Tue, 26 Jan 2010 16:52:29 -0800
6920090: G1: Disable ReduceInitialCardMarks at least until 6920109 is fixed
Summary: G1 now answers "no" to the query can_elide_initializing_store_barrier() in the product build. A debug flag allows alternate behaviour in debug builds.
Reviewed-by: iveresov, tonyp
1 /*
2 * Copyright 2001-2009 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 // The Concurrent ZF Thread. Performs concurrent zero-filling.
27 class ConcurrentZFThread: public ConcurrentGCThread {
28 friend class VMStructs;
29 friend class ZeroFillRegionClosure;
31 private:
33 // Zero fill the heap region.
34 void processHeapRegion(HeapRegion* r);
36 // Stats
37 // Allocation (protected by heap lock).
38 static int _region_allocs; // Number of regions allocated
39 static int _sync_zfs; // Synchronous zero-fills +
40 static int _zf_waits; // Wait for conc zero-fill completion.
42 // Number of regions CFZ thread fills.
43 static int _regions_filled;
45 double _vtime_start; // Initial virtual time.
47 // These are static because the "print_summary_info" method is, and
48 // it currently assumes there is only one ZF thread. We'll change when
49 // we need to.
50 static double _vtime_accum; // Initial virtual time.
51 static double vtime_accum() { return _vtime_accum; }
53 // Offer yield for GC. Returns true if yield occurred.
54 bool offer_yield();
56 public:
57 // Constructor
58 ConcurrentZFThread();
60 // Main loop.
61 virtual void run();
63 // Printing
64 void print_on(outputStream* st) const;
65 void print() const;
67 // Waits until "r" has been zero-filled. Requires caller to hold the
68 // ZF_mon.
69 static void wait_for_ZF_completed(HeapRegion* r);
71 // Get or clear the current unclean region. Should be done
72 // while holding the ZF_needed_mon lock.
74 // shutdown
75 void stop();
77 // Stats
78 static void note_region_alloc() {_region_allocs++; }
79 static void note_sync_zfs() { _sync_zfs++; }
80 static void note_zf_wait() { _zf_waits++; }
81 static void note_region_filled() { _regions_filled++; }
83 static void print_summary_info();
84 };