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src/share/vm/gc_implementation/g1/g1OopClosures.cpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/g1OopClosures.cpp

Fri, 10 Oct 2014 15:51:58 +0200

author

tschatzl

date

Fri, 10 Oct 2014 15:51:58 +0200

changeset 7257

e7d0505c8a30

parent 6939

cd43876f692e

permissions

-rw-r--r--

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation.
aoqi@0	8	*
aoqi@0	9	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	12	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	13	* accompanied this code).
aoqi@0	14	*
aoqi@0	15	* You should have received a copy of the GNU General Public License version
aoqi@0	16	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	18	*
aoqi@0	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	20	* or visit www.oracle.com if you need additional information or have any
aoqi@0	21	* questions.
aoqi@0	22	*
aoqi@0	23	*/
aoqi@0	24
aoqi@0	25	#include "precompiled.hpp"
aoqi@0	26	#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
aoqi@0	27	#include "gc_implementation/g1/g1OopClosures.inline.hpp"
tschatzl@6939	28	#include "gc_implementation/g1/g1ParScanThreadState.hpp"
aoqi@0	29
aoqi@0	30	G1ParCopyHelper::G1ParCopyHelper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state) :
aoqi@0	31	G1ParClosureSuper(g1, par_scan_state), _scanned_klass(NULL),
aoqi@0	32	_cm(_g1->concurrent_mark()) {}
tschatzl@6937	33
tschatzl@6939	34	G1ParClosureSuper::G1ParClosureSuper(G1CollectedHeap* g1) :
tschatzl@6939	35	_g1(g1), _par_scan_state(NULL), _worker_id(UINT_MAX) { }
tschatzl@6939	36
tschatzl@6937	37	G1ParClosureSuper::G1ParClosureSuper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state) :
tschatzl@6939	38	_g1(g1), _par_scan_state(NULL),
tschatzl@6939	39	_worker_id(UINT_MAX) {
tschatzl@6939	40	set_par_scan_thread_state(par_scan_state);
tschatzl@6939	41	}
tschatzl@6939	42
tschatzl@6939	43	void G1ParClosureSuper::set_par_scan_thread_state(G1ParScanThreadState* par_scan_state) {
tschatzl@6939	44	assert(_par_scan_state == NULL, "_par_scan_state must only be set once");
tschatzl@6939	45	assert(par_scan_state != NULL, "Must set par_scan_state to non-NULL.");
tschatzl@6939	46
tschatzl@6939	47	_par_scan_state = par_scan_state;
tschatzl@6939	48	_worker_id = par_scan_state->queue_num();
tschatzl@6939	49
tschatzl@6939	50	assert(_worker_id < MAX2((uint)ParallelGCThreads, 1u),
tschatzl@6939	51	err_msg("The given worker id %u must be less than the number of threads %u", _worker_id, MAX2((uint)ParallelGCThreads, 1u)));
tschatzl@6939	52	}