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 /*

  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "gc_implementation/parallelScavenge/parMarkBitMap.hpp"

 #include "gc_implementation/parallelScavenge/parMarkBitMap.inline.hpp"

 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"

 #include "oops/oop.inline.hpp"

 #include "runtime/os.hpp"

 #include "utilities/bitMap.inline.hpp"

 #ifdef TARGET_OS_FAMILY_linux

 # include "os_linux.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_solaris

 # include "os_solaris.inline.hpp"

 #endif

 #ifdef TARGET_OS_FAMILY_windows

 # include "os_windows.inline.hpp"

 #endif

 bool

 ParMarkBitMap::initialize(MemRegion covered_region)

 {

   const idx_t bits = bits_required(covered_region);

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

   // an integral number of words.

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

   const size_t words = bits / BitsPerWord;

   const size_t raw_bytes = words * sizeof(idx_t);

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

   const size_t granularity = os::vm_allocation_granularity();

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

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

     MAX2(page_sz, granularity);

   ReservedSpace rs(bytes, rs_align, rs_align > 0);

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

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

   _virtual_space = new PSVirtualSpace(rs, page_sz);

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

     _region_start = covered_region.start();

     _region_size = covered_region.word_size();

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

     _beg_bits.set_map(map);

     _beg_bits.set_size(bits / 2);

     _end_bits.set_map(map + words / 2);

     _end_bits.set_size(bits / 2);

     return true;

   }

   _region_start = 0;

   _region_size = 0;

   if (_virtual_space != NULL) {

     delete _virtual_space;

     _virtual_space = NULL;

     // Release memory reserved in the space.

     rs.release();

   }

   return false;

 }

 #ifdef ASSERT

 extern size_t mark_bitmap_count;

 extern size_t mark_bitmap_size;

 #endif  // #ifdef ASSERT

 bool

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

 {

   const idx_t beg_bit = addr_to_bit(addr);

   if (_beg_bits.par_set_bit(beg_bit)) {

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

     bool end_bit_ok = _end_bits.par_set_bit(end_bit);

     assert(end_bit_ok, "concurrency problem");

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

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

     return true;

   }

   return false;

 }

 size_t

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

 {

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

   idx_t live_bits = 0;

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

   const idx_t end_bit = addr_to_bit(end_addr);

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

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

   while (beg_bit < end_bit) {

     idx_t tmp_end = find_obj_end(beg_bit, range_end);

     if (tmp_end < end_bit) {

       live_bits += tmp_end - beg_bit + 1;

       beg_bit = find_obj_beg(tmp_end + 1, range_end);

     } else {

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

       return bits_to_words(live_bits);

     }

   }

   return bits_to_words(live_bits);

 }

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

 {

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

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

   idx_t live_bits = 0;

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

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

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

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

   while (beg_bit < end_bit) {

     idx_t tmp_end = find_obj_end(beg_bit, range_end);

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

     live_bits += tmp_end - beg_bit + 1;

     beg_bit = find_obj_beg(tmp_end + 1, range_end);

   }

   return bits_to_words(live_bits);

 }

 ParMarkBitMap::IterationStatus

 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,

                        idx_t range_beg, idx_t range_end) const

 {

   DEBUG_ONLY(verify_bit(range_beg);)

   DEBUG_ONLY(verify_bit(range_end);)

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

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

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

   idx_t cur_beg = find_obj_beg(range_beg, search_end);

   while (cur_beg < range_end) {

     const idx_t cur_end = find_obj_end(cur_beg, search_end);

     if (cur_end >= range_end) {

       // The obj ends outside the range.

       live_closure->set_source(bit_to_addr(cur_beg));

       return incomplete;

     }

     const size_t size = obj_size(cur_beg, cur_end);

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

     if (status != incomplete) {

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

       return status;

     }

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

     cur_beg = find_obj_beg(cur_end + 1, search_end);

   }

   live_closure->set_source(bit_to_addr(range_end));

   return complete;

 }

 ParMarkBitMap::IterationStatus

 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,

                        ParMarkBitMapClosure* dead_closure,

                        idx_t range_beg, idx_t range_end,

                        idx_t dead_range_end) const

 {

   DEBUG_ONLY(verify_bit(range_beg);)

   DEBUG_ONLY(verify_bit(range_end);)

   DEBUG_ONLY(verify_bit(dead_range_end);)

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

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

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

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

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

   idx_t cur_beg = range_beg;

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

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

     cur_beg = find_obj_beg(range_beg + 1, dead_search_end);

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

     const size_t size = obj_size(range_beg, dead_space_end);

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

   }

   while (cur_beg < range_end) {

     const idx_t cur_end = find_obj_end(cur_beg, live_search_end);

     if (cur_end >= range_end) {

       // The obj ends outside the range.

       live_closure->set_source(bit_to_addr(cur_beg));

       return incomplete;

     }

     const size_t size = obj_size(cur_beg, cur_end);

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

     if (status != incomplete) {

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

       return status;

     }

     // Look for the start of the next object.

     const idx_t dead_space_beg = cur_end + 1;

     cur_beg = find_obj_beg(dead_space_beg, dead_search_end);

     if (cur_beg > dead_space_beg) {

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

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

       const size_t size = obj_size(dead_space_beg, dead_space_end);

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

     }

   }

   live_closure->set_source(bit_to_addr(range_end));

   return complete;

 }

 #ifndef PRODUCT

 void ParMarkBitMap::reset_counters()

 {

   _cas_tries = _cas_retries = _cas_by_another = 0;

 }

 #endif  // #ifndef PRODUCT

 #ifdef ASSERT

 void ParMarkBitMap::verify_clear() const

 {

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

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

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

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

   }

 }

 #endif  // #ifdef ASSERT