Mercurial > hg > graal-compiler
annotate src/share/vm/services/lowMemoryDetector.cpp @ 1763:d6f45b55c972
4809552: Optimize Arrays.fill(...)
Reviewed-by: kvn
author | never |
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date | Fri, 27 Aug 2010 17:33:49 -0700 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 2003, 2007, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_lowMemoryDetector.cpp.incl" | |
27 | |
28 LowMemoryDetectorThread* LowMemoryDetector::_detector_thread = NULL; | |
29 volatile bool LowMemoryDetector::_enabled_for_collected_pools = false; | |
30 volatile jint LowMemoryDetector::_disabled_count = 0; | |
31 | |
32 void LowMemoryDetector::initialize() { | |
33 EXCEPTION_MARK; | |
34 | |
1142 | 35 instanceKlassHandle klass (THREAD, SystemDictionary::Thread_klass()); |
0 | 36 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK); |
37 | |
38 const char thread_name[] = "Low Memory Detector"; | |
39 Handle string = java_lang_String::create_from_str(thread_name, CHECK); | |
40 | |
41 // Initialize thread_oop to put it into the system threadGroup | |
42 Handle thread_group (THREAD, Universe::system_thread_group()); | |
43 JavaValue result(T_VOID); | |
44 JavaCalls::call_special(&result, thread_oop, | |
45 klass, | |
46 vmSymbolHandles::object_initializer_name(), | |
47 vmSymbolHandles::threadgroup_string_void_signature(), | |
48 thread_group, | |
49 string, | |
50 CHECK); | |
51 | |
52 { | |
53 MutexLocker mu(Threads_lock); | |
54 _detector_thread = new LowMemoryDetectorThread(&low_memory_detector_thread_entry); | |
55 | |
56 // At this point it may be possible that no osthread was created for the | |
57 // JavaThread due to lack of memory. We would have to throw an exception | |
58 // in that case. However, since this must work and we do not allow | |
59 // exceptions anyway, check and abort if this fails. | |
60 if (_detector_thread == NULL || _detector_thread->osthread() == NULL) { | |
61 vm_exit_during_initialization("java.lang.OutOfMemoryError", | |
62 "unable to create new native thread"); | |
63 } | |
64 | |
65 java_lang_Thread::set_thread(thread_oop(), _detector_thread); | |
66 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority); | |
67 java_lang_Thread::set_daemon(thread_oop()); | |
68 _detector_thread->set_threadObj(thread_oop()); | |
69 | |
70 Threads::add(_detector_thread); | |
71 Thread::start(_detector_thread); | |
72 } | |
73 } | |
74 | |
75 bool LowMemoryDetector::has_pending_requests() { | |
76 assert(LowMemory_lock->owned_by_self(), "Must own LowMemory_lock"); | |
77 bool has_requests = false; | |
78 int num_memory_pools = MemoryService::num_memory_pools(); | |
79 for (int i = 0; i < num_memory_pools; i++) { | |
80 MemoryPool* pool = MemoryService::get_memory_pool(i); | |
81 SensorInfo* sensor = pool->usage_sensor(); | |
82 if (sensor != NULL) { | |
83 has_requests = has_requests || sensor->has_pending_requests(); | |
84 } | |
85 | |
86 SensorInfo* gc_sensor = pool->gc_usage_sensor(); | |
87 if (gc_sensor != NULL) { | |
88 has_requests = has_requests || gc_sensor->has_pending_requests(); | |
89 } | |
90 } | |
91 return has_requests; | |
92 } | |
93 | |
94 void LowMemoryDetector::low_memory_detector_thread_entry(JavaThread* jt, TRAPS) { | |
95 while (true) { | |
96 bool sensors_changed = false; | |
97 | |
98 { | |
99 // _no_safepoint_check_flag is used here as LowMemory_lock is a | |
100 // special lock and the VMThread may acquire this lock at safepoint. | |
101 // Need state transition ThreadBlockInVM so that this thread | |
102 // will be handled by safepoint correctly when this thread is | |
103 // notified at a safepoint. | |
104 | |
105 // This ThreadBlockInVM object is not also considered to be | |
106 // suspend-equivalent because LowMemoryDetector threads are | |
107 // not visible to external suspension. | |
108 | |
109 ThreadBlockInVM tbivm(jt); | |
110 | |
111 MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag); | |
112 while (!(sensors_changed = has_pending_requests())) { | |
113 // wait until one of the sensors has pending requests | |
114 LowMemory_lock->wait(Mutex::_no_safepoint_check_flag); | |
115 } | |
116 } | |
117 | |
118 { | |
119 ResourceMark rm(THREAD); | |
120 HandleMark hm(THREAD); | |
121 | |
122 // No need to hold LowMemory_lock to call out to Java | |
123 int num_memory_pools = MemoryService::num_memory_pools(); | |
124 for (int i = 0; i < num_memory_pools; i++) { | |
125 MemoryPool* pool = MemoryService::get_memory_pool(i); | |
126 SensorInfo* sensor = pool->usage_sensor(); | |
127 SensorInfo* gc_sensor = pool->gc_usage_sensor(); | |
128 if (sensor != NULL && sensor->has_pending_requests()) { | |
129 sensor->process_pending_requests(CHECK); | |
130 } | |
131 if (gc_sensor != NULL && gc_sensor->has_pending_requests()) { | |
132 gc_sensor->process_pending_requests(CHECK); | |
133 } | |
134 } | |
135 } | |
136 } | |
137 } | |
138 | |
139 // This method could be called from any Java threads | |
140 // and also VMThread. | |
141 void LowMemoryDetector::detect_low_memory() { | |
142 MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag); | |
143 | |
144 bool has_pending_requests = false; | |
145 int num_memory_pools = MemoryService::num_memory_pools(); | |
146 for (int i = 0; i < num_memory_pools; i++) { | |
147 MemoryPool* pool = MemoryService::get_memory_pool(i); | |
148 SensorInfo* sensor = pool->usage_sensor(); | |
149 if (sensor != NULL && | |
150 pool->usage_threshold()->is_high_threshold_supported() && | |
151 pool->usage_threshold()->high_threshold() != 0) { | |
152 MemoryUsage usage = pool->get_memory_usage(); | |
153 sensor->set_gauge_sensor_level(usage, | |
154 pool->usage_threshold()); | |
155 has_pending_requests = has_pending_requests || sensor->has_pending_requests(); | |
156 } | |
157 } | |
158 | |
159 if (has_pending_requests) { | |
160 LowMemory_lock->notify_all(); | |
161 } | |
162 } | |
163 | |
164 // This method could be called from any Java threads | |
165 // and also VMThread. | |
166 void LowMemoryDetector::detect_low_memory(MemoryPool* pool) { | |
167 SensorInfo* sensor = pool->usage_sensor(); | |
168 if (sensor == NULL || | |
169 !pool->usage_threshold()->is_high_threshold_supported() || | |
170 pool->usage_threshold()->high_threshold() == 0) { | |
171 return; | |
172 } | |
173 | |
174 { | |
175 MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag); | |
176 | |
177 MemoryUsage usage = pool->get_memory_usage(); | |
178 sensor->set_gauge_sensor_level(usage, | |
179 pool->usage_threshold()); | |
180 if (sensor->has_pending_requests()) { | |
181 // notify sensor state update | |
182 LowMemory_lock->notify_all(); | |
183 } | |
184 } | |
185 } | |
186 | |
187 // Only called by VMThread at GC time | |
188 void LowMemoryDetector::detect_after_gc_memory(MemoryPool* pool) { | |
189 SensorInfo* sensor = pool->gc_usage_sensor(); | |
190 if (sensor == NULL || | |
191 !pool->gc_usage_threshold()->is_high_threshold_supported() || | |
192 pool->gc_usage_threshold()->high_threshold() == 0) { | |
193 return; | |
194 } | |
195 | |
196 { | |
197 MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag); | |
198 | |
199 MemoryUsage usage = pool->get_last_collection_usage(); | |
200 sensor->set_counter_sensor_level(usage, pool->gc_usage_threshold()); | |
201 | |
202 if (sensor->has_pending_requests()) { | |
203 // notify sensor state update | |
204 LowMemory_lock->notify_all(); | |
205 } | |
206 } | |
207 } | |
208 | |
209 // recompute enabled flag | |
210 void LowMemoryDetector::recompute_enabled_for_collected_pools() { | |
211 bool enabled = false; | |
212 int num_memory_pools = MemoryService::num_memory_pools(); | |
213 for (int i=0; i<num_memory_pools; i++) { | |
214 MemoryPool* pool = MemoryService::get_memory_pool(i); | |
215 if (pool->is_collected_pool() && is_enabled(pool)) { | |
216 enabled = true; | |
217 break; | |
218 } | |
219 } | |
220 _enabled_for_collected_pools = enabled; | |
221 } | |
222 | |
223 SensorInfo::SensorInfo() { | |
224 _sensor_obj = NULL; | |
225 _sensor_on = false; | |
226 _sensor_count = 0; | |
227 _pending_trigger_count = 0; | |
228 _pending_clear_count = 0; | |
229 } | |
230 | |
231 // When this method is used, the memory usage is monitored | |
232 // as a gauge attribute. Sensor notifications (trigger or | |
233 // clear) is only emitted at the first time it crosses | |
234 // a threshold. | |
235 // | |
236 // High and low thresholds are designed to provide a | |
237 // hysteresis mechanism to avoid repeated triggering | |
238 // of notifications when the attribute value makes small oscillations | |
239 // around the high or low threshold value. | |
240 // | |
241 // The sensor will be triggered if: | |
242 // (1) the usage is crossing above the high threshold and | |
243 // the sensor is currently off and no pending | |
244 // trigger requests; or | |
245 // (2) the usage is crossing above the high threshold and | |
246 // the sensor will be off (i.e. sensor is currently on | |
247 // and has pending clear requests). | |
248 // | |
249 // Subsequent crossings of the high threshold value do not cause | |
250 // any triggers unless the usage becomes less than the low threshold. | |
251 // | |
252 // The sensor will be cleared if: | |
253 // (1) the usage is crossing below the low threshold and | |
254 // the sensor is currently on and no pending | |
255 // clear requests; or | |
256 // (2) the usage is crossing below the low threshold and | |
257 // the sensor will be on (i.e. sensor is currently off | |
258 // and has pending trigger requests). | |
259 // | |
260 // Subsequent crossings of the low threshold value do not cause | |
261 // any clears unless the usage becomes greater than or equal | |
262 // to the high threshold. | |
263 // | |
264 // If the current level is between high and low threhsold, no change. | |
265 // | |
266 void SensorInfo::set_gauge_sensor_level(MemoryUsage usage, ThresholdSupport* high_low_threshold) { | |
267 assert(high_low_threshold->is_high_threshold_supported(), "just checking"); | |
268 | |
269 bool is_over_high = high_low_threshold->is_high_threshold_crossed(usage); | |
270 bool is_below_low = high_low_threshold->is_low_threshold_crossed(usage); | |
271 | |
272 assert(!(is_over_high && is_below_low), "Can't be both true"); | |
273 | |
274 if (is_over_high && | |
275 ((!_sensor_on && _pending_trigger_count == 0) || | |
276 _pending_clear_count > 0)) { | |
277 // low memory detected and need to increment the trigger pending count | |
278 // if the sensor is off or will be off due to _pending_clear_ > 0 | |
279 // Request to trigger the sensor | |
280 _pending_trigger_count++; | |
281 _usage = usage; | |
282 | |
283 if (_pending_clear_count > 0) { | |
284 // non-zero pending clear requests indicates that there are | |
285 // pending requests to clear this sensor. | |
286 // This trigger request needs to clear this clear count | |
287 // since the resulting sensor flag should be on. | |
288 _pending_clear_count = 0; | |
289 } | |
290 } else if (is_below_low && | |
291 ((_sensor_on && _pending_clear_count == 0) || | |
292 (_pending_trigger_count > 0 && _pending_clear_count == 0))) { | |
293 // memory usage returns below the threshold | |
294 // Request to clear the sensor if the sensor is on or will be on due to | |
295 // _pending_trigger_count > 0 and also no clear request | |
296 _pending_clear_count++; | |
297 } | |
298 } | |
299 | |
300 // When this method is used, the memory usage is monitored as a | |
301 // simple counter attribute. The sensor will be triggered | |
302 // whenever the usage is crossing the threshold to keep track | |
303 // of the number of times the VM detects such a condition occurs. | |
304 // | |
305 // High and low thresholds are designed to provide a | |
306 // hysteresis mechanism to avoid repeated triggering | |
307 // of notifications when the attribute value makes small oscillations | |
308 // around the high or low threshold value. | |
309 // | |
310 // The sensor will be triggered if: | |
311 // - the usage is crossing above the high threshold regardless | |
312 // of the current sensor state. | |
313 // | |
314 // The sensor will be cleared if: | |
315 // (1) the usage is crossing below the low threshold and | |
316 // the sensor is currently on; or | |
317 // (2) the usage is crossing below the low threshold and | |
318 // the sensor will be on (i.e. sensor is currently off | |
319 // and has pending trigger requests). | |
320 void SensorInfo::set_counter_sensor_level(MemoryUsage usage, ThresholdSupport* counter_threshold) { | |
321 assert(counter_threshold->is_high_threshold_supported(), "just checking"); | |
322 | |
323 bool is_over_high = counter_threshold->is_high_threshold_crossed(usage); | |
324 bool is_below_low = counter_threshold->is_low_threshold_crossed(usage); | |
325 | |
326 assert(!(is_over_high && is_below_low), "Can't be both true"); | |
327 | |
328 if (is_over_high) { | |
329 _pending_trigger_count++; | |
330 _usage = usage; | |
331 _pending_clear_count = 0; | |
332 } else if (is_below_low && (_sensor_on || _pending_trigger_count > 0)) { | |
333 _pending_clear_count++; | |
334 } | |
335 } | |
336 | |
337 void SensorInfo::oops_do(OopClosure* f) { | |
338 f->do_oop((oop*) &_sensor_obj); | |
339 } | |
340 | |
341 void SensorInfo::process_pending_requests(TRAPS) { | |
342 if (!has_pending_requests()) { | |
343 return; | |
344 } | |
345 | |
346 int pending_count = pending_trigger_count(); | |
347 if (pending_clear_count() > 0) { | |
348 clear(pending_count, CHECK); | |
349 } else { | |
350 trigger(pending_count, CHECK); | |
351 } | |
352 | |
353 } | |
354 | |
355 void SensorInfo::trigger(int count, TRAPS) { | |
356 assert(count <= _pending_trigger_count, "just checking"); | |
357 | |
358 if (_sensor_obj != NULL) { | |
359 klassOop k = Management::sun_management_Sensor_klass(CHECK); | |
360 instanceKlassHandle sensorKlass (THREAD, k); | |
361 Handle sensor_h(THREAD, _sensor_obj); | |
362 Handle usage_h = MemoryService::create_MemoryUsage_obj(_usage, CHECK); | |
363 | |
364 JavaValue result(T_VOID); | |
365 JavaCallArguments args(sensor_h); | |
366 args.push_int((int) count); | |
367 args.push_oop(usage_h); | |
368 | |
369 JavaCalls::call_virtual(&result, | |
370 sensorKlass, | |
371 vmSymbolHandles::trigger_name(), | |
372 vmSymbolHandles::trigger_method_signature(), | |
373 &args, | |
374 CHECK); | |
375 } | |
376 | |
377 { | |
378 // Holds LowMemory_lock and update the sensor state | |
379 MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag); | |
380 _sensor_on = true; | |
381 _sensor_count += count; | |
382 _pending_trigger_count = _pending_trigger_count - count; | |
383 } | |
384 } | |
385 | |
386 void SensorInfo::clear(int count, TRAPS) { | |
387 if (_sensor_obj != NULL) { | |
388 klassOop k = Management::sun_management_Sensor_klass(CHECK); | |
389 instanceKlassHandle sensorKlass (THREAD, k); | |
390 Handle sensor(THREAD, _sensor_obj); | |
391 | |
392 JavaValue result(T_VOID); | |
393 JavaCallArguments args(sensor); | |
394 args.push_int((int) count); | |
395 JavaCalls::call_virtual(&result, | |
396 sensorKlass, | |
397 vmSymbolHandles::clear_name(), | |
398 vmSymbolHandles::int_void_signature(), | |
399 &args, | |
400 CHECK); | |
401 } | |
402 | |
403 { | |
404 // Holds LowMemory_lock and update the sensor state | |
405 MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag); | |
406 _sensor_on = false; | |
407 _pending_clear_count = 0; | |
408 _pending_trigger_count = _pending_trigger_count - count; | |
409 } | |
410 } | |
411 | |
412 //-------------------------------------------------------------- | |
413 // Non-product code | |
414 | |
415 #ifndef PRODUCT | |
416 void SensorInfo::print() { | |
417 tty->print_cr("%s count = %ld pending_triggers = %ld pending_clears = %ld", | |
418 (_sensor_on ? "on" : "off"), | |
419 _sensor_count, _pending_trigger_count, _pending_clear_count); | |
420 } | |
421 | |
422 #endif // PRODUCT |