duke@435: /*
stefank@2314:  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "gc_implementation/parallelScavenge/objectStartArray.hpp"
stefank@2314: #include "memory/allocation.inline.hpp"
stefank@2314: #include "memory/cardTableModRefBS.hpp"
stefank@2314: #include "oops/oop.inline.hpp"
stefank@2314: #include "runtime/java.hpp"
duke@435: 
duke@435: void ObjectStartArray::initialize(MemRegion reserved_region) {
duke@435:   // We're based on the assumption that we use the same
duke@435:   // size blocks as the card table.
duke@435:   assert((int)block_size == (int)CardTableModRefBS::card_size, "Sanity");
duke@435:   assert((int)block_size <= 512, "block_size must be less than or equal to 512");
duke@435: 
duke@435:   // Calculate how much space must be reserved
duke@435:   _reserved_region = reserved_region;
duke@435: 
duke@435:   size_t bytes_to_reserve = reserved_region.word_size() / block_size_in_words;
duke@435:   assert(bytes_to_reserve > 0, "Sanity");
duke@435: 
duke@435:   bytes_to_reserve =
duke@435:     align_size_up(bytes_to_reserve, os::vm_allocation_granularity());
duke@435: 
duke@435:   // Do not use large-pages for the backing store. The one large page region
duke@435:   // will be used for the heap proper.
duke@435:   ReservedSpace backing_store(bytes_to_reserve);
duke@435:   if (!backing_store.is_reserved()) {
duke@435:     vm_exit_during_initialization("Could not reserve space for ObjectStartArray");
duke@435:   }
duke@435: 
duke@435:   // We do not commit any memory initially
duke@435:   if (!_virtual_space.initialize(backing_store, 0)) {
duke@435:     vm_exit_during_initialization("Could not commit space for ObjectStartArray");
duke@435:   }
duke@435: 
duke@435:   _raw_base = (jbyte*)_virtual_space.low_boundary();
duke@435:   if (_raw_base == NULL) {
duke@435:     vm_exit_during_initialization("Could not get raw_base address");
duke@435:   }
duke@435: 
duke@435:   _offset_base = _raw_base - (size_t(reserved_region.start()) >> block_shift);
duke@435: 
duke@435:   _covered_region.set_start(reserved_region.start());
duke@435:   _covered_region.set_word_size(0);
duke@435: 
duke@435:   _blocks_region.set_start((HeapWord*)_raw_base);
duke@435:   _blocks_region.set_word_size(0);
duke@435: }
duke@435: 
duke@435: void ObjectStartArray::set_covered_region(MemRegion mr) {
duke@435:   assert(_reserved_region.contains(mr), "MemRegion outside of reserved space");
duke@435:   assert(_reserved_region.start() == mr.start(), "Attempt to move covered region");
duke@435: 
duke@435:   HeapWord* low_bound  = mr.start();
duke@435:   HeapWord* high_bound = mr.end();
duke@435:   assert((uintptr_t(low_bound)  & (block_size - 1))  == 0, "heap must start at block boundary");
duke@435:   assert((uintptr_t(high_bound) & (block_size - 1))  == 0, "heap must end at block boundary");
duke@435: 
duke@435:   size_t requested_blocks_size_in_bytes = mr.word_size() / block_size_in_words;
duke@435: 
duke@435:   // Only commit memory in page sized chunks
duke@435:   requested_blocks_size_in_bytes =
duke@435:     align_size_up(requested_blocks_size_in_bytes, os::vm_page_size());
duke@435: 
duke@435:   _covered_region = mr;
duke@435: 
duke@435:   size_t current_blocks_size_in_bytes = _blocks_region.byte_size();
duke@435: 
duke@435:   if (requested_blocks_size_in_bytes > current_blocks_size_in_bytes) {
duke@435:     // Expand
duke@435:     size_t expand_by = requested_blocks_size_in_bytes - current_blocks_size_in_bytes;
duke@435:     if (!_virtual_space.expand_by(expand_by)) {
duke@435:       vm_exit_out_of_memory(expand_by, "object start array expansion");
duke@435:     }
duke@435:     // Clear *only* the newly allocated region
duke@435:     memset(_blocks_region.end(), clean_block, expand_by);
duke@435:   }
duke@435: 
duke@435:   if (requested_blocks_size_in_bytes < current_blocks_size_in_bytes) {
duke@435:     // Shrink
duke@435:     size_t shrink_by = current_blocks_size_in_bytes - requested_blocks_size_in_bytes;
duke@435:     _virtual_space.shrink_by(shrink_by);
duke@435:   }
duke@435: 
duke@435:   _blocks_region.set_word_size(requested_blocks_size_in_bytes / sizeof(HeapWord));
duke@435: 
duke@435:   assert(requested_blocks_size_in_bytes % sizeof(HeapWord) == 0, "Block table not expanded in word sized increment");
duke@435:   assert(requested_blocks_size_in_bytes == _blocks_region.byte_size(), "Sanity");
duke@435:   assert(block_for_addr(low_bound) == &_raw_base[0], "Checking start of map");
duke@435:   assert(block_for_addr(high_bound-1) <= &_raw_base[_blocks_region.byte_size()-1], "Checking end of map");
duke@435: }
duke@435: 
duke@435: void ObjectStartArray::reset() {
duke@435:   memset(_blocks_region.start(), clean_block, _blocks_region.byte_size());
duke@435: }
duke@435: 
duke@435: 
duke@435: bool ObjectStartArray::object_starts_in_range(HeapWord* start_addr,
duke@435:                                               HeapWord* end_addr) const {
duke@435:   assert(start_addr <= end_addr, "range is wrong");
duke@435:   if (start_addr > end_addr) {
duke@435:     return false;
duke@435:   }
duke@435: 
duke@435:   jbyte* start_block = block_for_addr(start_addr);
duke@435:   jbyte* end_block = block_for_addr(end_addr);
duke@435: 
duke@435:   for (jbyte* block = start_block; block <= end_block; block++) {
duke@435:     if (*block != clean_block) {
duke@435:       return true;
duke@435:     }
duke@435:   }
duke@435:   // No object starts in this slice; verify this using
duke@435:   // more traditional methods:
duke@435:   assert(object_start(end_addr - 1) <= start_addr,
duke@435:          "Oops an object does start in this slice?");
duke@435:   return false;
duke@435: }