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/*
* Copyright (c) 2002, 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/parallelScavengeHeap.hpp"
#include "gc_implementation/parallelScavenge/psPromotionLAB.hpp"
#include "gc_implementation/shared/mutableSpace.hpp"
#include "oops/oop.inline.hpp"
size_t PSPromotionLAB::filler_header_size;
// This is the shared initialization code. It sets up the basic pointers,
// and allows enough extra space for a filler object. We call a virtual
// method, "lab_is_valid()" to handle the different asserts the old/young
// labs require.
void PSPromotionLAB::initialize(MemRegion lab) {
assert(lab_is_valid(lab), "Sanity");
HeapWord* bottom = lab.start();
HeapWord* end = lab.end();
set_bottom(bottom);
set_end(end);
set_top(bottom);
// Initialize after VM starts up because header_size depends on compressed
// oops.
filler_header_size = align_object_size(typeArrayOopDesc::header_size(T_INT));
// We can be initialized to a zero size!
if (free() > 0) {
if (ZapUnusedHeapArea) {
debug_only(Copy::fill_to_words(top(), free()/HeapWordSize, badHeapWord));
}
// NOTE! We need to allow space for a filler object.
assert(lab.word_size() >= filler_header_size, "lab is too small");
end = end - filler_header_size;
set_end(end);
_state = needs_flush;
} else {
_state = zero_size;
}
assert(this->top() <= this->end(), "pointers out of order");
}
// Fill all remaining lab space with an unreachable object.
// The goal is to leave a contiguous parseable span of objects.
void PSPromotionLAB::flush() {
assert(_state != flushed, "Attempt to flush PLAB twice");
assert(top() <= end(), "pointers out of order");
// If we were initialized to a zero sized lab, there is
// nothing to flush
if (_state == zero_size)
return;
// PLAB's never allocate the last aligned_header_size
// so they can always fill with an array.
HeapWord* tlab_end = end() + filler_header_size;
typeArrayOop filler_oop = (typeArrayOop) top();
filler_oop->set_mark(markOopDesc::prototype());
filler_oop->set_klass(Universe::intArrayKlassObj());
const size_t array_length =
pointer_delta(tlab_end, top()) - typeArrayOopDesc::header_size(T_INT);
assert( (array_length * (HeapWordSize/sizeof(jint))) < (size_t)max_jint, "array too big in PSPromotionLAB");
filler_oop->set_length((int)(array_length * (HeapWordSize/sizeof(jint))));
#ifdef ASSERT
// Note that we actually DO NOT want to use the aligned header size!
HeapWord* elt_words = ((HeapWord*)filler_oop) + typeArrayOopDesc::header_size(T_INT);
Copy::fill_to_words(elt_words, array_length, 0xDEAABABE);
#endif
set_bottom(NULL);
set_end(NULL);
set_top(NULL);
_state = flushed;
}
bool PSPromotionLAB::unallocate_object(oop obj) {
assert(Universe::heap()->is_in(obj), "Object outside heap");
if (contains(obj)) {
HeapWord* object_end = (HeapWord*)obj + obj->size();
assert(object_end <= top(), "Object crosses promotion LAB boundary");
if (object_end == top()) {
set_top((HeapWord*)obj);
return true;
}
}
return false;
}
// Fill all remaining lab space with an unreachable object.
// The goal is to leave a contiguous parseable span of objects.
void PSOldPromotionLAB::flush() {
assert(_state != flushed, "Attempt to flush PLAB twice");
assert(top() <= end(), "pointers out of order");
if (_state == zero_size)
return;
HeapWord* obj = top();
PSPromotionLAB::flush();
assert(_start_array != NULL, "Sanity");
_start_array->allocate_block(obj);
}
#ifdef ASSERT
bool PSYoungPromotionLAB::lab_is_valid(MemRegion lab) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
MutableSpace* to_space = heap->young_gen()->to_space();
MemRegion used = to_space->used_region();
if (used.contains(lab)) {
return true;
}
return false;
}
bool PSOldPromotionLAB::lab_is_valid(MemRegion lab) {
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
assert(_start_array->covered_region().contains(lab), "Sanity");
PSOldGen* old_gen = heap->old_gen();
MemRegion used = old_gen->object_space()->used_region();
if (used.contains(lab)) {
return true;
}
return false;
}
#endif /* ASSERT */
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