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/*
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* Copyright 2001-2005 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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*/
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# include "incls/_precompiled.incl"
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# include "incls/_objectStartArray.cpp.incl"
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void ObjectStartArray::initialize(MemRegion reserved_region) {
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// We're based on the assumption that we use the same
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// size blocks as the card table.
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assert((int)block_size == (int)CardTableModRefBS::card_size, "Sanity");
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assert((int)block_size <= 512, "block_size must be less than or equal to 512");
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// Calculate how much space must be reserved
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_reserved_region = reserved_region;
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size_t bytes_to_reserve = reserved_region.word_size() / block_size_in_words;
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assert(bytes_to_reserve > 0, "Sanity");
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bytes_to_reserve =
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align_size_up(bytes_to_reserve, os::vm_allocation_granularity());
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// Do not use large-pages for the backing store. The one large page region
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// will be used for the heap proper.
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ReservedSpace backing_store(bytes_to_reserve);
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if (!backing_store.is_reserved()) {
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vm_exit_during_initialization("Could not reserve space for ObjectStartArray");
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}
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// We do not commit any memory initially
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if (!_virtual_space.initialize(backing_store, 0)) {
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vm_exit_during_initialization("Could not commit space for ObjectStartArray");
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}
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_raw_base = (jbyte*)_virtual_space.low_boundary();
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if (_raw_base == NULL) {
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vm_exit_during_initialization("Could not get raw_base address");
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}
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_offset_base = _raw_base - (size_t(reserved_region.start()) >> block_shift);
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_covered_region.set_start(reserved_region.start());
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_covered_region.set_word_size(0);
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_blocks_region.set_start((HeapWord*)_raw_base);
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_blocks_region.set_word_size(0);
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}
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void ObjectStartArray::set_covered_region(MemRegion mr) {
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assert(_reserved_region.contains(mr), "MemRegion outside of reserved space");
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assert(_reserved_region.start() == mr.start(), "Attempt to move covered region");
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HeapWord* low_bound = mr.start();
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HeapWord* high_bound = mr.end();
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assert((uintptr_t(low_bound) & (block_size - 1)) == 0, "heap must start at block boundary");
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assert((uintptr_t(high_bound) & (block_size - 1)) == 0, "heap must end at block boundary");
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size_t requested_blocks_size_in_bytes = mr.word_size() / block_size_in_words;
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// Only commit memory in page sized chunks
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requested_blocks_size_in_bytes =
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align_size_up(requested_blocks_size_in_bytes, os::vm_page_size());
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_covered_region = mr;
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size_t current_blocks_size_in_bytes = _blocks_region.byte_size();
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if (requested_blocks_size_in_bytes > current_blocks_size_in_bytes) {
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// Expand
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size_t expand_by = requested_blocks_size_in_bytes - current_blocks_size_in_bytes;
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if (!_virtual_space.expand_by(expand_by)) {
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vm_exit_out_of_memory(expand_by, "object start array expansion");
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}
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// Clear *only* the newly allocated region
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memset(_blocks_region.end(), clean_block, expand_by);
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}
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if (requested_blocks_size_in_bytes < current_blocks_size_in_bytes) {
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// Shrink
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size_t shrink_by = current_blocks_size_in_bytes - requested_blocks_size_in_bytes;
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_virtual_space.shrink_by(shrink_by);
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}
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_blocks_region.set_word_size(requested_blocks_size_in_bytes / sizeof(HeapWord));
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assert(requested_blocks_size_in_bytes % sizeof(HeapWord) == 0, "Block table not expanded in word sized increment");
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assert(requested_blocks_size_in_bytes == _blocks_region.byte_size(), "Sanity");
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assert(block_for_addr(low_bound) == &_raw_base[0], "Checking start of map");
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assert(block_for_addr(high_bound-1) <= &_raw_base[_blocks_region.byte_size()-1], "Checking end of map");
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}
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void ObjectStartArray::reset() {
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memset(_blocks_region.start(), clean_block, _blocks_region.byte_size());
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}
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bool ObjectStartArray::object_starts_in_range(HeapWord* start_addr,
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HeapWord* end_addr) const {
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assert(start_addr <= end_addr, "range is wrong");
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if (start_addr > end_addr) {
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return false;
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}
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jbyte* start_block = block_for_addr(start_addr);
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jbyte* end_block = block_for_addr(end_addr);
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for (jbyte* block = start_block; block <= end_block; block++) {
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if (*block != clean_block) {
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return true;
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}
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}
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// No object starts in this slice; verify this using
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// more traditional methods:
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assert(object_start(end_addr - 1) <= start_addr,
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"Oops an object does start in this slice?");
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return false;
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}
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