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src/share/vm/gc_implementation/shared/mutableSpace.cpp@d1635bf93939 (annotated)

src/share/vm/gc_implementation/shared/mutableSpace.cpp

Mon, 09 Jun 2008 07:18:59 -0700

author

iveresov

date

Mon, 09 Jun 2008 07:18:59 -0700

changeset 625

d1635bf93939

parent 435

a61af66fc99e

child 631

d1605aabd0a1

child 698

12eea04c8b06

permissions

-rw-r--r--

6711930: NUMA allocator: ParOld can create a hole less than minimal object size in the lgrp chunk
Summary: The fix takes care of three issues that can create a hole less a minimal object in the lgrp chunk
Reviewed-by: ysr, apetrusenko

duke@435	1	/*
duke@435	2	* Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	# include "incls/_precompiled.incl"
duke@435	26	# include "incls/_mutableSpace.cpp.incl"
duke@435	27
duke@435	28	void MutableSpace::initialize(MemRegion mr, bool clear_space) {
duke@435	29	HeapWord* bottom = mr.start();
duke@435	30	HeapWord* end = mr.end();
duke@435	31
duke@435	32	assert(Universe::on_page_boundary(bottom) && Universe::on_page_boundary(end),
duke@435	33	"invalid space boundaries");
duke@435	34	set_bottom(bottom);
duke@435	35	set_end(end);
duke@435	36
duke@435	37	if (clear_space) clear();
duke@435	38	}
duke@435	39
duke@435	40	void MutableSpace::clear() {
duke@435	41	set_top(bottom());
duke@435	42	if (ZapUnusedHeapArea) mangle_unused_area();
duke@435	43	}
duke@435	44
duke@435	45	// This version requires locking. */
duke@435	46	HeapWord* MutableSpace::allocate(size_t size) {
duke@435	47	assert(Heap_lock->owned_by_self() ||
duke@435	48	(SafepointSynchronize::is_at_safepoint() &&
duke@435	49	Thread::current()->is_VM_thread()),
duke@435	50	"not locked");
duke@435	51	HeapWord* obj = top();
duke@435	52	if (pointer_delta(end(), obj) >= size) {
duke@435	53	HeapWord* new_top = obj + size;
duke@435	54	set_top(new_top);
duke@435	55	assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
duke@435	56	"checking alignment");
duke@435	57	return obj;
duke@435	58	} else {
duke@435	59	return NULL;
duke@435	60	}
duke@435	61	}
duke@435	62
duke@435	63	// This version is lock-free.
duke@435	64	HeapWord* MutableSpace::cas_allocate(size_t size) {
duke@435	65	do {
duke@435	66	HeapWord* obj = top();
duke@435	67	if (pointer_delta(end(), obj) >= size) {
duke@435	68	HeapWord* new_top = obj + size;
duke@435	69	HeapWord* result = (HeapWord*)Atomic::cmpxchg_ptr(new_top, top_addr(), obj);
duke@435	70	// result can be one of two:
duke@435	71	// the old top value: the exchange succeeded
duke@435	72	// otherwise: the new value of the top is returned.
duke@435	73	if (result != obj) {
duke@435	74	continue; // another thread beat us to the allocation, try again
duke@435	75	}
duke@435	76	assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
duke@435	77	"checking alignment");
duke@435	78	return obj;
duke@435	79	} else {
duke@435	80	return NULL;
duke@435	81	}
duke@435	82	} while (true);
duke@435	83	}
duke@435	84
duke@435	85	// Try to deallocate previous allocation. Returns true upon success.
duke@435	86	bool MutableSpace::cas_deallocate(HeapWord *obj, size_t size) {
duke@435	87	HeapWord* expected_top = obj + size;
duke@435	88	return (HeapWord*)Atomic::cmpxchg_ptr(obj, top_addr(), expected_top) == expected_top;
duke@435	89	}
duke@435	90
duke@435	91	void MutableSpace::oop_iterate(OopClosure* cl) {
duke@435	92	HeapWord* obj_addr = bottom();
duke@435	93	HeapWord* t = top();
duke@435	94	// Could call objects iterate, but this is easier.
duke@435	95	while (obj_addr < t) {
duke@435	96	obj_addr += oop(obj_addr)->oop_iterate(cl);
duke@435	97	}
duke@435	98	}
duke@435	99
duke@435	100	void MutableSpace::object_iterate(ObjectClosure* cl) {
duke@435	101	HeapWord* p = bottom();
duke@435	102	while (p < top()) {
duke@435	103	cl->do_object(oop(p));
duke@435	104	p += oop(p)->size();
duke@435	105	}
duke@435	106	}
duke@435	107
duke@435	108	void MutableSpace::print_short() const { print_short_on(tty); }
duke@435	109	void MutableSpace::print_short_on( outputStream* st) const {
duke@435	110	st->print(" space " SIZE_FORMAT "K, %d%% used", capacity_in_bytes() / K,
duke@435	111	(int) ((double) used_in_bytes() * 100 / capacity_in_bytes()));
duke@435	112	}
duke@435	113
duke@435	114	void MutableSpace::print() const { print_on(tty); }
duke@435	115	void MutableSpace::print_on(outputStream* st) const {
duke@435	116	MutableSpace::print_short_on(st);
duke@435	117	st->print_cr(" [" INTPTR_FORMAT "," INTPTR_FORMAT "," INTPTR_FORMAT ")",
duke@435	118	bottom(), top(), end());
duke@435	119	}
duke@435	120
iveresov@625	121	void MutableSpace::verify(bool allow_dirty) {
duke@435	122	HeapWord* p = bottom();
duke@435	123	HeapWord* t = top();
duke@435	124	HeapWord* prev_p = NULL;
duke@435	125	while (p < t) {
duke@435	126	oop(p)->verify();
duke@435	127	prev_p = p;
duke@435	128	p += oop(p)->size();
duke@435	129	}
duke@435	130	guarantee(p == top(), "end of last object must match end of space");
duke@435	131	}