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src/share/vm/gc_implementation/g1/bufferingOopClosure.hpp@0bfd3fb24150
src/share/vm/gc_implementation/g1/bufferingOopClosure.hpp
Tue, 13 Apr 2010 13:52:10 -0700
- author
- jmasa
- date
- Tue, 13 Apr 2010 13:52:10 -0700
- changeset 1822
- 0bfd3fb24150
- parent 1280
- df6caf649ff7
- child 1907
- c18cbe5936b8
- permissions
- -rw-r--r--
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
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 // A BufferingOops closure tries to separate out the cost of finding roots
26 // from the cost of applying closures to them. It maintains an array of
27 // ref-containing locations. Until the array is full, applying the closure
28 // to an oop* merely records that location in the array. Since this
29 // closure app cost is small, an elapsed timer can approximately attribute
30 // all of this cost to the cost of finding the roots. When the array fills
31 // up, the wrapped closure is applied to all elements, keeping track of
32 // this elapsed time of this process, and leaving the array empty.
33 // The caller must be sure to call "done" to process any unprocessed
34 // buffered entriess.
36 class Generation;
37 class HeapRegion;
39 class BufferingOopClosure: public OopClosure {
40 protected:
41 enum PrivateConstants {
42 BufferLength = 1024
43 };
45 StarTask _buffer[BufferLength];
46 StarTask* _buffer_top;
47 StarTask* _buffer_curr;
49 OopClosure* _oc;
50 double _closure_app_seconds;
52 void process_buffer () {
53 double start = os::elapsedTime();
54 for (StarTask* curr = _buffer; curr < _buffer_curr; ++curr) {
55 if (curr->is_narrow()) {
56 assert(UseCompressedOops, "Error");
57 _oc->do_oop((narrowOop*)(*curr));
58 } else {
59 _oc->do_oop((oop*)(*curr));
60 }
61 }
62 _buffer_curr = _buffer;
63 _closure_app_seconds += (os::elapsedTime() - start);
64 }
66 template <class T> inline void do_oop_work(T* p) {
67 if (_buffer_curr == _buffer_top) {
68 process_buffer();
69 }
70 StarTask new_ref(p);
71 *_buffer_curr = new_ref;
72 ++_buffer_curr;
73 }
75 public:
76 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
77 virtual void do_oop(oop* p) { do_oop_work(p); }
79 void done () {
80 if (_buffer_curr > _buffer) {
81 process_buffer();
82 }
83 }
84 double closure_app_seconds () {
85 return _closure_app_seconds;
86 }
87 BufferingOopClosure (OopClosure *oc) :
88 _oc(oc),
89 _buffer_curr(_buffer), _buffer_top(_buffer + BufferLength),
90 _closure_app_seconds(0.0) { }
91 };
93 class BufferingOopsInGenClosure: public OopsInGenClosure {
94 BufferingOopClosure _boc;
95 OopsInGenClosure* _oc;
96 protected:
97 template <class T> inline void do_oop_work(T* p) {
98 assert(generation()->is_in_reserved((void*)p), "Must be in!");
99 _boc.do_oop(p);
100 }
101 public:
102 BufferingOopsInGenClosure(OopsInGenClosure *oc) :
103 _boc(oc), _oc(oc) {}
105 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
106 virtual void do_oop(oop* p) { do_oop_work(p); }
108 void done() {
109 _boc.done();
110 }
112 double closure_app_seconds () {
113 return _boc.closure_app_seconds();
114 }
116 void set_generation(Generation* gen) {
117 OopsInGenClosure::set_generation(gen);
118 _oc->set_generation(gen);
119 }
121 void reset_generation() {
122 // Make sure we finish the current work with the current generation.
123 _boc.done();
124 OopsInGenClosure::reset_generation();
125 _oc->reset_generation();
126 }
128 };
131 class BufferingOopsInHeapRegionClosure: public OopsInHeapRegionClosure {
132 private:
133 enum PrivateConstants {
134 BufferLength = 1024
135 };
137 StarTask _buffer[BufferLength];
138 StarTask* _buffer_top;
139 StarTask* _buffer_curr;
141 HeapRegion* _hr_buffer[BufferLength];
142 HeapRegion** _hr_curr;
144 OopsInHeapRegionClosure* _oc;
145 double _closure_app_seconds;
147 void process_buffer () {
149 assert((_hr_curr - _hr_buffer) == (_buffer_curr - _buffer),
150 "the two lengths should be the same");
152 double start = os::elapsedTime();
153 HeapRegion** hr_curr = _hr_buffer;
154 HeapRegion* hr_prev = NULL;
155 for (StarTask* curr = _buffer; curr < _buffer_curr; ++curr) {
156 HeapRegion* region = *hr_curr;
157 if (region != hr_prev) {
158 _oc->set_region(region);
159 hr_prev = region;
160 }
161 if (curr->is_narrow()) {
162 assert(UseCompressedOops, "Error");
163 _oc->do_oop((narrowOop*)(*curr));
164 } else {
165 _oc->do_oop((oop*)(*curr));
166 }
167 ++hr_curr;
168 }
169 _buffer_curr = _buffer;
170 _hr_curr = _hr_buffer;
171 _closure_app_seconds += (os::elapsedTime() - start);
172 }
174 public:
175 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
176 virtual void do_oop( oop* p) { do_oop_work(p); }
178 template <class T> void do_oop_work(T* p) {
179 if (_buffer_curr == _buffer_top) {
180 assert(_hr_curr > _hr_buffer, "_hr_curr should be consistent with _buffer_curr");
181 process_buffer();
182 }
183 StarTask new_ref(p);
184 *_buffer_curr = new_ref;
185 ++_buffer_curr;
186 *_hr_curr = _from;
187 ++_hr_curr;
188 }
189 void done () {
190 if (_buffer_curr > _buffer) {
191 assert(_hr_curr > _hr_buffer, "_hr_curr should be consistent with _buffer_curr");
192 process_buffer();
193 }
194 }
195 double closure_app_seconds () {
196 return _closure_app_seconds;
197 }
198 BufferingOopsInHeapRegionClosure (OopsInHeapRegionClosure *oc) :
199 _oc(oc),
200 _buffer_curr(_buffer), _buffer_top(_buffer + BufferLength),
201 _hr_curr(_hr_buffer),
202 _closure_app_seconds(0.0) { }
203 };
