Mercurial > hg > graal-compiler
view src/share/vm/runtime/task.cpp @ 452:00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery.
Reviewed-by: apetrusenko, jcoomes
author | ysr |
---|---|
date | Thu, 20 Nov 2008 12:27:41 -0800 |
parents | 1ee8caae33af |
children | c18cbe5936b8 |
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/* * Copyright 1997-2008 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. * */ # include "incls/_precompiled.incl" # include "incls/_task.cpp.incl" int PeriodicTask::_num_tasks = 0; PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks]; #ifndef PRODUCT elapsedTimer PeriodicTask::_timer; int PeriodicTask::_intervalHistogram[PeriodicTask::max_interval]; int PeriodicTask::_ticks; void PeriodicTask::print_intervals() { if (ProfilerCheckIntervals) { for (int i = 0; i < PeriodicTask::max_interval; i++) { int n = _intervalHistogram[i]; if (n > 0) tty->print_cr("%3d: %5d (%4.1f%%)", i, n, 100.0 * n / _ticks); } } } #endif void PeriodicTask::real_time_tick(size_t delay_time) { #ifndef PRODUCT if (ProfilerCheckIntervals) { _ticks++; _timer.stop(); int ms = (int)(_timer.seconds() * 1000.0); _timer.reset(); _timer.start(); if (ms >= PeriodicTask::max_interval) ms = PeriodicTask::max_interval - 1; _intervalHistogram[ms]++; } #endif int orig_num_tasks = _num_tasks; for(int index = 0; index < _num_tasks; index++) { _tasks[index]->execute_if_pending(delay_time); if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself index--; // re-do current slot as it has changed orig_num_tasks = _num_tasks; } } } PeriodicTask::PeriodicTask(size_t interval_time) : _counter(0), _interval(interval_time) { // Sanity check the interval time assert(_interval >= PeriodicTask::min_interval && _interval <= PeriodicTask::max_interval && _interval % PeriodicTask::interval_gran == 0, "improper PeriodicTask interval time"); } PeriodicTask::~PeriodicTask() { if (is_enrolled()) disenroll(); } bool PeriodicTask::is_enrolled() const { for(int index = 0; index < _num_tasks; index++) if (_tasks[index] == this) return true; return false; } void PeriodicTask::enroll() { assert(WatcherThread::watcher_thread() == NULL, "dynamic enrollment of tasks not yet supported"); if (_num_tasks == PeriodicTask::max_tasks) fatal("Overflow in PeriodicTask table"); _tasks[_num_tasks++] = this; } void PeriodicTask::disenroll() { assert(WatcherThread::watcher_thread() == NULL || Thread::current() == WatcherThread::watcher_thread(), "dynamic disenrollment currently only handled from WatcherThread from within task() method"); int index; for(index = 0; index < _num_tasks && _tasks[index] != this; index++); if (index == _num_tasks) return; _num_tasks--; for (; index < _num_tasks; index++) { _tasks[index] = _tasks[index+1]; } }