Mon, 03 Aug 2009 12:59:30 -0700
6865703: G1: Parallelize hot card cache cleanup
Summary: Have the GC worker threads clear the hot card cache in parallel by having each worker thread claim a chunk of the card cache and process the cards in that chunk. The size of the chunks that each thread will claim is determined at VM initialization from the size of the card cache and the number of worker threads.
Reviewed-by: jmasa, tonyp
1 /*
2 * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 class ObjectClosure;
26 class JavaThread;
28 // A ptrQueue whose elements are "oops", pointers to object heads.
29 class ObjPtrQueue: public PtrQueue {
30 public:
31 ObjPtrQueue(PtrQueueSet* qset_, bool perm = false) :
32 PtrQueue(qset_, perm)
33 {}
34 // Apply the closure to all elements, and reset the index to make the
35 // buffer empty.
36 void apply_closure(ObjectClosure* cl);
38 // Apply the closure to all elements of "buf", down to "index" (inclusive.)
39 static void apply_closure_to_buffer(ObjectClosure* cl,
40 void** buf, size_t index, size_t sz);
42 void verify_oops_in_buffer() NOT_DEBUG_RETURN;
43 };
47 class SATBMarkQueueSet: public PtrQueueSet {
48 ObjectClosure* _closure;
49 ObjectClosure** _par_closures; // One per ParGCThread.
51 ObjPtrQueue _shared_satb_queue;
53 // Utility function to support sequential and parallel versions. If
54 // "par" is true, then "worker" is the par thread id; if "false", worker
55 // is ignored.
56 bool apply_closure_to_completed_buffer_work(bool par, int worker);
59 public:
60 SATBMarkQueueSet();
62 void initialize(Monitor* cbl_mon, Mutex* fl_lock,
63 int max_completed_queue = 0,
64 Mutex* lock = NULL);
66 static void handle_zero_index_for_thread(JavaThread* t);
68 // Apply "set_active(b)" to all thread tloq's. Should be called only
69 // with the world stopped.
70 void set_active_all_threads(bool b);
72 // Register "blk" as "the closure" for all queues. Only one such closure
73 // is allowed. The "apply_closure_to_completed_buffer" method will apply
74 // this closure to a completed buffer, and "iterate_closure_all_threads"
75 // applies it to partially-filled buffers (the latter should only be done
76 // with the world stopped).
77 void set_closure(ObjectClosure* closure);
78 // Set the parallel closures: pointer is an array of pointers to
79 // closures, one for each parallel GC thread.
80 void set_par_closure(int i, ObjectClosure* closure);
82 // If there is a registered closure for buffers, apply it to all entries
83 // in all currently-active buffers. This should only be applied at a
84 // safepoint. (Currently must not be called in parallel; this should
85 // change in the future.)
86 void iterate_closure_all_threads();
87 // Parallel version of the above.
88 void par_iterate_closure_all_threads(int worker);
90 // If there exists some completed buffer, pop it, then apply the
91 // registered closure to all its elements, and return true. If no
92 // completed buffers exist, return false.
93 bool apply_closure_to_completed_buffer() {
94 return apply_closure_to_completed_buffer_work(false, 0);
95 }
96 // Parallel version of the above.
97 bool par_apply_closure_to_completed_buffer(int worker) {
98 return apply_closure_to_completed_buffer_work(true, worker);
99 }
101 ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; }
103 // If a marking is being abandoned, reset any unprocessed log buffers.
104 void abandon_partial_marking();
106 };