jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/gcTaskManager.cpp@bca17e38de00 (annotated)

src/share/vm/gc_implementation/parallelScavenge/gcTaskManager.cpp@bca17e38de00 (annotated)

src/share/vm/gc_implementation/parallelScavenge/gcTaskManager.cpp

Tue, 09 Aug 2011 10:16:01 -0700

author: jmasa
date: Tue, 09 Aug 2011 10:16:01 -0700
changeset 3294: bca17e38de00
parent 2314: f95d63e2154a
child 3328: 6d7d0790074d
permissions: -rw-r--r--

6593758: RFE: Enhance GC ergonomics to dynamically choose ParallelGCThreads
Summary: Select number of GC threads dynamically based on heap usage and number of Java threads
Reviewed-by: johnc, ysr, jcoomes

 /*
  * Copyright (c) 2002, 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.
  *
  */
 #include "precompiled.hpp"
 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
 #include "gc_implementation/parallelScavenge/gcTaskThread.hpp"
 #include "gc_implementation/shared/adaptiveSizePolicy.hpp"
 #include "memory/allocation.hpp"
 #include "memory/allocation.inline.hpp"
 #include "runtime/mutex.hpp"
 #include "runtime/mutexLocker.hpp"
 //
 // GCTask
 //
 const char* GCTask::Kind::to_string(kind value) {
   const char* result = "unknown GCTask kind";
   switch (value) {
   default:
     result = "unknown GCTask kind";
     break;
   case unknown_task:
     result = "unknown task";
     break;
   case ordinary_task:
     result = "ordinary task";
     break;
   case barrier_task:
     result = "barrier task";
     break;
   case noop_task:
     result = "noop task";
     break;
   }
   return result;
 };
 GCTask::GCTask() :
   _kind(Kind::ordinary_task),
   _affinity(GCTaskManager::sentinel_worker()){
   initialize();
 }
 GCTask::GCTask(Kind::kind kind) :
   _kind(kind),
   _affinity(GCTaskManager::sentinel_worker()) {
   initialize();
 }
 GCTask::GCTask(uint affinity) :
   _kind(Kind::ordinary_task),
   _affinity(affinity) {
   initialize();
 }
 GCTask::GCTask(Kind::kind kind, uint affinity) :
   _kind(kind),
   _affinity(affinity) {
   initialize();
 }
 void GCTask::initialize() {
   _older = NULL;
   _newer = NULL;
 }
 void GCTask::destruct() {
   assert(older() == NULL, "shouldn't have an older task");
   assert(newer() == NULL, "shouldn't have a newer task");
   // Nothing to do.
 }
 NOT_PRODUCT(
 void GCTask::print(const char* message) const {
   tty->print(INTPTR_FORMAT " <- " INTPTR_FORMAT "(%u) -> " INTPTR_FORMAT,
              newer(), this, affinity(), older());
 }
 )
 //
 // GCTaskQueue
 //
 GCTaskQueue* GCTaskQueue::create() {
   GCTaskQueue* result = new GCTaskQueue(false);
   if (TraceGCTaskQueue) {
     tty->print_cr("GCTaskQueue::create()"
                   " returns " INTPTR_FORMAT, result);
   }
   return result;
 }
 GCTaskQueue* GCTaskQueue::create_on_c_heap() {
   GCTaskQueue* result = new(ResourceObj::C_HEAP) GCTaskQueue(true);
   if (TraceGCTaskQueue) {
     tty->print_cr("GCTaskQueue::create_on_c_heap()"
                   " returns " INTPTR_FORMAT,
                   result);
   }
   return result;
 }
 GCTaskQueue::GCTaskQueue(bool on_c_heap) :
   _is_c_heap_obj(on_c_heap) {
   initialize();
   if (TraceGCTaskQueue) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " GCTaskQueue::GCTaskQueue() constructor",
                   this);
   }
 }
 void GCTaskQueue::destruct() {
   // Nothing to do.
 }
 void GCTaskQueue::destroy(GCTaskQueue* that) {
   if (TraceGCTaskQueue) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " GCTaskQueue::destroy()"
                   "  is_c_heap_obj:  %s",
                   that,
                   that->is_c_heap_obj() ? "true" : "false");
   }
   // That instance may have been allocated as a CHeapObj,
   // in which case we have to free it explicitly.
   if (that != NULL) {
     that->destruct();
     assert(that->is_empty(), "should be empty");
     if (that->is_c_heap_obj()) {
       FreeHeap(that);
     }
   }
 }
 void GCTaskQueue::initialize() {
   set_insert_end(NULL);
   set_remove_end(NULL);
   set_length(0);
 }
 // Enqueue one task.
 void GCTaskQueue::enqueue(GCTask* task) {
   if (TraceGCTaskQueue) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " GCTaskQueue::enqueue(task: "
                   INTPTR_FORMAT ")",
                   this, task);
     print("before:");
   }
   assert(task != NULL, "shouldn't have null task");
   assert(task->older() == NULL, "shouldn't be on queue");
   assert(task->newer() == NULL, "shouldn't be on queue");
   task->set_newer(NULL);
   task->set_older(insert_end());
   if (is_empty()) {
     set_remove_end(task);
   } else {
     insert_end()->set_newer(task);
   }
   set_insert_end(task);
   increment_length();
   verify_length();
   if (TraceGCTaskQueue) {
     print("after:");
   }
 }
 // Enqueue a whole list of tasks.  Empties the argument list.
 void GCTaskQueue::enqueue(GCTaskQueue* list) {
   if (TraceGCTaskQueue) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " GCTaskQueue::enqueue(list: "
                   INTPTR_FORMAT ")",
                   this, list);
     print("before:");
     list->print("list:");
   }
   if (list->is_empty()) {
     // Enqueuing the empty list: nothing to do.
     return;
   }
   uint list_length = list->length();
   if (is_empty()) {
     // Enqueuing to empty list: just acquire elements.
     set_insert_end(list->insert_end());
     set_remove_end(list->remove_end());
     set_length(list_length);
   } else {
     // Prepend argument list to our queue.
     list->remove_end()->set_older(insert_end());
     insert_end()->set_newer(list->remove_end());
     set_insert_end(list->insert_end());
     set_length(length() + list_length);
     // empty the argument list.
   }
   list->initialize();
   if (TraceGCTaskQueue) {
     print("after:");
     list->print("list:");
   }
   verify_length();
 }
 // Dequeue one task.
 GCTask* GCTaskQueue::dequeue() {
   if (TraceGCTaskQueue) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " GCTaskQueue::dequeue()", this);
     print("before:");
   }
   assert(!is_empty(), "shouldn't dequeue from empty list");
   GCTask* result = remove();
   assert(result != NULL, "shouldn't have NULL task");
   if (TraceGCTaskQueue) {
     tty->print_cr("    return: " INTPTR_FORMAT, result);
     print("after:");
   }
   return result;
 }
 // Dequeue one task, preferring one with affinity.
 GCTask* GCTaskQueue::dequeue(uint affinity) {
   if (TraceGCTaskQueue) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " GCTaskQueue::dequeue(%u)", this, affinity);
     print("before:");
   }
   assert(!is_empty(), "shouldn't dequeue from empty list");
   // Look down to the next barrier for a task with this affinity.
   GCTask* result = NULL;
   for (GCTask* element = remove_end();
        element != NULL;
        element = element->newer()) {
     if (element->is_barrier_task()) {
       // Don't consider barrier tasks, nor past them.
       result = NULL;
       break;
     }
     if (element->affinity() == affinity) {
       result = remove(element);
       break;
     }
   }
   // If we didn't find anything with affinity, just take the next task.
   if (result == NULL) {
     result = remove();
   }
   if (TraceGCTaskQueue) {
     tty->print_cr("    return: " INTPTR_FORMAT, result);
     print("after:");
   }
   return result;
 }
 GCTask* GCTaskQueue::remove() {
   // Dequeue from remove end.
   GCTask* result = remove_end();
   assert(result != NULL, "shouldn't have null task");
   assert(result->older() == NULL, "not the remove_end");
   set_remove_end(result->newer());
   if (remove_end() == NULL) {
     assert(insert_end() == result, "not a singleton");
     set_insert_end(NULL);
   } else {
     remove_end()->set_older(NULL);
   }
   result->set_newer(NULL);
   decrement_length();
   assert(result->newer() == NULL, "shouldn't be on queue");
   assert(result->older() == NULL, "shouldn't be on queue");
   verify_length();
   return result;
 }
 GCTask* GCTaskQueue::remove(GCTask* task) {
   // This is slightly more work, and has slightly fewer asserts
   // than removing from the remove end.
   assert(task != NULL, "shouldn't have null task");
   GCTask* result = task;
   if (result->newer() != NULL) {
     result->newer()->set_older(result->older());
   } else {
     assert(insert_end() == result, "not youngest");
     set_insert_end(result->older());
   }
   if (result->older() != NULL) {
     result->older()->set_newer(result->newer());
   } else {
     assert(remove_end() == result, "not oldest");
     set_remove_end(result->newer());
   }
   result->set_newer(NULL);
   result->set_older(NULL);
   decrement_length();
   verify_length();
   return result;
 }
 NOT_PRODUCT(
 // Count the elements in the queue and verify the length against
 // that count.
 void GCTaskQueue::verify_length() const {
   uint count = 0;
   for (GCTask* element = insert_end();
        element != NULL;
        element = element->older()) {
     count++;
   }
   assert(count == length(), "Length does not match queue");
 }
 void GCTaskQueue::print(const char* message) const {
   tty->print_cr("[" INTPTR_FORMAT "] GCTaskQueue:"
                 "  insert_end: " INTPTR_FORMAT
                 "  remove_end: " INTPTR_FORMAT
                 "  length:       %d"
                 "  %s",
                 this, insert_end(), remove_end(), length(), message);
   uint count = 0;
   for (GCTask* element = insert_end();
        element != NULL;
        element = element->older()) {
     element->print("    ");
     count++;
     tty->cr();
   }
   tty->print("Total tasks: %d", count);
 }
 )
 //
 // SynchronizedGCTaskQueue
 //
 SynchronizedGCTaskQueue::SynchronizedGCTaskQueue(GCTaskQueue* queue_arg,
                                                  Monitor *       lock_arg) :
   _unsynchronized_queue(queue_arg),
   _lock(lock_arg) {
   assert(unsynchronized_queue() != NULL, "null queue");
   assert(lock() != NULL, "null lock");
 }
 SynchronizedGCTaskQueue::~SynchronizedGCTaskQueue() {
   // Nothing to do.
 }
 //
 // GCTaskManager
 //
 GCTaskManager::GCTaskManager(uint workers) :
   _workers(workers),
   _active_workers(0),
   _idle_workers(0),
   _ndc(NULL) {
   initialize();
 }
 GCTaskManager::GCTaskManager(uint workers, NotifyDoneClosure* ndc) :
   _workers(workers),
   _active_workers(0),
   _idle_workers(0),
   _ndc(ndc) {
   initialize();
 }
 void GCTaskManager::initialize() {
   if (TraceGCTaskManager) {
     tty->print_cr("GCTaskManager::initialize: workers: %u", workers());
   }
   assert(workers() != 0, "no workers");
   _monitor = new Monitor(Mutex::barrier,                // rank
                          "GCTaskManager monitor",       // name
                          Mutex::_allow_vm_block_flag);  // allow_vm_block
   // The queue for the GCTaskManager must be a CHeapObj.
   GCTaskQueue* unsynchronized_queue = GCTaskQueue::create_on_c_heap();
   _queue = SynchronizedGCTaskQueue::create(unsynchronized_queue, lock());
   _noop_task = NoopGCTask::create_on_c_heap();
   _idle_inactive_task = WaitForBarrierGCTask::create_on_c_heap();
   _resource_flag = NEW_C_HEAP_ARRAY(bool, workers());
   {
     // Set up worker threads.
     //     Distribute the workers among the available processors,
     //     unless we were told not to, or if the os doesn't want to.
     uint* processor_assignment = NEW_C_HEAP_ARRAY(uint, workers());
     if (!BindGCTaskThreadsToCPUs ||
         !os::distribute_processes(workers(), processor_assignment)) {
       for (uint a = 0; a < workers(); a += 1) {
         processor_assignment[a] = sentinel_worker();
       }
     }
     _thread = NEW_C_HEAP_ARRAY(GCTaskThread*, workers());
     for (uint t = 0; t < workers(); t += 1) {
       set_thread(t, GCTaskThread::create(this, t, processor_assignment[t]));
     }
     if (TraceGCTaskThread) {
       tty->print("GCTaskManager::initialize: distribution:");
       for (uint t = 0; t < workers(); t += 1) {
         tty->print("  %u", processor_assignment[t]);
       }
       tty->cr();
     }
     FREE_C_HEAP_ARRAY(uint, processor_assignment);
   }
   reset_busy_workers();
   set_unblocked();
   for (uint w = 0; w < workers(); w += 1) {
     set_resource_flag(w, false);
   }
   reset_delivered_tasks();
   reset_completed_tasks();
   reset_noop_tasks();
   reset_barriers();
   reset_emptied_queue();
   for (uint s = 0; s < workers(); s += 1) {
     thread(s)->start();
   }
 }
 GCTaskManager::~GCTaskManager() {
   assert(busy_workers() == 0, "still have busy workers");
   assert(queue()->is_empty(), "still have queued work");
   NoopGCTask::destroy(_noop_task);
   _noop_task = NULL;
   WaitForBarrierGCTask::destroy(_idle_inactive_task);
   _idle_inactive_task = NULL;
   if (_thread != NULL) {
     for (uint i = 0; i < workers(); i += 1) {
       GCTaskThread::destroy(thread(i));
       set_thread(i, NULL);
     }
     FREE_C_HEAP_ARRAY(GCTaskThread*, _thread);
     _thread = NULL;
   }
   if (_resource_flag != NULL) {
     FREE_C_HEAP_ARRAY(bool, _resource_flag);
     _resource_flag = NULL;
   }
   if (queue() != NULL) {
     GCTaskQueue* unsynchronized_queue = queue()->unsynchronized_queue();
     GCTaskQueue::destroy(unsynchronized_queue);
     SynchronizedGCTaskQueue::destroy(queue());
     _queue = NULL;
   }
   if (monitor() != NULL) {
     delete monitor();
     _monitor = NULL;
   }
 }
 void GCTaskManager::set_active_gang() {
   _active_workers =
     AdaptiveSizePolicy::calc_active_workers(workers(),
                                  active_workers(),
                                  Threads::number_of_non_daemon_threads());
   assert(!all_workers_active() || active_workers() == ParallelGCThreads,
          err_msg("all_workers_active() is  incorrect: "
                  "active %d  ParallelGCThreads %d", active_workers(),
                  ParallelGCThreads));
   if (TraceDynamicGCThreads) {
     gclog_or_tty->print_cr("GCTaskManager::set_active_gang(): "
                            "all_workers_active()  %d  workers %d  "
                            "active  %d  ParallelGCThreads %d ",
                            all_workers_active(), workers(),  active_workers(),
                            ParallelGCThreads);
   }
 }
 // Create IdleGCTasks for inactive workers.
 // Creates tasks in a ResourceArea and assumes
 // an appropriate ResourceMark.
 void GCTaskManager::task_idle_workers() {
   {
     int more_inactive_workers = 0;
     {
       // Stop any idle tasks from exiting their IdleGCTask's
       // and get the count for additional IdleGCTask's under
       // the GCTaskManager's monitor so that the "more_inactive_workers"
       // count is correct.
       MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
       _idle_inactive_task->set_should_wait(true);
       // active_workers are a number being requested.  idle_workers
       // are the number currently idle.  If all the workers are being
       // requested to be active but some are already idle, reduce
       // the number of active_workers to be consistent with the
       // number of idle_workers.  The idle_workers are stuck in
       // idle tasks and will no longer be release (since a new GC
       // is starting).  Try later to release enough idle_workers
       // to allow the desired number of active_workers.
       more_inactive_workers =
         workers() - active_workers() - idle_workers();
       if (more_inactive_workers < 0) {
         int reduced_active_workers = active_workers() + more_inactive_workers;
         set_active_workers(reduced_active_workers);
         more_inactive_workers = 0;
       }
       if (TraceDynamicGCThreads) {
         gclog_or_tty->print_cr("JT: %d  workers %d  active  %d  "
                                 "idle %d  more %d",
                                 Threads::number_of_non_daemon_threads(),
                                 workers(),
                                 active_workers(),
                                 idle_workers(),
                                 more_inactive_workers);
       }
     }
     GCTaskQueue* q = GCTaskQueue::create();
     for(uint i = 0; i < (uint) more_inactive_workers; i++) {
       q->enqueue(IdleGCTask::create_on_c_heap());
       increment_idle_workers();
     }
     assert(workers() == active_workers() + idle_workers(),
       "total workers should equal active + inactive");
     add_list(q);
     // GCTaskQueue* q was created in a ResourceArea so a
     // destroy() call is not needed.
   }
 }
 void  GCTaskManager::release_idle_workers() {
   {
     MutexLockerEx ml(monitor(),
       Mutex::_no_safepoint_check_flag);
     _idle_inactive_task->set_should_wait(false);
     monitor()->notify_all();
   // Release monitor
   }
 }
 void GCTaskManager::print_task_time_stamps() {
   for(uint i=0; i<ParallelGCThreads; i++) {
     GCTaskThread* t = thread(i);
     t->print_task_time_stamps();
   }
 }
 void GCTaskManager::print_threads_on(outputStream* st) {
   uint num_thr = workers();
   for (uint i = 0; i < num_thr; i++) {
     thread(i)->print_on(st);
     st->cr();
   }
 }
 void GCTaskManager::threads_do(ThreadClosure* tc) {
   assert(tc != NULL, "Null ThreadClosure");
   uint num_thr = workers();
   for (uint i = 0; i < num_thr; i++) {
     tc->do_thread(thread(i));
   }
 }
 GCTaskThread* GCTaskManager::thread(uint which) {
   assert(which < workers(), "index out of bounds");
   assert(_thread[which] != NULL, "shouldn't have null thread");
   return _thread[which];
 }
 void GCTaskManager::set_thread(uint which, GCTaskThread* value) {
   assert(which < workers(), "index out of bounds");
   assert(value != NULL, "shouldn't have null thread");
   _thread[which] = value;
 }
 void GCTaskManager::add_task(GCTask* task) {
   assert(task != NULL, "shouldn't have null task");
   MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
   if (TraceGCTaskManager) {
     tty->print_cr("GCTaskManager::add_task(" INTPTR_FORMAT " [%s])",
                   task, GCTask::Kind::to_string(task->kind()));
   }
   queue()->enqueue(task);
   // Notify with the lock held to avoid missed notifies.
   if (TraceGCTaskManager) {
     tty->print_cr("    GCTaskManager::add_task (%s)->notify_all",
                   monitor()->name());
   }
   (void) monitor()->notify_all();
   // Release monitor().
 }
 void GCTaskManager::add_list(GCTaskQueue* list) {
   assert(list != NULL, "shouldn't have null task");
   MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
   if (TraceGCTaskManager) {
     tty->print_cr("GCTaskManager::add_list(%u)", list->length());
   }
   queue()->enqueue(list);
   // Notify with the lock held to avoid missed notifies.
   if (TraceGCTaskManager) {
     tty->print_cr("    GCTaskManager::add_list (%s)->notify_all",
                   monitor()->name());
   }
   (void) monitor()->notify_all();
   // Release monitor().
 }
 // GC workers wait in get_task() for new work to be added
 // to the GCTaskManager's queue.  When new work is added,
 // a notify is sent to the waiting GC workers which then
 // compete to get tasks.  If a GC worker wakes up and there
 // is no work on the queue, it is given a noop_task to execute
 // and then loops to find more work.
 GCTask* GCTaskManager::get_task(uint which) {
   GCTask* result = NULL;
   // Grab the queue lock.
   MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
   // Wait while the queue is block or
   // there is nothing to do, except maybe release resources.
   while (is_blocked() ||
          (queue()->is_empty() && !should_release_resources(which))) {
     if (TraceGCTaskManager) {
       tty->print_cr("GCTaskManager::get_task(%u)"
                     "  blocked: %s"
                     "  empty: %s"
                     "  release: %s",
                     which,
                     is_blocked() ? "true" : "false",
                     queue()->is_empty() ? "true" : "false",
                     should_release_resources(which) ? "true" : "false");
       tty->print_cr("    => (%s)->wait()",
                     monitor()->name());
     }
     monitor()->wait(Mutex::_no_safepoint_check_flag, 0);
   }
   // We've reacquired the queue lock here.
   // Figure out which condition caused us to exit the loop above.
   if (!queue()->is_empty()) {
     if (UseGCTaskAffinity) {
       result = queue()->dequeue(which);
     } else {
       result = queue()->dequeue();
     }
     if (result->is_barrier_task()) {
       assert(which != sentinel_worker(),
              "blocker shouldn't be bogus");
       set_blocking_worker(which);
     }
   } else {
     // The queue is empty, but we were woken up.
     // Just hand back a Noop task,
     // in case someone wanted us to release resources, or whatever.
     result = noop_task();
     increment_noop_tasks();
   }
   assert(result != NULL, "shouldn't have null task");
   if (TraceGCTaskManager) {
     tty->print_cr("GCTaskManager::get_task(%u) => " INTPTR_FORMAT " [%s]",
                   which, result, GCTask::Kind::to_string(result->kind()));
     tty->print_cr("     %s", result->name());
   }
   if (!result->is_idle_task()) {
     increment_busy_workers();
     increment_delivered_tasks();
   }
   return result;
   // Release monitor().
 }
 void GCTaskManager::note_completion(uint which) {
   MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
   if (TraceGCTaskManager) {
     tty->print_cr("GCTaskManager::note_completion(%u)", which);
   }
   // If we are blocked, check if the completing thread is the blocker.
   if (blocking_worker() == which) {
     assert(blocking_worker() != sentinel_worker(),
            "blocker shouldn't be bogus");
     increment_barriers();
     set_unblocked();
   }
   increment_completed_tasks();
   uint active = decrement_busy_workers();
   if ((active == 0) && (queue()->is_empty())) {
     increment_emptied_queue();
     if (TraceGCTaskManager) {
       tty->print_cr("    GCTaskManager::note_completion(%u) done", which);
     }
     // Notify client that we are done.
     NotifyDoneClosure* ndc = notify_done_closure();
     if (ndc != NULL) {
       ndc->notify(this);
     }
   }
   if (TraceGCTaskManager) {
     tty->print_cr("    GCTaskManager::note_completion(%u) (%s)->notify_all",
                   which, monitor()->name());
     tty->print_cr("  "
                   "  blocked: %s"
                   "  empty: %s"
                   "  release: %s",
                   is_blocked() ? "true" : "false",
                   queue()->is_empty() ? "true" : "false",
                   should_release_resources(which) ? "true" : "false");
     tty->print_cr("  "
                   "  delivered: %u"
                   "  completed: %u"
                   "  barriers: %u"
                   "  emptied: %u",
                   delivered_tasks(),
                   completed_tasks(),
                   barriers(),
                   emptied_queue());
   }
   // Tell everyone that a task has completed.
   (void) monitor()->notify_all();
   // Release monitor().
 }
 uint GCTaskManager::increment_busy_workers() {
   assert(queue()->own_lock(), "don't own the lock");
   _busy_workers += 1;
   return _busy_workers;
 }
 uint GCTaskManager::decrement_busy_workers() {
   assert(queue()->own_lock(), "don't own the lock");
   assert(_busy_workers > 0, "About to make a mistake");
   _busy_workers -= 1;
   return _busy_workers;
 }
 void GCTaskManager::release_all_resources() {
   // If you want this to be done atomically, do it in a BarrierGCTask.
   for (uint i = 0; i < workers(); i += 1) {
     set_resource_flag(i, true);
   }
 }
 bool GCTaskManager::should_release_resources(uint which) {
   // This can be done without a lock because each thread reads one element.
   return resource_flag(which);
 }
 void GCTaskManager::note_release(uint which) {
   // This can be done without a lock because each thread writes one element.
   set_resource_flag(which, false);
 }
 // "list" contains tasks that are ready to execute.  Those
 // tasks are added to the GCTaskManager's queue of tasks and
 // then the GC workers are notified that there is new work to
 // do.
 //
 // Typically different types of tasks can be added to the "list".
 // For example in PSScavenge OldToYoungRootsTask, SerialOldToYoungRootsTask,
 // ScavengeRootsTask, and StealTask tasks are all added to the list
 // and then the GC workers are notified of new work.  The tasks are
 // handed out in the order in which they are added to the list
 // (although execution is not necessarily in that order).  As long
 // as any tasks are running the GCTaskManager will wait for execution
 // to complete.  GC workers that execute a stealing task remain in
 // the stealing task until all stealing tasks have completed.  The load
 // balancing afforded by the stealing tasks work best if the stealing
 // tasks are added last to the list.
 void GCTaskManager::execute_and_wait(GCTaskQueue* list) {
   WaitForBarrierGCTask* fin = WaitForBarrierGCTask::create();
   list->enqueue(fin);
   add_list(list);
   fin->wait_for(true /* reset */);
   // We have to release the barrier tasks!
   WaitForBarrierGCTask::destroy(fin);
 }
 bool GCTaskManager::resource_flag(uint which) {
   assert(which < workers(), "index out of bounds");
   return _resource_flag[which];
 }
 void GCTaskManager::set_resource_flag(uint which, bool value) {
   assert(which < workers(), "index out of bounds");
   _resource_flag[which] = value;
 }
 //
 // NoopGCTask
 //
 NoopGCTask* NoopGCTask::create() {
   NoopGCTask* result = new NoopGCTask(false);
   return result;
 }
 NoopGCTask* NoopGCTask::create_on_c_heap() {
   NoopGCTask* result = new(ResourceObj::C_HEAP) NoopGCTask(true);
   return result;
 }
 void NoopGCTask::destroy(NoopGCTask* that) {
   if (that != NULL) {
     that->destruct();
     if (that->is_c_heap_obj()) {
       FreeHeap(that);
     }
   }
 }
 void NoopGCTask::destruct() {
   // This has to know it's superclass structure, just like the constructor.
   this->GCTask::destruct();
   // Nothing else to do.
 }
 //
 // IdleGCTask
 //
 IdleGCTask* IdleGCTask::create() {
   IdleGCTask* result = new IdleGCTask(false);
   return result;
 }
 IdleGCTask* IdleGCTask::create_on_c_heap() {
   IdleGCTask* result = new(ResourceObj::C_HEAP) IdleGCTask(true);
   return result;
 }
 void IdleGCTask::do_it(GCTaskManager* manager, uint which) {
   WaitForBarrierGCTask* wait_for_task = manager->idle_inactive_task();
   if (TraceGCTaskManager) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " IdleGCTask:::do_it()"
       "  should_wait: %s",
       this, wait_for_task->should_wait() ? "true" : "false");
   }
   MutexLockerEx ml(manager->monitor(), Mutex::_no_safepoint_check_flag);
   if (TraceDynamicGCThreads) {
     gclog_or_tty->print_cr("--- idle %d", which);
   }
   // Increment has to be done when the idle tasks are created.
   // manager->increment_idle_workers();
   manager->monitor()->notify_all();
   while (wait_for_task->should_wait()) {
     if (TraceGCTaskManager) {
       tty->print_cr("[" INTPTR_FORMAT "]"
                     " IdleGCTask::do_it()"
         "  [" INTPTR_FORMAT "] (%s)->wait()",
         this, manager->monitor(), manager->monitor()->name());
     }
     manager->monitor()->wait(Mutex::_no_safepoint_check_flag, 0);
   }
   manager->decrement_idle_workers();
   if (TraceDynamicGCThreads) {
     gclog_or_tty->print_cr("--- release %d", which);
   }
   if (TraceGCTaskManager) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " IdleGCTask::do_it() returns"
       "  should_wait: %s",
       this, wait_for_task->should_wait() ? "true" : "false");
   }
   // Release monitor().
 }
 void IdleGCTask::destroy(IdleGCTask* that) {
   if (that != NULL) {
     that->destruct();
     if (that->is_c_heap_obj()) {
       FreeHeap(that);
     }
   }
 }
 void IdleGCTask::destruct() {
   // This has to know it's superclass structure, just like the constructor.
   this->GCTask::destruct();
   // Nothing else to do.
 }
 //
 // BarrierGCTask
 //
 void BarrierGCTask::do_it(GCTaskManager* manager, uint which) {
   // Wait for this to be the only busy worker.
   // ??? I thought of having a StackObj class
   //     whose constructor would grab the lock and come to the barrier,
   //     and whose destructor would release the lock,
   //     but that seems like too much mechanism for two lines of code.
   MutexLockerEx ml(manager->lock(), Mutex::_no_safepoint_check_flag);
   do_it_internal(manager, which);
   // Release manager->lock().
 }
 void BarrierGCTask::do_it_internal(GCTaskManager* manager, uint which) {
   // Wait for this to be the only busy worker.
   assert(manager->monitor()->owned_by_self(), "don't own the lock");
   assert(manager->is_blocked(), "manager isn't blocked");
   while (manager->busy_workers() > 1) {
     if (TraceGCTaskManager) {
       tty->print_cr("BarrierGCTask::do_it(%u) waiting on %u workers",
                     which, manager->busy_workers());
     }
     manager->monitor()->wait(Mutex::_no_safepoint_check_flag, 0);
   }
 }
 void BarrierGCTask::destruct() {
   this->GCTask::destruct();
   // Nothing else to do.
 }
 //
 // ReleasingBarrierGCTask
 //
 void ReleasingBarrierGCTask::do_it(GCTaskManager* manager, uint which) {
   MutexLockerEx ml(manager->lock(), Mutex::_no_safepoint_check_flag);
   do_it_internal(manager, which);
   manager->release_all_resources();
   // Release manager->lock().
 }
 void ReleasingBarrierGCTask::destruct() {
   this->BarrierGCTask::destruct();
   // Nothing else to do.
 }
 //
 // NotifyingBarrierGCTask
 //
 void NotifyingBarrierGCTask::do_it(GCTaskManager* manager, uint which) {
   MutexLockerEx ml(manager->lock(), Mutex::_no_safepoint_check_flag);
   do_it_internal(manager, which);
   NotifyDoneClosure* ndc = notify_done_closure();
   if (ndc != NULL) {
     ndc->notify(manager);
   }
   // Release manager->lock().
 }
 void NotifyingBarrierGCTask::destruct() {
   this->BarrierGCTask::destruct();
   // Nothing else to do.
 }
 //
 // WaitForBarrierGCTask
 //
 WaitForBarrierGCTask* WaitForBarrierGCTask::create() {
   WaitForBarrierGCTask* result = new WaitForBarrierGCTask(false);
   return result;
 }
 WaitForBarrierGCTask* WaitForBarrierGCTask::create_on_c_heap() {
   WaitForBarrierGCTask* result =
     new (ResourceObj::C_HEAP) WaitForBarrierGCTask(true);
   return result;
 }
 WaitForBarrierGCTask::WaitForBarrierGCTask(bool on_c_heap) :
   _is_c_heap_obj(on_c_heap) {
   _monitor = MonitorSupply::reserve();
   set_should_wait(true);
   if (TraceGCTaskManager) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " WaitForBarrierGCTask::WaitForBarrierGCTask()"
                   "  monitor: " INTPTR_FORMAT,
                   this, monitor());
   }
 }
 void WaitForBarrierGCTask::destroy(WaitForBarrierGCTask* that) {
   if (that != NULL) {
     if (TraceGCTaskManager) {
       tty->print_cr("[" INTPTR_FORMAT "]"
                     " WaitForBarrierGCTask::destroy()"
                     "  is_c_heap_obj: %s"
                     "  monitor: " INTPTR_FORMAT,
                     that,
                     that->is_c_heap_obj() ? "true" : "false",
                     that->monitor());
     }
     that->destruct();
     if (that->is_c_heap_obj()) {
       FreeHeap(that);
     }
   }
 }
 void WaitForBarrierGCTask::destruct() {
   assert(monitor() != NULL, "monitor should not be NULL");
   if (TraceGCTaskManager) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " WaitForBarrierGCTask::destruct()"
                   "  monitor: " INTPTR_FORMAT,
                   this, monitor());
   }
   this->BarrierGCTask::destruct();
   // Clean up that should be in the destructor,
   // except that ResourceMarks don't call destructors.
    if (monitor() != NULL) {
      MonitorSupply::release(monitor());
   }
   _monitor = (Monitor*) 0xDEAD000F;
 }
 void WaitForBarrierGCTask::do_it(GCTaskManager* manager, uint which) {
   if (TraceGCTaskManager) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " WaitForBarrierGCTask::do_it() waiting for idle"
                   "  monitor: " INTPTR_FORMAT,
                   this, monitor());
   }
   {
     // First, wait for the barrier to arrive.
     MutexLockerEx ml(manager->lock(), Mutex::_no_safepoint_check_flag);
     do_it_internal(manager, which);
     // Release manager->lock().
   }
   {
     // Then notify the waiter.
     MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
     set_should_wait(false);
     // Waiter doesn't miss the notify in the wait_for method
     // since it checks the flag after grabbing the monitor.
     if (TraceGCTaskManager) {
       tty->print_cr("[" INTPTR_FORMAT "]"
                     " WaitForBarrierGCTask::do_it()"
                     "  [" INTPTR_FORMAT "] (%s)->notify_all()",
                     this, monitor(), monitor()->name());
     }
     monitor()->notify_all();
     // Release monitor().
   }
 }
 void WaitForBarrierGCTask::wait_for(bool reset) {
   if (TraceGCTaskManager) {
     tty->print_cr("[" INTPTR_FORMAT "]"
                   " WaitForBarrierGCTask::wait_for()"
       "  should_wait: %s",
       this, should_wait() ? "true" : "false");
   }
   {
     // Grab the lock and check again.
     MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
     while (should_wait()) {
       if (TraceGCTaskManager) {
         tty->print_cr("[" INTPTR_FORMAT "]"
                       " WaitForBarrierGCTask::wait_for()"
           "  [" INTPTR_FORMAT "] (%s)->wait()",
           this, monitor(), monitor()->name());
       }
       monitor()->wait(Mutex::_no_safepoint_check_flag, 0);
     }
     // Reset the flag in case someone reuses this task.
     if (reset) {
       set_should_wait(true);
     }
     if (TraceGCTaskManager) {
       tty->print_cr("[" INTPTR_FORMAT "]"
                     " WaitForBarrierGCTask::wait_for() returns"
         "  should_wait: %s",
         this, should_wait() ? "true" : "false");
     }
     // Release monitor().
   }
 }
 Mutex*                   MonitorSupply::_lock     = NULL;
 GrowableArray<Monitor*>* MonitorSupply::_freelist = NULL;
 Monitor* MonitorSupply::reserve() {
   Monitor* result = NULL;
   // Lazy initialization: possible race.
   if (lock() == NULL) {
     _lock = new Mutex(Mutex::barrier,                  // rank
                       "MonitorSupply mutex",           // name
                       Mutex::_allow_vm_block_flag);    // allow_vm_block
   }
   {
     MutexLockerEx ml(lock());
     // Lazy initialization.
     if (freelist() == NULL) {
       _freelist =
         new(ResourceObj::C_HEAP) GrowableArray<Monitor*>(ParallelGCThreads,
                                                          true);
     }
     if (! freelist()->is_empty()) {
       result = freelist()->pop();
     } else {
       result = new Monitor(Mutex::barrier,                  // rank
                            "MonitorSupply monitor",         // name
                            Mutex::_allow_vm_block_flag);    // allow_vm_block
     }
     guarantee(result != NULL, "shouldn't return NULL");
     assert(!result->is_locked(), "shouldn't be locked");
     // release lock().
   }
   return result;
 }
 void MonitorSupply::release(Monitor* instance) {
   assert(instance != NULL, "shouldn't release NULL");
   assert(!instance->is_locked(), "shouldn't be locked");
   {
     MutexLockerEx ml(lock());
     freelist()->push(instance);
     // release lock().
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/gcTaskManager.cpp@bca17e38de00 (annotated)

src/share/vm/gc_implementation/parallelScavenge/gcTaskManager.cpp