8214259: Implementation: JEP 189: Shenandoah: A Low-Pause-Time Garbage Collector (Experimental)
Reviewed-by: kvn, roland, shade, coleenp, lmesnik, pliden, jgeorge, ihse, erikj
Contributed-by: Christine Flood <chf@redhat.com>, Aleksey Shipilev <shade@redhat.com>, Roland Westrelin <rwestrel@redhat.com>, Zhenygu Gu <zgu@redhat.com>, Andrew Haley <aph@redhat.com>, Andrew Dinn <adinn@redhat.com>, Mario Torre <mtorre@redhat.com>, Roman Kennke <rkennke@redhat.com>
/*
* Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved.
*
* 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUP_HPP
#define SHARE_VM_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUP_HPP
#include "classfile/javaClasses.inline.hpp"
#include "gc/shared/stringdedup/stringDedup.hpp"
#include "memory/iterator.hpp"
class ShenandoahStringDedup : public StringDedup {
public:
// Initialize string deduplication.
static void initialize();
// Enqueue a string to worker's local string dedup queue
static void enqueue_candidate(oop java_string);
// Deduplicate a string, the call is lock-free
static void deduplicate(oop java_string);
static void parallel_oops_do(OopClosure* cl, uint worker_id);
static void oops_do_slow(OopClosure* cl);
// Parallel cleanup string dedup queues/table
static void parallel_cleanup();
static inline bool is_candidate(oop obj) {
return java_lang_String::is_instance_inlined(obj) &&
java_lang_String::value(obj) != NULL;
}
private:
static void unlink_or_oops_do(BoolObjectClosure* is_alive,
OopClosure* keep_alive,
bool allow_resize_and_rehash);
};
#endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHSTRINGDEDUP_HPP