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8072439: fix for 8047720 may need more work

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Cleanup PeriodTask_lock usage. Also reviewed by varming@gmail.com.

Co-authored-by: Carsten Varming <varming@gmail.com>
Reviewed-by: dholmes, dcubed, mgronlun, coleenp
This commit is contained in:
Daniel D. Daugherty 2015-03-02 16:31:25 -08:00
parent 6465239986
commit 12cd46edc9
5 changed files with 59 additions and 40 deletions
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35
hotspot/src/share/vm/runtime/task.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2015, 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
@ -47,6 +47,8 @@ void PeriodicTask::print_intervals() {
#endif
void PeriodicTask::real_time_tick(int delay_time) {
assert(Thread::current()->is_Watcher_thread(), "must be WatcherThread");
#ifndef PRODUCT
if (ProfilerCheckIntervals) {
_ticks++;
@ -60,6 +62,8 @@ void PeriodicTask::real_time_tick(int delay_time) {
#endif
{
// The WatcherThread does not participate in the safepoint protocol
// for the PeriodicTask_lock because it is not a JavaThread.
MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
int orig_num_tasks = _num_tasks;
@ -74,8 +78,7 @@ void PeriodicTask::real_time_tick(int delay_time) {
}
int PeriodicTask::time_to_wait() {
MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
NULL : PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
if (_num_tasks == 0) {
return 0; // sleep until shutdown or a task is enrolled
@ -98,14 +101,19 @@ PeriodicTask::PeriodicTask(size_t interval_time) :
}
PeriodicTask::~PeriodicTask() {
// This PeriodicTask may have already been disenrolled by a call
// to disenroll() before the PeriodicTask was deleted.
disenroll();
}
/* enroll could be called from a JavaThread, so we have to check for
* safepoint when taking the lock to avoid deadlocking */
// enroll the current PeriodicTask
void PeriodicTask::enroll() {
MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
NULL : PeriodicTask_lock);
// Follow normal safepoint aware lock enter protocol if the caller does
// not already own the PeriodicTask_lock. Otherwise, we don't try to
// enter it again because VM internal Mutexes do not support recursion.
//
MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL
: PeriodicTask_lock);
if (_num_tasks == PeriodicTask::max_tasks) {
fatal("Overflow in PeriodicTask table");
@ -113,18 +121,21 @@ void PeriodicTask::enroll() {
_tasks[_num_tasks++] = this;
WatcherThread* thread = WatcherThread::watcher_thread();
if (thread) {
if (thread != NULL) {
thread->unpark();
} else {
WatcherThread::start();
}
}
/* disenroll could be called from a JavaThread, so we have to check for
* safepoint when taking the lock to avoid deadlocking */
// disenroll the current PeriodicTask
void PeriodicTask::disenroll() {
MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ?
NULL : PeriodicTask_lock);
// Follow normal safepoint aware lock enter protocol if the caller does
// not already own the PeriodicTask_lock. Otherwise, we don't try to
// enter it again because VM internal Mutexes do not support recursion.
//
MutexLockerEx ml(PeriodicTask_lock->owned_by_self() ? NULL
: PeriodicTask_lock);
int index;
for(index = 0; index < _num_tasks && _tasks[index] != this; index++)