| /* |
| * Copyright 2001-2007 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" |
| |
| void MutableSpace::initialize(MemRegion mr, bool clear_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(); |
| } |
| |
| void MutableSpace::clear() { |
| set_top(bottom()); |
| if (ZapUnusedHeapArea) mangle_unused_area(); |
| } |
| |
| // 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) const { |
| 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"); |
| } |