--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/runtime/vmThread.hpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,148 @@
+/*
+ * Copyright 1998-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+//
+// Prioritized queue of VM operations.
+//
+// Encapsulates both queue management and
+// and priority policy
+//
+class VMOperationQueue : public CHeapObj {
+ 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 Thread {
+ 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; }
+
+ char* name() const { return (char*)"VM Thread"; }
+
+ // 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);
+
+ // 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;
+};