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/*
* Copyright 2001-2008 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/_mutableSpace.cpp.incl"
MutableSpace::MutableSpace(): ImmutableSpace(), _top(NULL) {
_mangler = new MutableSpaceMangler(this);
}
MutableSpace::~MutableSpace() {
delete _mangler;
}
void MutableSpace::initialize(MemRegion mr,
bool clear_space,
bool mangle_space) {
HeapWord* bottom = mr.start();
HeapWord* end = mr.end();
assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end),
"invalid space boundaries");
set_bottom(bottom);
set_end(end);
if (clear_space) {
clear(mangle_space);
}
}
void MutableSpace::clear(bool mangle_space) {
set_top(bottom());
if (ZapUnusedHeapArea && mangle_space) {
mangle_unused_area();
}
}
#ifndef PRODUCT
void MutableSpace::check_mangled_unused_area(HeapWord* limit) {
mangler()->check_mangled_unused_area(limit);
}
void MutableSpace::check_mangled_unused_area_complete() {
mangler()->check_mangled_unused_area_complete();
}
// Mangle only the unused space that has not previously
// been mangled and that has not been allocated since being
// mangled.
void MutableSpace::mangle_unused_area() {
mangler()->mangle_unused_area();
}
void MutableSpace::mangle_unused_area_complete() {
mangler()->mangle_unused_area_complete();
}
void MutableSpace::mangle_region(MemRegion mr) {
SpaceMangler::mangle_region(mr);
}
void MutableSpace::set_top_for_allocations(HeapWord* v) {
mangler()->set_top_for_allocations(v);
}
void MutableSpace::set_top_for_allocations() {
mangler()->set_top_for_allocations(top());
}
#endif
// This version requires locking. */
HeapWord* MutableSpace::allocate(size_t size) {
assert(Heap_lock->owned_by_self() ||
(SafepointSynchronize::is_at_safepoint() &&
Thread::current()->is_VM_thread()),
"not locked");
HeapWord* obj = top();
if (pointer_delta(end(), obj) >= size) {
HeapWord* new_top = obj + size;
set_top(new_top);
assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
"checking alignment");
return obj;
} else {
return NULL;
}
}
// This version is lock-free.
HeapWord* MutableSpace::cas_allocate(size_t size) {
do {
HeapWord* obj = top();
if (pointer_delta(end(), obj) >= size) {
HeapWord* new_top = obj + size;
HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
// result can be one of two:
// the old top value: the exchange succeeded
// otherwise: the new value of the top is returned.
if (result != obj) {
continue; // another thread beat us to the allocation, try again
}
assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
"checking alignment");
return obj;
} else {
return NULL;
}
} while (true);
}
// Try to deallocate previous allocation. Returns true upon success.
bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {
HeapWord* expected_top = obj + size;
return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top;
}
void MutableSpace::oop_iterate(OopClosure* cl) {
HeapWord* obj_addr = bottom();
HeapWord* t = top();
// Could call objects iterate, but this is easier.
while (obj_addr < t) {
obj_addr += oop(obj_addr)->oop_iterate(cl);
}
}
void MutableSpace::object_iterate(ObjectClosure* cl) {
HeapWord* p = bottom();
while (p < top()) {
cl->do_object(oop(p));
p += oop(p)->size();
}
}
void MutableSpace::print_short() const { print_short_on(tty); }
void MutableSpace::print_short_on( outputStream* st) const {
st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,
(int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));
}
void MutableSpace::print() const { print_on(tty); }
void MutableSpace::print_on(outputStream* st) const {
MutableSpace::print_short_on(st);
st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",
bottom(), top(), end());
}
void MutableSpace::verify(bool allow_dirty) {
HeapWord* p = bottom();
HeapWord* t = top();
HeapWord* prev_p = NULL;
while (p < t) {
oop(p)->verify();
prev_p = p;
p += oop(p)->size();
}
guarantee(p == top(), "end of last object must match end of space");
}
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