src/share/vm/services/lowMemoryDetector.cpp

rev 2029 : 6766644: Redefinition of compiled method fails with assertion "Can not load classes with the Compiler thread"
Summary: Defer posting events from the compiler thread -- use service thread
Reviewed-by:
* * *

*** 1,7 ****
  /*
!  * Copyright (c) 2003, 2010, 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.
--- 1,7 ----
  /*
!  * 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
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
*** 32,90 ****
  #include "runtime/mutex.hpp"
  #include "runtime/mutexLocker.hpp"
  #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,
-                           vmSymbolHandles::object_initializer_name(),
-                           vmSymbolHandles::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");
    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();
--- 32,46 ----
  #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();
*** 98,136 ****
      }
    }
    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);
! 
!       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);
!       }
!     }
! 
!     {
        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();
--- 54,68 ----
      }
    }
    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();
*** 139,156 ****
          }
          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(LowMemory_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);
--- 71,86 ----
      }
      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);
*** 164,174 ****
        has_pending_requests = has_pending_requests || sensor->has_pending_requests();
      }
    }
  
    if (has_pending_requests) {
!     LowMemory_lock->notify_all();
    }
  }
  
  // This method could be called from any Java threads
  // and also VMThread.
--- 94,104 ----
        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.
*** 179,196 ****
        pool->usage_threshold()->high_threshold() == 0) {
      return;
    }
  
    {
!     MutexLockerEx ml(LowMemory_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();
      }
    }
  }
  
  // Only called by VMThread at GC time
--- 109,126 ----
        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
*** 201,218 ****
        pool->gc_usage_threshold()->high_threshold() == 0) {
      return;
    }
  
    {
!     MutexLockerEx ml(LowMemory_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();
      }
    }
  }
  
  // recompute enabled flag
--- 131,148 ----
        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
*** 382,393 ****
                              &args,
                              CHECK);
    }
  
    {
!     // Holds LowMemory_lock and update the sensor state
!     MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag);
      _sensor_on = true;
      _sensor_count += count;
      _pending_trigger_count = _pending_trigger_count - count;
    }
  }
--- 312,323 ----
                              &args,
                              CHECK);
    }
  
    {
!     // 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;
    }
  }
*** 408,419 ****
                              &args,
                              CHECK);
    }
  
    {
!     // Holds LowMemory_lock and update the sensor state
!     MutexLockerEx ml(LowMemory_lock, Mutex::_no_safepoint_check_flag);
      _sensor_on = false;
      _pending_clear_count = 0;
      _pending_trigger_count = _pending_trigger_count - count;
    }
  }
--- 338,349 ----
                              &args,
                              CHECK);
    }
  
    {
!     // 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;
    }
  }