1 /*
   2  * Copyright (c) 2005, 2012, 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_implementation/parallelScavenge/parMarkBitMap.hpp"
  27 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
  28 #include "oops/oop.inline.hpp"
  29 #include "runtime/os.hpp"
  30 #include "utilities/bitMap.inline.hpp"
  31 #include "services/memTracker.hpp"
  32 #ifdef TARGET_OS_FAMILY_linux
  33 # include "os_linux.inline.hpp"
  34 #endif
  35 #ifdef TARGET_OS_FAMILY_solaris
  36 # include "os_solaris.inline.hpp"
  37 #endif
  38 #ifdef TARGET_OS_FAMILY_windows
  39 # include "os_windows.inline.hpp"
  40 #endif
  41 #ifdef TARGET_OS_FAMILY_bsd
  42 # include "os_bsd.inline.hpp"
  43 #endif
  44 
  45 bool
  46 ParMarkBitMap::initialize(MemRegion covered_region)
  47 {
  48   const idx_t bits = bits_required(covered_region);
  49   // The bits will be divided evenly between two bitmaps; each of them should be
  50   // an integral number of words.
  51   assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");
  52 
  53   const size_t words = bits / BitsPerWord;
  54   const size_t raw_bytes = words * sizeof(idx_t);
  55   const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);
  56   const size_t granularity = os::vm_allocation_granularity();
  57   _reserved_byte_size = align_size_up(raw_bytes, MAX2(page_sz, granularity));
  58 
  59   const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
  60     MAX2(page_sz, granularity);
  61   ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0);
  62   os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz,
  63                        rs.base(), rs.size());
  64 
  65   MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
  66 
  67   _virtual_space = new PSVirtualSpace(rs, page_sz);
  68   if (_virtual_space != NULL && _virtual_space->expand_by(_reserved_byte_size)) {
  69     _region_start = covered_region.start();
  70     _region_size = covered_region.word_size();
  71     idx_t* map = (idx_t*)_virtual_space->reserved_low_addr();
  72     _beg_bits.set_map(map);
  73     _beg_bits.set_size(bits / 2);
  74     _end_bits.set_map(map + words / 2);
  75     _end_bits.set_size(bits / 2);
  76     return true;
  77   }
  78 
  79   _region_start = 0;
  80   _region_size = 0;
  81   if (_virtual_space != NULL) {
  82     delete _virtual_space;
  83     _virtual_space = NULL;
  84     // Release memory reserved in the space.
  85     rs.release();
  86   }
  87   return false;
  88 }
  89 
  90 #ifdef ASSERT
  91 extern size_t mark_bitmap_count;
  92 extern size_t mark_bitmap_size;
  93 #endif  // #ifdef ASSERT
  94 
  95 bool
  96 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)
  97 {
  98   const idx_t beg_bit = addr_to_bit(addr);
  99   if (_beg_bits.par_set_bit(beg_bit)) {
 100     const idx_t end_bit = addr_to_bit(addr + size - 1);
 101     bool end_bit_ok = _end_bits.par_set_bit(end_bit);
 102     assert(end_bit_ok, "concurrency problem");
 103     DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));
 104     DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));
 105     return true;
 106   }
 107   return false;
 108 }
 109 
 110 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const
 111 {
 112   assert(beg_addr <= (HeapWord*)end_obj, "bad range");
 113   assert(is_marked(end_obj), "end_obj must be live");
 114 
 115   idx_t live_bits = 0;
 116 
 117   // The bitmap routines require the right boundary to be word-aligned.
 118   const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);
 119   const idx_t range_end = BitMap::word_align_up(end_bit);
 120 
 121   idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);
 122   while (beg_bit < end_bit) {
 123     idx_t tmp_end = find_obj_end(beg_bit, range_end);
 124     assert(tmp_end < end_bit, "missing end bit");
 125     live_bits += tmp_end - beg_bit + 1;
 126     beg_bit = find_obj_beg(tmp_end + 1, range_end);
 127   }
 128   return bits_to_words(live_bits);
 129 }
 130 
 131 ParMarkBitMap::IterationStatus
 132 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
 133                        idx_t range_beg, idx_t range_end) const
 134 {
 135   DEBUG_ONLY(verify_bit(range_beg);)
 136   DEBUG_ONLY(verify_bit(range_end);)
 137   assert(range_beg <= range_end, "live range invalid");
 138 
 139   // The bitmap routines require the right boundary to be word-aligned.
 140   const idx_t search_end = BitMap::word_align_up(range_end);
 141 
 142   idx_t cur_beg = find_obj_beg(range_beg, search_end);
 143   while (cur_beg < range_end) {
 144     const idx_t cur_end = find_obj_end(cur_beg, search_end);
 145     if (cur_end >= range_end) {
 146       // The obj ends outside the range.
 147       live_closure->set_source(bit_to_addr(cur_beg));
 148       return incomplete;
 149     }
 150 
 151     const size_t size = obj_size(cur_beg, cur_end);
 152     IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
 153     if (status != incomplete) {
 154       assert(status == would_overflow || status == full, "sanity");
 155       return status;
 156     }
 157 
 158     // Successfully processed the object; look for the next object.
 159     cur_beg = find_obj_beg(cur_end + 1, search_end);
 160   }
 161 
 162   live_closure->set_source(bit_to_addr(range_end));
 163   return complete;
 164 }
 165 
 166 ParMarkBitMap::IterationStatus
 167 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
 168                        ParMarkBitMapClosure* dead_closure,
 169                        idx_t range_beg, idx_t range_end,
 170                        idx_t dead_range_end) const
 171 {
 172   DEBUG_ONLY(verify_bit(range_beg);)
 173   DEBUG_ONLY(verify_bit(range_end);)
 174   DEBUG_ONLY(verify_bit(dead_range_end);)
 175   assert(range_beg <= range_end, "live range invalid");
 176   assert(range_end <= dead_range_end, "dead range invalid");
 177 
 178   // The bitmap routines require the right boundary to be word-aligned.
 179   const idx_t live_search_end = BitMap::word_align_up(range_end);
 180   const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);
 181 
 182   idx_t cur_beg = range_beg;
 183   if (range_beg < range_end && is_unmarked(range_beg)) {
 184     // The range starts with dead space.  Look for the next object, then fill.
 185     cur_beg = find_obj_beg(range_beg + 1, dead_search_end);
 186     const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
 187     const size_t size = obj_size(range_beg, dead_space_end);
 188     dead_closure->do_addr(bit_to_addr(range_beg), size);
 189   }
 190 
 191   while (cur_beg < range_end) {
 192     const idx_t cur_end = find_obj_end(cur_beg, live_search_end);
 193     if (cur_end >= range_end) {
 194       // The obj ends outside the range.
 195       live_closure->set_source(bit_to_addr(cur_beg));
 196       return incomplete;
 197     }
 198 
 199     const size_t size = obj_size(cur_beg, cur_end);
 200     IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);
 201     if (status != incomplete) {
 202       assert(status == would_overflow || status == full, "sanity");
 203       return status;
 204     }
 205 
 206     // Look for the start of the next object.
 207     const idx_t dead_space_beg = cur_end + 1;
 208     cur_beg = find_obj_beg(dead_space_beg, dead_search_end);
 209     if (cur_beg > dead_space_beg) {
 210       // Found dead space; compute the size and invoke the dead closure.
 211       const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);
 212       const size_t size = obj_size(dead_space_beg, dead_space_end);
 213       dead_closure->do_addr(bit_to_addr(dead_space_beg), size);
 214     }
 215   }
 216 
 217   live_closure->set_source(bit_to_addr(range_end));
 218   return complete;
 219 }
 220 
 221 #ifdef ASSERT
 222 void ParMarkBitMap::verify_clear() const
 223 {
 224   const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();
 225   const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();
 226   for (const idx_t* p = beg; p < end; ++p) {
 227     assert(*p == 0, "bitmap not clear");
 228   }
 229 }
 230 #endif  // #ifdef ASSERT