1 /*

     2  * Copyright 2005-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 # include "incls/_precompiled.incl"

    26 # include "incls/_parMarkBitMap.cpp.incl"

    27 

    28 bool

    29 ParMarkBitMap::initialize(MemRegion covered_region)

    30 {

    31   const idx_t bits = bits_required(covered_region);

    32   // The bits will be divided evenly between two bitmaps; each of them should be

    33   // an integral number of words.

    34   assert(bits % (BitsPerWord * 2) == 0, "region size unaligned");

    35 

    36   const size_t words = bits / BitsPerWord;

    37   const size_t raw_bytes = words * sizeof(idx_t);

    38   const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);

    39   const size_t granularity = os::vm_allocation_granularity();

    40   const size_t bytes = align_size_up(raw_bytes, MAX2(page_sz, granularity));

    41 

    42   const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :

    43     MAX2(page_sz, granularity);

    44   ReservedSpace rs(bytes, rs_align, false);

    45   os::trace_page_sizes("par bitmap", raw_bytes, raw_bytes, page_sz,

    46                        rs.base(), rs.size());

    47   _virtual_space = new PSVirtualSpace(rs, page_sz);

    48   if (_virtual_space != NULL && _virtual_space->expand_by(bytes)) {

    49     _region_start = covered_region.start();

    50     _region_size = covered_region.word_size();

    51     idx_t* map = (idx_t*)_virtual_space->reserved_low_addr();

    52     _beg_bits.set_map(map);

    53     _beg_bits.set_size(bits / 2);

    54     _end_bits.set_map(map + words / 2);

    55     _end_bits.set_size(bits / 2);

    56     return true;

    57   }

    58 

    59   _region_start = 0;

    60   _region_size = 0;

    61   if (_virtual_space != NULL) {

    62     delete _virtual_space;

    63     _virtual_space = NULL;

    64   }

    65   return false;

    66 }

    67 

    68 #ifdef ASSERT

    69 extern size_t mark_bitmap_count;

    70 extern size_t mark_bitmap_size;

    71 #endif  // #ifdef ASSERT

    72 

    73 bool

    74 ParMarkBitMap::mark_obj(HeapWord* addr, size_t size)

    75 {

    76   const idx_t beg_bit = addr_to_bit(addr);

    77   if (_beg_bits.par_set_bit(beg_bit)) {

    78     const idx_t end_bit = addr_to_bit(addr + size - 1);

    79     bool end_bit_ok = _end_bits.par_set_bit(end_bit);

    80     assert(end_bit_ok, "concurrency problem");

    81     DEBUG_ONLY(Atomic::inc_ptr(&mark_bitmap_count));

    82     DEBUG_ONLY(Atomic::add_ptr(size, &mark_bitmap_size));

    83     return true;

    84   }

    85   return false;

    86 }

    87 

    88 size_t

    89 ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, HeapWord* end_addr) const

    90 {

    91   assert(beg_addr <= end_addr, "bad range");

    92 

    93   idx_t live_bits = 0;

    94 

    95   // The bitmap routines require the right boundary to be word-aligned.

    96   const idx_t end_bit = addr_to_bit(end_addr);

    97   const idx_t range_end = BitMap::word_align_up(end_bit);

    98 

    99   idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);

   100   while (beg_bit < end_bit) {

   101     idx_t tmp_end = find_obj_end(beg_bit, range_end);

   102     if (tmp_end < end_bit) {

   103       live_bits += tmp_end - beg_bit + 1;

   104       beg_bit = find_obj_beg(tmp_end + 1, range_end);

   105     } else {

   106       live_bits += end_bit - beg_bit;  // No + 1 here; end_bit is not counted.

   107       return bits_to_words(live_bits);

   108     }

   109   }

   110   return bits_to_words(live_bits);

   111 }

   112 

   113 size_t ParMarkBitMap::live_words_in_range(HeapWord* beg_addr, oop end_obj) const

   114 {

   115   assert(beg_addr <= (HeapWord*)end_obj, "bad range");

   116   assert(is_marked(end_obj), "end_obj must be live");

   117 

   118   idx_t live_bits = 0;

   119 

   120   // The bitmap routines require the right boundary to be word-aligned.

   121   const idx_t end_bit = addr_to_bit((HeapWord*)end_obj);

   122   const idx_t range_end = BitMap::word_align_up(end_bit);

   123 

   124   idx_t beg_bit = find_obj_beg(addr_to_bit(beg_addr), range_end);

   125   while (beg_bit < end_bit) {

   126     idx_t tmp_end = find_obj_end(beg_bit, range_end);

   127     assert(tmp_end < end_bit, "missing end bit");

   128     live_bits += tmp_end - beg_bit + 1;

   129     beg_bit = find_obj_beg(tmp_end + 1, range_end);

   130   }

   131   return bits_to_words(live_bits);

   132 }

   133 

   134 ParMarkBitMap::IterationStatus

   135 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,

   136                        idx_t range_beg, idx_t range_end) const

   137 {

   138   DEBUG_ONLY(verify_bit(range_beg);)

   139   DEBUG_ONLY(verify_bit(range_end);)

   140   assert(range_beg <= range_end, "live range invalid");

   141 

   142   // The bitmap routines require the right boundary to be word-aligned.

   143   const idx_t search_end = BitMap::word_align_up(range_end);

   144 

   145   idx_t cur_beg = find_obj_beg(range_beg, search_end);

   146   while (cur_beg < range_end) {

   147     const idx_t cur_end = find_obj_end(cur_beg, search_end);

   148     if (cur_end >= range_end) {

   149       // The obj ends outside the range.

   150       live_closure->set_source(bit_to_addr(cur_beg));

   151       return incomplete;

   152     }

   153 

   154     const size_t size = obj_size(cur_beg, cur_end);

   155     IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);

   156     if (status != incomplete) {

   157       assert(status == would_overflow || status == full, "sanity");

   158       return status;

   159     }

   160 

   161     // Successfully processed the object; look for the next object.

   162     cur_beg = find_obj_beg(cur_end + 1, search_end);

   163   }

   164 

   165   live_closure->set_source(bit_to_addr(range_end));

   166   return complete;

   167 }

   168 

   169 ParMarkBitMap::IterationStatus

   170 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,

   171                        ParMarkBitMapClosure* dead_closure,

   172                        idx_t range_beg, idx_t range_end,

   173                        idx_t dead_range_end) const

   174 {

   175   DEBUG_ONLY(verify_bit(range_beg);)

   176   DEBUG_ONLY(verify_bit(range_end);)

   177   DEBUG_ONLY(verify_bit(dead_range_end);)

   178   assert(range_beg <= range_end, "live range invalid");

   179   assert(range_end <= dead_range_end, "dead range invalid");

   180 

   181   // The bitmap routines require the right boundary to be word-aligned.

   182   const idx_t live_search_end = BitMap::word_align_up(range_end);

   183   const idx_t dead_search_end = BitMap::word_align_up(dead_range_end);

   184 

   185   idx_t cur_beg = range_beg;

   186   if (range_beg < range_end && is_unmarked(range_beg)) {

   187     // The range starts with dead space.  Look for the next object, then fill.

   188     cur_beg = find_obj_beg(range_beg + 1, dead_search_end);

   189     const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);

   190     const size_t size = obj_size(range_beg, dead_space_end);

   191     dead_closure->do_addr(bit_to_addr(range_beg), size);

   192   }

   193 

   194   while (cur_beg < range_end) {

   195     const idx_t cur_end = find_obj_end(cur_beg, live_search_end);

   196     if (cur_end >= range_end) {

   197       // The obj ends outside the range.

   198       live_closure->set_source(bit_to_addr(cur_beg));

   199       return incomplete;

   200     }

   201 

   202     const size_t size = obj_size(cur_beg, cur_end);

   203     IterationStatus status = live_closure->do_addr(bit_to_addr(cur_beg), size);

   204     if (status != incomplete) {

   205       assert(status == would_overflow || status == full, "sanity");

   206       return status;

   207     }

   208 

   209     // Look for the start of the next object.

   210     const idx_t dead_space_beg = cur_end + 1;

   211     cur_beg = find_obj_beg(dead_space_beg, dead_search_end);

   212     if (cur_beg > dead_space_beg) {

   213       // Found dead space; compute the size and invoke the dead closure.

   214       const idx_t dead_space_end = MIN2(cur_beg - 1, dead_range_end - 1);

   215       const size_t size = obj_size(dead_space_beg, dead_space_end);

   216       dead_closure->do_addr(bit_to_addr(dead_space_beg), size);

   217     }

   218   }

   219 

   220   live_closure->set_source(bit_to_addr(range_end));

   221   return complete;

   222 }

   223 

   224 #ifndef PRODUCT

   225 void ParMarkBitMap::reset_counters()

   226 {

   227   _cas_tries = _cas_retries = _cas_by_another = 0;

   228 }

   229 #endif  // #ifndef PRODUCT

   230 

   231 #ifdef ASSERT

   232 void ParMarkBitMap::verify_clear() const

   233 {

   234   const idx_t* const beg = (const idx_t*)_virtual_space->committed_low_addr();

   235   const idx_t* const end = (const idx_t*)_virtual_space->committed_high_addr();

   236   for (const idx_t* p = beg; p < end; ++p) {

   237     assert(*p == 0, "bitmap not clear");

   238   }

   239 }

   240 #endif  // #ifdef ASSERT