author | coleenp |
Sun, 13 Apr 2008 17:43:42 -0400 | |
changeset 360 | 21d113ecbf6a |
parent 1 | 489c9b5090e2 |
child 670 | ddf3e9583f2f |
permissions | -rw-r--r-- |
1 | 1 |
/* |
2 |
* Copyright 2002-2006 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 |
*/ |
|
24 |
||
25 |
package sun.jvm.hotspot.utilities; |
|
26 |
||
27 |
import java.io.*; |
|
28 |
import java.util.*; |
|
29 |
import sun.jvm.hotspot.debugger.*; |
|
30 |
import sun.jvm.hotspot.gc_interface.*; |
|
31 |
import sun.jvm.hotspot.memory.*; |
|
32 |
import sun.jvm.hotspot.oops.*; |
|
33 |
import sun.jvm.hotspot.runtime.*; |
|
34 |
import sun.jvm.hotspot.utilities.*; |
|
35 |
||
36 |
/** For a set of known roots, descends recursively into the object |
|
37 |
graph, for each object recording those objects (and their fields) |
|
38 |
which point to it. NOTE: currently only a subset of the roots |
|
39 |
known to the VM is exposed to the SA: objects on the stack, static |
|
40 |
fields in classes, and JNI handles. These should be most of the |
|
41 |
user-level roots keeping objects alive. */ |
|
42 |
||
43 |
public class ReversePtrsAnalysis { |
|
44 |
// Used for debugging this code |
|
45 |
private static final boolean DEBUG = false; |
|
46 |
||
47 |
public ReversePtrsAnalysis() { |
|
48 |
} |
|
49 |
||
50 |
/** Sets an optional progress thunk */ |
|
51 |
public void setHeapProgressThunk(HeapProgressThunk thunk) { |
|
52 |
progressThunk = thunk; |
|
53 |
} |
|
54 |
||
55 |
||
56 |
/** Runs the analysis algorithm */ |
|
57 |
public void run() { |
|
58 |
if (VM.getVM().getRevPtrs() != null) { |
|
59 |
return; // Assume already done |
|
60 |
} |
|
61 |
||
62 |
VM vm = VM.getVM(); |
|
63 |
rp = new ReversePtrs(); |
|
64 |
vm.setRevPtrs(rp); |
|
65 |
Universe universe = vm.getUniverse(); |
|
66 |
CollectedHeap collHeap = universe.heap(); |
|
67 |
usedSize = collHeap.used(); |
|
68 |
visitedSize = 0; |
|
69 |
||
70 |
// Note that an experiment to iterate the heap linearly rather |
|
71 |
// than in recursive-descent order has been done. It turns out |
|
72 |
// that the recursive-descent algorithm is nearly twice as fast |
|
73 |
// due to the fact that it scans only live objects and (currently) |
|
74 |
// only a fraction of the perm gen, namely the static fields |
|
75 |
// contained in instanceKlasses. (Iterating the heap linearly |
|
76 |
// would also change the semantics of the result so that |
|
77 |
// ReversePtrs.get() would return a non-null value even for dead |
|
78 |
// objects.) Nonetheless, the reverse pointer computation is still |
|
79 |
// quite slow and optimization in field iteration of objects |
|
80 |
// should be done. |
|
81 |
||
82 |
if (progressThunk != null) { |
|
83 |
// Get it started |
|
84 |
progressThunk.heapIterationFractionUpdate(0); |
|
85 |
} |
|
86 |
||
87 |
// Allocate mark bits for heap |
|
88 |
markBits = new MarkBits(collHeap); |
|
89 |
||
90 |
// Get a hold of the object heap |
|
91 |
heap = vm.getObjectHeap(); |
|
92 |
||
93 |
// Do each thread's roots |
|
94 |
for (JavaThread thread = VM.getVM().getThreads().first(); |
|
95 |
thread != null; |
|
96 |
thread = thread.next()) { |
|
97 |
ByteArrayOutputStream bos = new ByteArrayOutputStream(); |
|
98 |
thread.printThreadIDOn(new PrintStream(bos)); |
|
99 |
String threadDesc = |
|
100 |
" in thread \"" + thread.getThreadName() + |
|
101 |
"\" (id " + bos.toString() + ")"; |
|
102 |
doStack(thread, |
|
103 |
new RootVisitor("Stack root" + threadDesc)); |
|
104 |
doJNIHandleBlock(thread.activeHandles(), |
|
105 |
new RootVisitor("JNI handle root" + threadDesc)); |
|
106 |
} |
|
107 |
||
108 |
// Do global JNI handles |
|
109 |
JNIHandles handles = VM.getVM().getJNIHandles(); |
|
110 |
doJNIHandleBlock(handles.globalHandles(), |
|
111 |
new RootVisitor("Global JNI handle root")); |
|
112 |
doJNIHandleBlock(handles.weakGlobalHandles(), |
|
113 |
new RootVisitor("Weak global JNI handle root")); |
|
114 |
||
115 |
// Do Java-level static fields in perm gen |
|
116 |
heap.iteratePerm(new DefaultHeapVisitor() { |
|
117 |
public boolean doObj(Oop obj) { |
|
118 |
if (obj instanceof InstanceKlass) { |
|
119 |
final InstanceKlass ik = (InstanceKlass) obj; |
|
120 |
ik.iterateFields( |
|
121 |
new DefaultOopVisitor() { |
|
122 |
public void doOop(OopField field, boolean isVMField) { |
|
123 |
Oop next = field.getValue(ik); |
|
124 |
LivenessPathElement lp = new LivenessPathElement(null, |
|
125 |
new NamedFieldIdentifier("Static field \"" + |
|
126 |
field.getID().getName() + |
|
127 |
"\" in class \"" + |
|
128 |
ik.getName().asString() + "\"")); |
|
129 |
rp.put(lp, next); |
|
130 |
try { |
|
131 |
markAndTraverse(next); |
|
132 |
} catch (AddressException e) { |
|
133 |
System.err.print("RevPtrs analysis: WARNING: AddressException at 0x" + |
|
134 |
Long.toHexString(e.getAddress()) + |
|
135 |
" while traversing static fields of InstanceKlass "); |
|
136 |
ik.printValueOn(System.err); |
|
137 |
System.err.println(); |
|
138 |
} catch (UnknownOopException e) { |
|
139 |
System.err.println("RevPtrs analysis: WARNING: UnknownOopException while " + |
|
140 |
"traversing static fields of InstanceKlass "); |
|
141 |
ik.printValueOn(System.err); |
|
142 |
System.err.println(); |
|
143 |
} |
|
144 |
} |
|
145 |
}, |
|
146 |
false); |
|
147 |
} |
|
148 |
return false; |
|
149 |
} |
|
150 |
}); |
|
151 |
||
152 |
if (progressThunk != null) { |
|
153 |
progressThunk.heapIterationComplete(); |
|
154 |
} |
|
155 |
||
156 |
// Clear out markBits |
|
157 |
markBits = null; |
|
158 |
} |
|
159 |
||
160 |
||
161 |
//--------------------------------------------------------------------------- |
|
162 |
// Internals only below this point |
|
163 |
// |
|
164 |
private HeapProgressThunk progressThunk; |
|
165 |
private long usedSize; |
|
166 |
private long visitedSize; |
|
167 |
private double lastNotificationFraction; |
|
168 |
private static final double MINIMUM_NOTIFICATION_FRACTION = 0.01; |
|
169 |
private ObjectHeap heap; |
|
170 |
private MarkBits markBits; |
|
171 |
private int depth; // Debugging only |
|
172 |
private ReversePtrs rp; |
|
173 |
||
174 |
private void markAndTraverse(OopHandle handle) { |
|
175 |
try { |
|
176 |
markAndTraverse(heap.newOop(handle)); |
|
177 |
} catch (AddressException e) { |
|
178 |
System.err.println("RevPtrs analysis: WARNING: AddressException at 0x" + |
|
179 |
Long.toHexString(e.getAddress()) + |
|
180 |
" while traversing oop at " + handle); |
|
181 |
} catch (UnknownOopException e) { |
|
182 |
System.err.println("RevPtrs analysis: WARNING: UnknownOopException for " + |
|
183 |
"oop at " + handle); |
|
184 |
} |
|
185 |
} |
|
186 |
||
187 |
private void printHeader() { |
|
188 |
for (int i = 0; i < depth; i++) { |
|
189 |
System.err.print(" "); |
|
190 |
} |
|
191 |
} |
|
192 |
||
193 |
private void markAndTraverse(final Oop obj) { |
|
194 |
||
195 |
// End of path |
|
196 |
if (obj == null) { |
|
197 |
return; |
|
198 |
} |
|
199 |
||
200 |
// Visited object |
|
201 |
if (!markBits.mark(obj)) { |
|
202 |
return; |
|
203 |
} |
|
204 |
||
205 |
// Root of work list for objects to be visited. A simple |
|
206 |
// stack for saving new objects to be analyzed. |
|
207 |
||
208 |
final Stack workList = new Stack(); |
|
209 |
||
210 |
// Next object to be visited. |
|
211 |
Oop next = obj; |
|
212 |
||
213 |
try { |
|
214 |
// Node in the list currently being visited. |
|
215 |
||
216 |
while (true) { |
|
217 |
final Oop currObj = next; |
|
218 |
||
219 |
// For the progress meter |
|
220 |
if (progressThunk != null) { |
|
221 |
visitedSize += currObj.getObjectSize(); |
|
222 |
double curFrac = (double) visitedSize / (double) usedSize; |
|
223 |
if (curFrac > |
|
224 |
lastNotificationFraction + MINIMUM_NOTIFICATION_FRACTION) { |
|
225 |
progressThunk.heapIterationFractionUpdate(curFrac); |
|
226 |
lastNotificationFraction = curFrac; |
|
227 |
} |
|
228 |
} |
|
229 |
||
230 |
if (DEBUG) { |
|
231 |
++depth; |
|
232 |
printHeader(); |
|
233 |
System.err.println("ReversePtrs.markAndTraverse(" + |
|
234 |
currObj.getHandle() + ")"); |
|
235 |
} |
|
236 |
||
237 |
// Iterate over the references in the object. Do the |
|
238 |
// reverse pointer analysis for each reference. |
|
239 |
// Add the reference to the work-list so that its |
|
240 |
// references will be visited. |
|
241 |
currObj.iterate(new DefaultOopVisitor() { |
|
242 |
public void doOop(OopField field, boolean isVMField) { |
|
243 |
// "field" refers to a reference in currObj |
|
244 |
Oop next = field.getValue(currObj); |
|
245 |
rp.put(new LivenessPathElement(currObj, field.getID()), next); |
|
246 |
if ((next != null) && markBits.mark(next)) { |
|
247 |
workList.push(next); |
|
248 |
} |
|
249 |
} |
|
250 |
}, false); |
|
251 |
||
252 |
if (DEBUG) { |
|
253 |
--depth; |
|
254 |
} |
|
255 |
||
256 |
// Get the next object to visit. |
|
257 |
next = (Oop) workList.pop(); |
|
258 |
} |
|
259 |
} catch (EmptyStackException e) { |
|
260 |
// Done |
|
261 |
} catch (NullPointerException e) { |
|
262 |
System.err.println("ReversePtrs: WARNING: " + e + |
|
263 |
" during traversal"); |
|
264 |
} catch (Exception e) { |
|
265 |
System.err.println("ReversePtrs: WARNING: " + e + |
|
266 |
" during traversal"); |
|
267 |
} |
|
268 |
} |
|
269 |
||
270 |
||
271 |
class RootVisitor implements AddressVisitor { |
|
272 |
RootVisitor(String baseRootDescription) { |
|
273 |
this.baseRootDescription = baseRootDescription; |
|
274 |
} |
|
275 |
||
276 |
public void visitAddress(Address addr) { |
|
277 |
Oop next = heap.newOop(addr.getOopHandleAt(0)); |
|
278 |
LivenessPathElement lp = new LivenessPathElement(null, |
|
279 |
new NamedFieldIdentifier(baseRootDescription + |
|
280 |
" @ " + addr)); |
|
281 |
rp.put(lp, next); |
|
282 |
markAndTraverse(next); |
|
283 |
} |
|
284 |
||
360
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
285 |
public void visitCompOopAddress(Address addr) { |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
286 |
Oop next = heap.newOop(addr.getCompOopHandleAt(0)); |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
287 |
LivenessPathElement lp = new LivenessPathElement(null, |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
288 |
new NamedFieldIdentifier(baseRootDescription + |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
289 |
" @ " + addr)); |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
290 |
rp.put(lp, next); |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
291 |
markAndTraverse(next); |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
292 |
} |
21d113ecbf6a
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
coleenp
parents:
1
diff
changeset
|
293 |
|
1 | 294 |
private String baseRootDescription; |
295 |
} |
|
296 |
||
297 |
// Traverse the roots on a given thread's stack |
|
298 |
private void doStack(JavaThread thread, AddressVisitor oopVisitor) { |
|
299 |
for (StackFrameStream fst = new StackFrameStream(thread); !fst.isDone(); fst.next()) { |
|
300 |
fst.getCurrent().oopsDo(oopVisitor, fst.getRegisterMap()); |
|
301 |
} |
|
302 |
} |
|
303 |
||
304 |
// Traverse a JNIHandleBlock |
|
305 |
private void doJNIHandleBlock(JNIHandleBlock handles, AddressVisitor oopVisitor) { |
|
306 |
handles.oopsDo(oopVisitor); |
|
307 |
} |
|
308 |
} |