--- a/hotspot/src/share/vm/services/lowMemoryDetector.cpp Wed Feb 02 18:38:40 2011 -0500
+++ b/hotspot/src/share/vm/services/lowMemoryDetector.cpp Wed Feb 02 14:38:01 2011 -0500
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2011, 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
@@ -34,55 +34,11 @@
#include "services/lowMemoryDetector.hpp"
#include "services/management.hpp"
-LowMemoryDetectorThread* LowMemoryDetector::_detector_thread = NULL;
volatile bool LowMemoryDetector::_enabled_for_collected_pools = false;
volatile jint LowMemoryDetector::_disabled_count = 0;
-void LowMemoryDetector::initialize() {
- EXCEPTION_MARK;
-
- instanceKlassHandle klass (THREAD, SystemDictionary::Thread_klass());
- instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
-
- const char thread_name[] = "Low Memory Detector";
- Handle string = java_lang_String::create_from_str(thread_name, CHECK);
-
- // Initialize thread_oop to put it into the system threadGroup
- Handle thread_group (THREAD, Universe::system_thread_group());
- JavaValue result(T_VOID);
- JavaCalls::call_special(&result, thread_oop,
- klass,
- vmSymbols::object_initializer_name(),
- vmSymbols::threadgroup_string_void_signature(),
- thread_group,
- string,
- CHECK);
-
- {
- MutexLocker mu(Threads_lock);
- _detector_thread = new LowMemoryDetectorThread(&low_memory_detector_thread_entry);
-
- // At this point it may be possible that no osthread was created for the
- // JavaThread due to lack of memory. We would have to throw an exception
- // in that case. However, since this must work and we do not allow
- // exceptions anyway, check and abort if this fails.
- if (_detector_thread == NULL || _detector_thread->osthread() == NULL) {
- vm_exit_during_initialization("java.lang.OutOfMemoryError",
- "unable to create new native thread");
- }
-
- java_lang_Thread::set_thread(thread_oop(), _detector_thread);
- java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
- java_lang_Thread::set_daemon(thread_oop());
- _detector_thread->set_threadObj(thread_oop());
-
- Threads::add(_detector_thread);
- Thread::start(_detector_thread);
- }
-}
-
bool LowMemoryDetector::has_pending_requests() {
- assert(LowMemory_lock->owned_by_self(), "Must own LowMemory_lock");
+ 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++) {
@@ -100,47 +56,21 @@
return has_requests;
}
-void LowMemoryDetector::low_memory_detector_thread_entry(JavaThread* jt, TRAPS) {
- while (true) {
- bool sensors_changed = false;
-
- {
- // _no_safepoint_check_flag is used here as LowMemory_lock is a
- // special lock and the VMThread may acquire this lock at safepoint.
- // Need state transition ThreadBlockInVM so that this thread
- // will be handled by safepoint correctly when this thread is
- // notified at a safepoint.
-
- // This ThreadBlockInVM object is not also considered to be
- // suspend-equivalent because LowMemoryDetector threads are
- // not visible to external suspension.
-
- ThreadBlockInVM tbivm(jt);
+void LowMemoryDetector::process_sensor_changes(TRAPS) {
+ ResourceMark rm(THREAD);
+ HandleMark hm(THREAD);
- MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag);
- while (!(sensors_changed = has_pending_requests())) {
- // wait until one of the sensors has pending requests
- LowMemory_lock->wait(Mutex::_no_safepoint_check_flag);
- }
+ // 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);
}
-
- {
- ResourceMark rm(THREAD);
- HandleMark hm(THREAD);
-
- // No need to hold LowMemory_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);
- }
- }
+ if (gc_sensor != NULL && gc_sensor->has_pending_requests()) {
+ gc_sensor->process_pending_requests(CHECK);
}
}
}
@@ -148,7 +78,7 @@
// This method could be called from any Java threads
// and also VMThread.
void LowMemoryDetector::detect_low_memory() {
- MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag);
+ MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
bool has_pending_requests = false;
int num_memory_pools = MemoryService::num_memory_pools();
@@ -166,7 +96,7 @@
}
if (has_pending_requests) {
- LowMemory_lock->notify_all();
+ Service_lock->notify_all();
}
}
@@ -181,14 +111,14 @@
}
{
- MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag);
+ 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
- LowMemory_lock->notify_all();
+ Service_lock->notify_all();
}
}
}
@@ -203,14 +133,14 @@
}
{
- MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag);
+ 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
- LowMemory_lock->notify_all();
+ Service_lock->notify_all();
}
}
}
@@ -384,8 +314,8 @@
}
{
- // Holds LowMemory_lock and update the sensor state
- MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag);
+ // Holds Service_lock and update the sensor state
+ MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
_sensor_on = true;
_sensor_count += count;
_pending_trigger_count = _pending_trigger_count - count;
@@ -410,8 +340,8 @@
}
{
- // Holds LowMemory_lock and update the sensor state
- MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag);
+ // Holds Service_lock and update the sensor state
+ MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
_sensor_on = false;
_pending_clear_count = 0;
_pending_trigger_count = _pending_trigger_count - count;