Mercurial > hg > truffle
diff src/share/vm/gc_implementation/parallelScavenge/objectStartArray.cpp @ 0:a61af66fc99e jdk7-b24
Initial load
author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | c18cbe5936b8 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/parallelScavenge/objectStartArray.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,137 @@ +/* + * Copyright 2001-2005 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/_objectStartArray.cpp.incl" + +void ObjectStartArray::initialize(MemRegion reserved_region) { + // We're based on the assumption that we use the same + // size blocks as the card table. + assert((int)block_size == (int)CardTableModRefBS::card_size, "Sanity"); + assert((int)block_size <= 512, "block_size must be less than or equal to 512"); + + // Calculate how much space must be reserved + _reserved_region = reserved_region; + + size_t bytes_to_reserve = reserved_region.word_size() / block_size_in_words; + assert(bytes_to_reserve > 0, "Sanity"); + + bytes_to_reserve = + align_size_up(bytes_to_reserve, os::vm_allocation_granularity()); + + // Do not use large-pages for the backing store. The one large page region + // will be used for the heap proper. + ReservedSpace backing_store(bytes_to_reserve); + if (!backing_store.is_reserved()) { + vm_exit_during_initialization("Could not reserve space for ObjectStartArray"); + } + + // We do not commit any memory initially + if (!_virtual_space.initialize(backing_store, 0)) { + vm_exit_during_initialization("Could not commit space for ObjectStartArray"); + } + + _raw_base = (jbyte*)_virtual_space.low_boundary(); + if (_raw_base == NULL) { + vm_exit_during_initialization("Could not get raw_base address"); + } + + _offset_base = _raw_base - (size_t(reserved_region.start()) >> block_shift); + + _covered_region.set_start(reserved_region.start()); + _covered_region.set_word_size(0); + + _blocks_region.set_start((HeapWord*)_raw_base); + _blocks_region.set_word_size(0); +} + +void ObjectStartArray::set_covered_region(MemRegion mr) { + assert(_reserved_region.contains(mr), "MemRegion outside of reserved space"); + assert(_reserved_region.start() == mr.start(), "Attempt to move covered region"); + + HeapWord* low_bound = mr.start(); + HeapWord* high_bound = mr.end(); + assert((uintptr_t(low_bound) & (block_size - 1)) == 0, "heap must start at block boundary"); + assert((uintptr_t(high_bound) & (block_size - 1)) == 0, "heap must end at block boundary"); + + size_t requested_blocks_size_in_bytes = mr.word_size() / block_size_in_words; + + // Only commit memory in page sized chunks + requested_blocks_size_in_bytes = + align_size_up(requested_blocks_size_in_bytes, os::vm_page_size()); + + _covered_region = mr; + + size_t current_blocks_size_in_bytes = _blocks_region.byte_size(); + + if (requested_blocks_size_in_bytes > current_blocks_size_in_bytes) { + // Expand + size_t expand_by = requested_blocks_size_in_bytes - current_blocks_size_in_bytes; + if (!_virtual_space.expand_by(expand_by)) { + vm_exit_out_of_memory(expand_by, "object start array expansion"); + } + // Clear *only* the newly allocated region + memset(_blocks_region.end(), clean_block, expand_by); + } + + if (requested_blocks_size_in_bytes < current_blocks_size_in_bytes) { + // Shrink + size_t shrink_by = current_blocks_size_in_bytes - requested_blocks_size_in_bytes; + _virtual_space.shrink_by(shrink_by); + } + + _blocks_region.set_word_size(requested_blocks_size_in_bytes / sizeof(HeapWord)); + + assert(requested_blocks_size_in_bytes % sizeof(HeapWord) == 0, "Block table not expanded in word sized increment"); + assert(requested_blocks_size_in_bytes == _blocks_region.byte_size(), "Sanity"); + assert(block_for_addr(low_bound) == &_raw_base[0], "Checking start of map"); + assert(block_for_addr(high_bound-1) <= &_raw_base[_blocks_region.byte_size()-1], "Checking end of map"); +} + +void ObjectStartArray::reset() { + memset(_blocks_region.start(), clean_block, _blocks_region.byte_size()); +} + + +bool ObjectStartArray::object_starts_in_range(HeapWord* start_addr, + HeapWord* end_addr) const { + assert(start_addr <= end_addr, "range is wrong"); + if (start_addr > end_addr) { + return false; + } + + jbyte* start_block = block_for_addr(start_addr); + jbyte* end_block = block_for_addr(end_addr); + + for (jbyte* block = start_block; block <= end_block; block++) { + if (*block != clean_block) { + return true; + } + } + // No object starts in this slice; verify this using + // more traditional methods: + assert(object_start(end_addr - 1) <= start_addr, + "Oops an object does start in this slice?"); + return false; +}