| /* |
| * Copyright (c) 1998, 2016, 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/thread.hpp" |
| #include "runtime/vm_operations.hpp" |
| |
| // |
| // 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; |
| |
| static const char* _no_op_reason; |
| |
| static bool no_op_safepoint_needed(bool check_time); |
| |
| void evaluate_operation(VM_Operation* op); |
| |
| public: |
| // Constructor |
| VMThread(); |
| |
| // No destruction allowed |
| ~VMThread() { |
| guarantee(false, "VMThread deletion must fix the race with VM termination"); |
| } |
| |
| |
| // 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 current vm operation name or set reason |
| static const char* vm_safepoint_description() { return _cur_vm_operation != NULL ? _cur_vm_operation->name() : _no_op_reason; }; |
| |
| // Returns the single instance of VMThread. |
| static VMThread* vm_thread() { return _vm_thread; } |
| |
| // GC support |
| void oops_do(OopClosure* f, CodeBlobClosure* cf); |
| |
| 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 |