duke@435: /*
duke@435:  * Copyright 2001-2007 Sun Microsystems, Inc.  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:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: # include "incls/_precompiled.incl"
duke@435: # include "incls/_mutableSpace.cpp.incl"
duke@435: 
jmasa@698: MutableSpace::MutableSpace(): ImmutableSpace(), _top(NULL) {
jmasa@698:   _mangler = new MutableSpaceMangler(this);
jmasa@698: }
jmasa@698: 
jmasa@698: MutableSpace::~MutableSpace() {
jmasa@698:   delete _mangler;
jmasa@698: }
jmasa@698: 
jmasa@698: void MutableSpace::initialize(MemRegion mr,
jmasa@698:                               bool clear_space,
jmasa@698:                               bool mangle_space) {
duke@435:   HeapWord* bottom = mr.start();
duke@435:   HeapWord* end    = mr.end();
duke@435: 
duke@435:   assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end),
duke@435:          "invalid space boundaries");
duke@435:   set_bottom(bottom);
duke@435:   set_end(end);
duke@435: 
jmasa@698:   if (clear_space) {
jmasa@698:     clear(mangle_space);
jmasa@698:   }
duke@435: }
duke@435: 
jmasa@698: void MutableSpace::clear(bool mangle_space) {
duke@435:   set_top(bottom());
jmasa@698:   if (ZapUnusedHeapArea && mangle_space) {
jmasa@698:     mangle_unused_area();
jmasa@698:   }
duke@435: }
duke@435: 
jmasa@698: #ifndef PRODUCT
jmasa@698: void MutableSpace::check_mangled_unused_area(HeapWord* limit) {
jmasa@698:   mangler()->check_mangled_unused_area(limit);
jmasa@698: }
jmasa@698: 
jmasa@698: void MutableSpace::check_mangled_unused_area_complete() {
jmasa@698:   mangler()->check_mangled_unused_area_complete();
jmasa@698: }
jmasa@698: 
jmasa@698: // Mangle only the unused space that has not previously
jmasa@698: // been mangled and that has not been allocated since being
jmasa@698: // mangled.
jmasa@698: void MutableSpace::mangle_unused_area() {
jmasa@698:   mangler()->mangle_unused_area();
jmasa@698: }
jmasa@698: 
jmasa@698: void MutableSpace::mangle_unused_area_complete() {
jmasa@698:   mangler()->mangle_unused_area_complete();
jmasa@698: }
jmasa@698: 
jmasa@698: void MutableSpace::mangle_region(MemRegion mr) {
jmasa@698:   SpaceMangler::mangle_region(mr);
jmasa@698: }
jmasa@698: 
jmasa@698: void MutableSpace::set_top_for_allocations(HeapWord* v) {
jmasa@698:   mangler()->set_top_for_allocations(v);
jmasa@698: }
jmasa@698: 
jmasa@698: void MutableSpace::set_top_for_allocations() {
jmasa@698:   mangler()->set_top_for_allocations(top());
jmasa@698: }
jmasa@698: #endif
jmasa@698: 
duke@435: // This version requires locking. */
duke@435: HeapWord* MutableSpace::allocate(size_t size) {
duke@435:   assert(Heap_lock->owned_by_self() ||
duke@435:          (SafepointSynchronize::is_at_safepoint() &&
duke@435:           Thread::current()->is_VM_thread()),
duke@435:          "not locked");
duke@435:   HeapWord* obj = top();
duke@435:   if (pointer_delta(end(), obj) >= size) {
duke@435:     HeapWord* new_top = obj + size;
duke@435:     set_top(new_top);
duke@435:     assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
duke@435:            "checking alignment");
duke@435:     return obj;
duke@435:   } else {
duke@435:     return NULL;
duke@435:   }
duke@435: }
duke@435: 
duke@435: // This version is lock-free.
duke@435: HeapWord* MutableSpace::cas_allocate(size_t size) {
duke@435:   do {
duke@435:     HeapWord* obj = top();
duke@435:     if (pointer_delta(end(), obj) >= size) {
duke@435:       HeapWord* new_top = obj + size;
duke@435:       HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
duke@435:       // result can be one of two:
duke@435:       //  the old top value: the exchange succeeded
duke@435:       //  otherwise: the new value of the top is returned.
duke@435:       if (result != obj) {
duke@435:         continue; // another thread beat us to the allocation, try again
duke@435:       }
duke@435:       assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
duke@435:              "checking alignment");
duke@435:       return obj;
duke@435:     } else {
duke@435:       return NULL;
duke@435:     }
duke@435:   } while (true);
duke@435: }
duke@435: 
duke@435: // Try to deallocate previous allocation. Returns true upon success.
duke@435: bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {
duke@435:   HeapWord* expected_top = obj + size;
duke@435:   return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top;
duke@435: }
duke@435: 
duke@435: void MutableSpace::oop_iterate(OopClosure* cl) {
duke@435:   HeapWord* obj_addr = bottom();
duke@435:   HeapWord* t = top();
duke@435:   // Could call objects iterate, but this is easier.
duke@435:   while (obj_addr < t) {
duke@435:     obj_addr += oop(obj_addr)->oop_iterate(cl);
duke@435:   }
duke@435: }
duke@435: 
duke@435: void MutableSpace::object_iterate(ObjectClosure* cl) {
duke@435:   HeapWord* p = bottom();
duke@435:   while (p < top()) {
duke@435:     cl->do_object(oop(p));
duke@435:     p += oop(p)->size();
duke@435:   }
duke@435: }
duke@435: 
duke@435: void MutableSpace::print_short() const { print_short_on(tty); }
duke@435: void MutableSpace::print_short_on( outputStream* st) const {
duke@435:   st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,
duke@435:             (int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));
duke@435: }
duke@435: 
duke@435: void MutableSpace::print() const { print_on(tty); }
duke@435: void MutableSpace::print_on(outputStream* st) const {
duke@435:   MutableSpace::print_short_on(st);
duke@435:   st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",
duke@435:                  bottom(), top(), end());
duke@435: }
duke@435: 
iveresov@625: void MutableSpace::verify(bool allow_dirty) {
duke@435:   HeapWord* p = bottom();
duke@435:   HeapWord* t = top();
duke@435:   HeapWord* prev_p = NULL;
duke@435:   while (p < t) {
duke@435:     oop(p)->verify();
duke@435:     prev_p = p;
duke@435:     p += oop(p)->size();
duke@435:   }
duke@435:   guarantee(p == top(), "end of last object must match end of space");
duke@435: }