Tue, 13 Apr 2010 13:52:10 -0700
6858496: Clear all SoftReferences before an out-of-memory due to GC overhead limit.
Summary: Ensure a full GC that clears SoftReferences before throwing an out-of-memory
Reviewed-by: ysr, jcoomes
ysr@777 | 1 | /* |
xdono@1279 | 2 | * Copyright 2001-2009 Sun Microsystems, Inc. All Rights Reserved. |
ysr@777 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
ysr@777 | 4 | * |
ysr@777 | 5 | * This code is free software; you can redistribute it and/or modify it |
ysr@777 | 6 | * under the terms of the GNU General Public License version 2 only, as |
ysr@777 | 7 | * published by the Free Software Foundation. |
ysr@777 | 8 | * |
ysr@777 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
ysr@777 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
ysr@777 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
ysr@777 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
ysr@777 | 13 | * accompanied this code). |
ysr@777 | 14 | * |
ysr@777 | 15 | * You should have received a copy of the GNU General Public License version |
ysr@777 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
ysr@777 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
ysr@777 | 18 | * |
ysr@777 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
ysr@777 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
ysr@777 | 21 | * have any questions. |
ysr@777 | 22 | * |
ysr@777 | 23 | */ |
ysr@777 | 24 | |
ysr@777 | 25 | // The Concurrent Mark GC Thread (could be several in the future). |
ysr@777 | 26 | // This is copied from the Concurrent Mark Sweep GC Thread |
ysr@777 | 27 | // Still under construction. |
ysr@777 | 28 | |
ysr@777 | 29 | class ConcurrentMark; |
ysr@777 | 30 | |
ysr@777 | 31 | class ConcurrentMarkThread: public ConcurrentGCThread { |
ysr@777 | 32 | friend class VMStructs; |
ysr@777 | 33 | |
ysr@777 | 34 | double _vtime_start; // Initial virtual time. |
ysr@777 | 35 | double _vtime_accum; // Accumulated virtual time. |
ysr@777 | 36 | |
ysr@777 | 37 | double _vtime_mark_accum; |
ysr@777 | 38 | double _vtime_count_accum; |
ysr@777 | 39 | |
ysr@777 | 40 | public: |
ysr@777 | 41 | virtual void run(); |
ysr@777 | 42 | |
ysr@777 | 43 | private: |
ysr@777 | 44 | ConcurrentMark* _cm; |
tonyp@1794 | 45 | volatile bool _started; |
tonyp@1794 | 46 | volatile bool _in_progress; |
ysr@777 | 47 | |
ysr@777 | 48 | void sleepBeforeNextCycle(); |
ysr@777 | 49 | |
ysr@777 | 50 | static SurrogateLockerThread* _slt; |
ysr@777 | 51 | |
ysr@777 | 52 | public: |
ysr@777 | 53 | // Constructor |
ysr@777 | 54 | ConcurrentMarkThread(ConcurrentMark* cm); |
ysr@777 | 55 | |
ysr@777 | 56 | static void makeSurrogateLockerThread(TRAPS); |
ysr@777 | 57 | static SurrogateLockerThread* slt() { return _slt; } |
ysr@777 | 58 | |
ysr@777 | 59 | // Printing |
tonyp@1454 | 60 | void print_on(outputStream* st) const; |
tonyp@1454 | 61 | void print() const; |
ysr@777 | 62 | |
ysr@777 | 63 | // Total virtual time so far. |
ysr@777 | 64 | double vtime_accum(); |
ysr@777 | 65 | // Marking virtual time so far |
ysr@777 | 66 | double vtime_mark_accum(); |
ysr@777 | 67 | // Counting virtual time so far. |
ysr@777 | 68 | double vtime_count_accum() { return _vtime_count_accum; } |
ysr@777 | 69 | |
tonyp@1794 | 70 | ConcurrentMark* cm() { return _cm; } |
ysr@777 | 71 | |
tonyp@1794 | 72 | void set_started() { _started = true; } |
tonyp@1794 | 73 | void clear_started() { _started = false; } |
tonyp@1794 | 74 | bool started() { return _started; } |
ysr@777 | 75 | |
tonyp@1794 | 76 | void set_in_progress() { _in_progress = true; } |
tonyp@1794 | 77 | void clear_in_progress() { _in_progress = false; } |
tonyp@1794 | 78 | bool in_progress() { return _in_progress; } |
tonyp@1794 | 79 | |
tonyp@1794 | 80 | // This flag returns true from the moment a marking cycle is |
tonyp@1794 | 81 | // initiated (during the initial-mark pause when started() is set) |
tonyp@1794 | 82 | // to the moment when the cycle completes (just after the next |
tonyp@1794 | 83 | // marking bitmap has been cleared and in_progress() is |
tonyp@1794 | 84 | // cleared). While this flag is true we will not start another cycle |
tonyp@1794 | 85 | // so that cycles do not overlap. We cannot use just in_progress() |
tonyp@1794 | 86 | // as the CM thread might take some time to wake up before noticing |
tonyp@1794 | 87 | // that started() is set and set in_progress(). |
tonyp@1794 | 88 | bool during_cycle() { return started() || in_progress(); } |
ysr@777 | 89 | |
ysr@777 | 90 | // Yield for GC |
ysr@777 | 91 | void yield(); |
ysr@777 | 92 | |
ysr@777 | 93 | // shutdown |
iveresov@1229 | 94 | void stop(); |
ysr@777 | 95 | }; |