jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.cpp@1fdb98a17101 (annotated)

src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.cpp@1fdb98a17101 (annotated)

src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.cpp

Sat, 19 Jul 2008 17:38:22 -0400

author: coleenp
date: Sat, 19 Jul 2008 17:38:22 -0400
changeset 672: 1fdb98a17101
parent 631: d1605aabd0a1
child 1907: c18cbe5936b8
permissions: -rw-r--r--

6716785: implicit null checks not triggering with CompressedOops
Summary: allocate alignment-sized page(s) below java heap so that memory accesses at heap_base+1page give signal and cause an implicit null check
Reviewed-by: kvn, jmasa, phh, jcoomes

 /*
  * Copyright 2005-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 # include "incls/_precompiled.incl"
 # include "incls/_parMarkBitMap.cpp.incl"
 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

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.cpp@1fdb98a17101 (annotated)

src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.cpp