| /* |
| * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "classfile/systemDictionary.hpp" |
| #include "classfile/vmSymbols.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/interfaceSupport.hpp" |
| #include "runtime/java.hpp" |
| #include "runtime/javaCalls.hpp" |
| #include "runtime/mutex.hpp" |
| #include "runtime/mutexLocker.hpp" |
| #include "services/lowMemoryDetector.hpp" |
| #include "services/management.hpp" |
| |
| volatile bool LowMemoryDetector::_enabled_for_collected_pools = false; |
| volatile jint LowMemoryDetector::_disabled_count = 0; |
| |
| bool LowMemoryDetector::has_pending_requests() { |
| assert(Service_lock->owned_by_self(), "Must own Service_lock"); |
| bool has_requests = false; |
| int num_memory_pools = MemoryService::num_memory_pools(); |
| for (int i = 0; i < num_memory_pools; i++) { |
| MemoryPool* pool = MemoryService::get_memory_pool(i); |
| SensorInfo* sensor = pool->usage_sensor(); |
| if (sensor != NULL) { |
| has_requests = has_requests || sensor->has_pending_requests(); |
| } |
| |
| SensorInfo* gc_sensor = pool->gc_usage_sensor(); |
| if (gc_sensor != NULL) { |
| has_requests = has_requests || gc_sensor->has_pending_requests(); |
| } |
| } |
| return has_requests; |
| } |
| |
| void LowMemoryDetector::process_sensor_changes(TRAPS) { |
| ResourceMark rm(THREAD); |
| HandleMark hm(THREAD); |
| |
| // No need to hold Service_lock to call out to Java |
| int num_memory_pools = MemoryService::num_memory_pools(); |
| for (int i = 0; i < num_memory_pools; i++) { |
| MemoryPool* pool = MemoryService::get_memory_pool(i); |
| SensorInfo* sensor = pool->usage_sensor(); |
| SensorInfo* gc_sensor = pool->gc_usage_sensor(); |
| if (sensor != NULL && sensor->has_pending_requests()) { |
| sensor->process_pending_requests(CHECK); |
| } |
| if (gc_sensor != NULL && gc_sensor->has_pending_requests()) { |
| gc_sensor->process_pending_requests(CHECK); |
| } |
| } |
| } |
| |
| // This method could be called from any Java threads |
| // and also VMThread. |
| void LowMemoryDetector::detect_low_memory() { |
| MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag); |
| |
| bool has_pending_requests = false; |
| int num_memory_pools = MemoryService::num_memory_pools(); |
| for (int i = 0; i < num_memory_pools; i++) { |
| MemoryPool* pool = MemoryService::get_memory_pool(i); |
| SensorInfo* sensor = pool->usage_sensor(); |
| if (sensor != NULL && |
| pool->usage_threshold()->is_high_threshold_supported() && |
| pool->usage_threshold()->high_threshold() != 0) { |
| MemoryUsage usage = pool->get_memory_usage(); |
| sensor->set_gauge_sensor_level(usage, |
| pool->usage_threshold()); |
| has_pending_requests = has_pending_requests || sensor->has_pending_requests(); |
| } |
| } |
| |
| if (has_pending_requests) { |
| Service_lock->notify_all(); |
| } |
| } |
| |
| // This method could be called from any Java threads |
| // and also VMThread. |
| void LowMemoryDetector::detect_low_memory(MemoryPool* pool) { |
| SensorInfo* sensor = pool->usage_sensor(); |
| if (sensor == NULL || |
| !pool->usage_threshold()->is_high_threshold_supported() || |
| pool->usage_threshold()->high_threshold() == 0) { |
| return; |
| } |
| |
| { |
| MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag); |
| |
| MemoryUsage usage = pool->get_memory_usage(); |
| sensor->set_gauge_sensor_level(usage, |
| pool->usage_threshold()); |
| if (sensor->has_pending_requests()) { |
| // notify sensor state update |
| Service_lock->notify_all(); |
| } |
| } |
| } |
| |
| // Only called by VMThread at GC time |
| void LowMemoryDetector::detect_after_gc_memory(MemoryPool* pool) { |
| SensorInfo* sensor = pool->gc_usage_sensor(); |
| if (sensor == NULL || |
| !pool->gc_usage_threshold()->is_high_threshold_supported() || |
| pool->gc_usage_threshold()->high_threshold() == 0) { |
| return; |
| } |
| |
| { |
| MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag); |
| |
| MemoryUsage usage = pool->get_last_collection_usage(); |
| sensor->set_counter_sensor_level(usage, pool->gc_usage_threshold()); |
| |
| if (sensor->has_pending_requests()) { |
| // notify sensor state update |
| Service_lock->notify_all(); |
| } |
| } |
| } |
| |
| // recompute enabled flag |
| void LowMemoryDetector::recompute_enabled_for_collected_pools() { |
| bool enabled = false; |
| int num_memory_pools = MemoryService::num_memory_pools(); |
| for (int i=0; i<num_memory_pools; i++) { |
| MemoryPool* pool = MemoryService::get_memory_pool(i); |
| if (pool->is_collected_pool() && is_enabled(pool)) { |
| enabled = true; |
| break; |
| } |
| } |
| _enabled_for_collected_pools = enabled; |
| } |
| |
| SensorInfo::SensorInfo() { |
| _sensor_obj = NULL; |
| _sensor_on = false; |
| _sensor_count = 0; |
| _pending_trigger_count = 0; |
| _pending_clear_count = 0; |
| } |
| |
| // When this method is used, the memory usage is monitored |
| // as a gauge attribute. Sensor notifications (trigger or |
| // clear) is only emitted at the first time it crosses |
| // a threshold. |
| // |
| // High and low thresholds are designed to provide a |
| // hysteresis mechanism to avoid repeated triggering |
| // of notifications when the attribute value makes small oscillations |
| // around the high or low threshold value. |
| // |
| // The sensor will be triggered if: |
| // (1) the usage is crossing above the high threshold and |
| // the sensor is currently off and no pending |
| // trigger requests; or |
| // (2) the usage is crossing above the high threshold and |
| // the sensor will be off (i.e. sensor is currently on |
| // and has pending clear requests). |
| // |
| // Subsequent crossings of the high threshold value do not cause |
| // any triggers unless the usage becomes less than the low threshold. |
| // |
| // The sensor will be cleared if: |
| // (1) the usage is crossing below the low threshold and |
| // the sensor is currently on and no pending |
| // clear requests; or |
| // (2) the usage is crossing below the low threshold and |
| // the sensor will be on (i.e. sensor is currently off |
| // and has pending trigger requests). |
| // |
| // Subsequent crossings of the low threshold value do not cause |
| // any clears unless the usage becomes greater than or equal |
| // to the high threshold. |
| // |
| // If the current level is between high and low threshold, no change. |
| // |
| void SensorInfo::set_gauge_sensor_level(MemoryUsage usage, ThresholdSupport* high_low_threshold) { |
| assert(Service_lock->owned_by_self(), "Must own Service_lock"); |
| assert(high_low_threshold->is_high_threshold_supported(), "just checking"); |
| |
| bool is_over_high = high_low_threshold->is_high_threshold_crossed(usage); |
| bool is_below_low = high_low_threshold->is_low_threshold_crossed(usage); |
| |
| assert(!(is_over_high && is_below_low), "Can't be both true"); |
| |
| if (is_over_high && |
| ((!_sensor_on && _pending_trigger_count == 0) || |
| _pending_clear_count > 0)) { |
| // low memory detected and need to increment the trigger pending count |
| // if the sensor is off or will be off due to _pending_clear_ > 0 |
| // Request to trigger the sensor |
| _pending_trigger_count++; |
| _usage = usage; |
| |
| if (_pending_clear_count > 0) { |
| // non-zero pending clear requests indicates that there are |
| // pending requests to clear this sensor. |
| // This trigger request needs to clear this clear count |
| // since the resulting sensor flag should be on. |
| _pending_clear_count = 0; |
| } |
| } else if (is_below_low && |
| ((_sensor_on && _pending_clear_count == 0) || |
| (_pending_trigger_count > 0 && _pending_clear_count == 0))) { |
| // memory usage returns below the threshold |
| // Request to clear the sensor if the sensor is on or will be on due to |
| // _pending_trigger_count > 0 and also no clear request |
| _pending_clear_count++; |
| } |
| } |
| |
| // When this method is used, the memory usage is monitored as a |
| // simple counter attribute. The sensor will be triggered |
| // whenever the usage is crossing the threshold to keep track |
| // of the number of times the VM detects such a condition occurs. |
| // |
| // High and low thresholds are designed to provide a |
| // hysteresis mechanism to avoid repeated triggering |
| // of notifications when the attribute value makes small oscillations |
| // around the high or low threshold value. |
| // |
| // The sensor will be triggered if: |
| // - the usage is crossing above the high threshold regardless |
| // of the current sensor state. |
| // |
| // The sensor will be cleared if: |
| // (1) the usage is crossing below the low threshold and |
| // the sensor is currently on; or |
| // (2) the usage is crossing below the low threshold and |
| // the sensor will be on (i.e. sensor is currently off |
| // and has pending trigger requests). |
| void SensorInfo::set_counter_sensor_level(MemoryUsage usage, ThresholdSupport* counter_threshold) { |
| assert(Service_lock->owned_by_self(), "Must own Service_lock"); |
| assert(counter_threshold->is_high_threshold_supported(), "just checking"); |
| |
| bool is_over_high = counter_threshold->is_high_threshold_crossed(usage); |
| bool is_below_low = counter_threshold->is_low_threshold_crossed(usage); |
| |
| assert(!(is_over_high && is_below_low), "Can't be both true"); |
| |
| if (is_over_high) { |
| _pending_trigger_count++; |
| _usage = usage; |
| _pending_clear_count = 0; |
| } else if (is_below_low && (_sensor_on || _pending_trigger_count > 0)) { |
| _pending_clear_count++; |
| } |
| } |
| |
| void SensorInfo::oops_do(OopClosure* f) { |
| f->do_oop((oop*) &_sensor_obj); |
| } |
| |
| void SensorInfo::process_pending_requests(TRAPS) { |
| int pending_count = pending_trigger_count(); |
| if (pending_clear_count() > 0) { |
| clear(pending_count, CHECK); |
| } else { |
| trigger(pending_count, CHECK); |
| } |
| |
| } |
| |
| void SensorInfo::trigger(int count, TRAPS) { |
| assert(count <= _pending_trigger_count, "just checking"); |
| if (_sensor_obj != NULL) { |
| InstanceKlass* sensorKlass = Management::sun_management_Sensor_klass(CHECK); |
| Handle sensor_h(THREAD, _sensor_obj); |
| |
| Symbol* trigger_method_signature; |
| |
| JavaValue result(T_VOID); |
| JavaCallArguments args(sensor_h); |
| args.push_int((int) count); |
| |
| Handle usage_h = MemoryService::create_MemoryUsage_obj(_usage, THREAD); |
| // Call Sensor::trigger(int, MemoryUsage) to send notification to listeners. |
| // When OOME occurs and fails to allocate MemoryUsage object, call |
| // Sensor::trigger(int) instead. The pending request will be processed |
| // but no notification will be sent. |
| if (HAS_PENDING_EXCEPTION) { |
| assert((PENDING_EXCEPTION->is_a(SystemDictionary::OutOfMemoryError_klass())), "we expect only an OOME here"); |
| CLEAR_PENDING_EXCEPTION; |
| trigger_method_signature = vmSymbols::int_void_signature(); |
| } else { |
| trigger_method_signature = vmSymbols::trigger_method_signature(); |
| args.push_oop(usage_h); |
| } |
| |
| JavaCalls::call_virtual(&result, |
| sensorKlass, |
| vmSymbols::trigger_name(), |
| trigger_method_signature, |
| &args, |
| THREAD); |
| |
| if (HAS_PENDING_EXCEPTION) { |
| // We just clear the OOM pending exception that we might have encountered |
| // in Java's tiggerAction(), and continue with updating the counters since |
| // the Java counters have been updated too. |
| assert((PENDING_EXCEPTION->is_a(SystemDictionary::OutOfMemoryError_klass())), "we expect only an OOME here"); |
| CLEAR_PENDING_EXCEPTION; |
| } |
| } |
| |
| { |
| // Holds Service_lock and update the sensor state |
| MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag); |
| assert(_pending_trigger_count > 0, "Must have pending trigger"); |
| _sensor_on = true; |
| _sensor_count += count; |
| _pending_trigger_count = _pending_trigger_count - count; |
| } |
| } |
| |
| void SensorInfo::clear(int count, TRAPS) { |
| { |
| // Holds Service_lock and update the sensor state |
| MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag); |
| if (_pending_clear_count == 0) { |
| // Bail out if we lost a race to set_*_sensor_level() which may have |
| // reactivated the sensor in the meantime because it was triggered again. |
| return; |
| } |
| _sensor_on = false; |
| _sensor_count += count; |
| _pending_clear_count = 0; |
| _pending_trigger_count = _pending_trigger_count - count; |
| } |
| |
| if (_sensor_obj != NULL) { |
| InstanceKlass* sensorKlass = Management::sun_management_Sensor_klass(CHECK); |
| Handle sensor(THREAD, _sensor_obj); |
| |
| JavaValue result(T_VOID); |
| JavaCallArguments args(sensor); |
| args.push_int((int) count); |
| JavaCalls::call_virtual(&result, |
| sensorKlass, |
| vmSymbols::clear_name(), |
| vmSymbols::int_void_signature(), |
| &args, |
| CHECK); |
| } |
| } |
| |
| //-------------------------------------------------------------- |
| // Non-product code |
| |
| #ifndef PRODUCT |
| void SensorInfo::print() { |
| tty->print_cr("%s count = " SIZE_FORMAT " pending_triggers = %d pending_clears = %d", |
| (_sensor_on ? "on" : "off"), |
| _sensor_count, _pending_trigger_count, _pending_clear_count); |
| } |
| |
| #endif // PRODUCT |