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src/share/vm/gc_implementation/concurrentMarkSweep/freeChunk.cpp@c96030fff130 (annotated)

src/share/vm/gc_implementation/concurrentMarkSweep/freeChunk.cpp

Thu, 20 Nov 2008 16:56:09 -0800

author

ysr

date

Thu, 20 Nov 2008 16:56:09 -0800

changeset 888

c96030fff130

parent 631

d1605aabd0a1

child 1580

e018e6884bd8

permissions

-rw-r--r--

6684579: SoftReference processing can be made more efficient
Summary: For current soft-ref clearing policies, we can decide at marking time if a soft-reference will definitely not be cleared, postponing the decision of whether it will definitely be cleared to the final reference processing phase. This can be especially beneficial in the case of concurrent collectors where the marking is usually concurrent but reference processing is usually not.
Reviewed-by: jmasa

duke@435	1	/*
xdono@631	2	* Copyright 2001-2008 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/_freeChunk.cpp.incl"
duke@435	27
duke@435	28	#ifndef PRODUCT
duke@435	29
duke@435	30	#define baadbabeHeapWord badHeapWordVal
duke@435	31	#define deadbeefHeapWord 0xdeadbeef
duke@435	32
duke@435	33	size_t const FreeChunk::header_size() {
duke@435	34	return sizeof(FreeChunk)/HeapWordSize;
duke@435	35	}
duke@435	36
duke@435	37	void FreeChunk::mangleAllocated(size_t size) {
duke@435	38	// mangle all but the header of a just-allocated block
duke@435	39	// of storage
duke@435	40	assert(size >= MinChunkSize, "smallest size of object");
duke@435	41	// we can't assert that _size == size because this may be an
duke@435	42	// allocation out of a linear allocation block
duke@435	43	assert(sizeof(FreeChunk) % HeapWordSize == 0,
duke@435	44	"shouldn't write beyond chunk");
duke@435	45	HeapWord* addr = (HeapWord*)this;
duke@435	46	size_t hdr = header_size();
duke@435	47	Copy::fill_to_words(addr + hdr, size - hdr, baadbabeHeapWord);
duke@435	48	}
duke@435	49
coleenp@622	50	void FreeChunk::mangleFreed(size_t sz) {
duke@435	51	assert(baadbabeHeapWord != deadbeefHeapWord, "Need distinct patterns");
duke@435	52	// mangle all but the header of a just-freed block of storage
duke@435	53	// just prior to passing it to the storage dictionary
coleenp@622	54	assert(sz >= MinChunkSize, "smallest size of object");
coleenp@622	55	assert(sz == size(), "just checking");
duke@435	56	HeapWord* addr = (HeapWord*)this;
duke@435	57	size_t hdr = header_size();
coleenp@622	58	Copy::fill_to_words(addr + hdr, sz - hdr, deadbeefHeapWord);
duke@435	59	}
duke@435	60
duke@435	61	void FreeChunk::verifyList() const {
duke@435	62	FreeChunk* nextFC = next();
duke@435	63	if (nextFC != NULL) {
duke@435	64	assert(this == nextFC->prev(), "broken chain");
duke@435	65	assert(size() == nextFC->size(), "wrong size");
duke@435	66	nextFC->verifyList();
duke@435	67	}
duke@435	68	}
duke@435	69	#endif