if (end_obj < last_obj) {
 143     // The cached value is for an object that is to the left (lower address) of the current
 144     // end_obj. Calculate back from that cached value.
 145     if (pointer_delta((HeapWord*)end_obj, (HeapWord*)beg_addr) > pointer_delta((HeapWord*)last_obj, (HeapWord*)end_obj)) {
 146       last_ret = last_ret - live_words_in_range_helper((HeapWord*)end_obj, last_obj);
 147     } else {
 148       last_ret = live_words_in_range_helper(beg_addr, end_obj);
 149     }
 150     last_obj = end_obj;
 151   }
 152 
 153   update_live_words_in_range_cache(cm, last_beg, last_obj, last_ret);
 154   return last_ret;
 155 }
 156 
 157 size_t
 158 ParMarkBitMap::live_words_in_range(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const
 159 {
 160   // Try to reuse result from ParCompactionManager cache first.
 161   if (is_live_words_in_range_in_cache(cm, beg_addr)) {
 162     return live_words_in_range_use_cache(cm, beg_addr, end_obj);
 163   }
 164   size_t ret = live_words_in_range_helper(beg_addr, end_obj);
 165   update_live_words_in_range_cache(cm, beg_addr, end_obj, ret);
 166   return ret;
 167 }
 168 
 169 ParMarkBitMap::IterationStatus
 170 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
 171                        idx_t range_beg, idx_t range_end) const
 172 {
 173   DEBUG_ONLY(verify_bit(range_beg);)
 174   DEBUG_ONLY(verify_bit(range_end);)
 175   assert(range_beg <= range_end, "live range invalid");
 176 
 177   // The bitmap routines require the right boundary to be word-aligned.
 178   const idx_t search_end = BitMap::word_align_up(range_end);
 179 
 180   idx_t cur_beg = find_obj_beg(range_beg, search_end);
 181   while (cur_beg < range_end) {
 182     const idx_t cur_end = find_obj_end(cur_beg, search_end);
 183     if (cur_end >= range_end) {
 184       // The obj ends outside the range.
 185       live_closure->set_source(bit_to_addr(cur_beg));
 186       return incomplete;
 187     }
 188 
 189     const size_t size = obj_size(cur_beg, cur_end);
 190     IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
 191     if (status != incomplete) {
 192       assert(status == would_overflow || status == full, "sanity");
 193       return status;
 194     }
 195 
 196     // Successfully processed the object; look for the next object.
 197     cur_beg = find_obj_beg(cur_end + 1, search_end);
 198   }
 199 
 200   live_closure->set_source(bit_to_addr(range_end));
 201   return complete;
 202 }
 203 
 204 ParMarkBitMap::IterationStatus
 205 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
 206                        ParMarkBitMapClosure* dead_closure,
 207                        idx_t range_beg, idx_t range_end,
 208                        idx_t dead_range_end) const
 209 {
 210   DEBUG_ONLY(verify_bit(range_beg);)
 211   DEBUG_ONLY(verify_bit(range_end);)
 212   DEBUG_ONLY(verify_bit(dead_range_end);)
 213   assert(range_beg <= range_end, "live range invalid");
 214   assert(range_end <= dead_range_end, "dead range invalid");
 215 
 216   // The bitmap routines require the right boundary to be word-aligned.
 217   const idx_t live_search_end = BitMap::word_align_up(range_end);
 218   const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
 219 
 220   idx_t cur_beg = range_beg;
 221   if (range_beg < range_end && is_unmarked(range_beg)) {
 222     // The range starts with dead space.  Look for the next object, then fill.
 223     cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
 224     const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
 225     const size_t size = obj_size(range_beg, dead_space_end);
 226     dead_closure->do_addr(bit_to_addr(range_beg), size);
 227   }
 228 
 229   while (cur_beg < range_end) {
 230     const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
 231     if (cur_end >= range_end) {
 232       // The obj ends outside the range.
 233       live_closure->set_source(bit_to_addr(cur_beg));
 234       return incomplete;
 235     }
 236 
 237     const size_t size = obj_size(cur_beg, cur_end);
 238     IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
 239     if (status != incomplete) {
 240       assert(status == would_overflow || status == full, "sanity");
 241       return status;
 242     }
 243 
 244     // Look for the start of the next object.
 245     const idx_t dead_space_beg = cur_end + 1;
 246     cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
 247     if (cur_beg > dead_space_beg) {
 248       // Found dead space; compute the size and invoke the dead closure.
 249       const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
 250       const size_t size = obj_size(dead_space_beg, dead_space_end);
 251       dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
 252     }
 253   }
 254 
 255   live_closure->set_source(bit_to_addr(range_end));
 256   return complete;
 257 }
 258 
 259 #ifdef ASSERT
 260 void ParMarkBitMap::verify_clear() const
 261 {
 262   const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
 263   const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
 264   for (const idx_t* p = beg; p < end; ++p) {
 265     assert(*p == 0, "bitmap not clear");
 266   }
 267 }
 268 #endif  // #ifdef ASSERT