Mercurial > hg > truffle
diff src/share/vm/gc_implementation/shared/mutableSpace.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | d1635bf93939 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/shared/mutableSpace.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,131 @@ +/* + * 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"); +}