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/*
* Copyright (c) 1998, 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.
*
* 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.
*
*/
#ifndef SHARE_VM_RUNTIME_VMTHREAD_HPP
#define SHARE_VM_RUNTIME_VMTHREAD_HPP
#include "runtime/perfData.hpp"
#include "runtime/vm_operations.hpp"
#ifdef TARGET_OS_FAMILY_linux
# include "thread_linux.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_solaris
# include "thread_solaris.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_windows
# include "thread_windows.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_bsd
# include "thread_bsd.inline.hpp"
#endif
//
// Prioritized queue of VM operations.
//
// Encapsulates both queue management and
// and priority policy
//
class VMOperationQueue : public CHeapObj<mtInternal> {
private:
enum Priorities {
SafepointPriority, // Highest priority (operation executed at a safepoint)
MediumPriority, // Medium priority
nof_priorities
};
// We maintain a doubled linked list, with explicit count.
int _queue_length[nof_priorities];
int _queue_counter;
VM_Operation* _queue [nof_priorities];
// we also allow the vmThread to register the ops it has drained so we
// can scan them from oops_do
VM_Operation* _drain_list;
// Double-linked non-empty list insert.
void insert(VM_Operation* q,VM_Operation* n);
void unlink(VM_Operation* q);
// Basic queue manipulation
bool queue_empty (int prio);
void queue_add_front (int prio, VM_Operation *op);
void queue_add_back (int prio, VM_Operation *op);
VM_Operation* queue_remove_front(int prio);
void queue_oops_do(int queue, OopClosure* f);
void drain_list_oops_do(OopClosure* f);
VM_Operation* queue_drain(int prio);
// lock-free query: may return the wrong answer but must not break
bool queue_peek(int prio) { return _queue_length[prio] > 0; }
public:
VMOperationQueue();
// Highlevel operations. Encapsulates policy
bool add(VM_Operation *op);
VM_Operation* remove_next(); // Returns next or null
VM_Operation* remove_next_at_safepoint_priority() { return queue_remove_front(SafepointPriority); }
VM_Operation* drain_at_safepoint_priority() { return queue_drain(SafepointPriority); }
void set_drain_list(VM_Operation* list) { _drain_list = list; }
bool peek_at_safepoint_priority() { return queue_peek(SafepointPriority); }
// GC support
void oops_do(OopClosure* f);
void verify_queue(int prio) PRODUCT_RETURN;
};
//
// A single VMThread (the primordial thread) spawns all other threads
// and is itself used by other threads to offload heavy vm operations
// like scavenge, garbage_collect etc.
//
class VMThread: public NamedThread {
private:
static ThreadPriority _current_priority;
static bool _should_terminate;
static bool _terminated;
static Monitor * _terminate_lock;
static PerfCounter* _perf_accumulated_vm_operation_time;
void evaluate_operation(VM_Operation* op);
public:
// Constructor
VMThread();
// Tester
bool is_VM_thread() const { return true; }
bool is_GC_thread() const { return true; }
// The ever running loop for the VMThread
void loop();
// Called to stop the VM thread
static void wait_for_vm_thread_exit();
static bool should_terminate() { return _should_terminate; }
static bool is_terminated() { return _terminated == true; }
// Execution of vm operation
static void execute(VM_Operation* op);
// Returns the current vm operation if any.
static VM_Operation* vm_operation() { return _cur_vm_operation; }
// Returns the single instance of VMThread.
static VMThread* vm_thread() { return _vm_thread; }
// GC support
void oops_do(OopClosure* f, CodeBlobClosure* cf);
// Debugging
void print_on(outputStream* st) const;
void print() const { print_on(tty); }
void verify();
// Performance measurement
static PerfCounter* perf_accumulated_vm_operation_time() { return _perf_accumulated_vm_operation_time; }
// Entry for starting vm thread
virtual void run();
// Creations/Destructions
static void create();
static void destroy();
private:
// VM_Operation support
static VM_Operation* _cur_vm_operation; // Current VM operation
static VMOperationQueue* _vm_queue; // Queue (w/ policy) of VM operations
// Pointer to single-instance of VM thread
static VMThread* _vm_thread;
};
#endif // SHARE_VM_RUNTIME_VMTHREAD_HPP
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