duke@435: /*
stefank@2314:  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "gc_implementation/concurrentMarkSweep/cmsLockVerifier.hpp"
stefank@2314: #include "gc_implementation/concurrentMarkSweep/concurrentMarkSweepThread.hpp"
stefank@2314: #include "runtime/vmThread.hpp"
duke@435: 
duke@435: ///////////// Locking verification specific to CMS //////////////
duke@435: // Much like "assert_lock_strong()", except that it relaxes the
duke@435: // assertion somewhat for the parallel GC case, where VM thread
duke@435: // or the CMS thread might hold the lock on behalf of the parallel
duke@435: // threads. The second argument is in support of an extra locking
duke@435: // check for CFL spaces' free list locks.
duke@435: #ifndef PRODUCT
ysr@1580: void CMSLockVerifier::assert_locked(const Mutex* lock,
ysr@1580:                                     const Mutex* p_lock1,
ysr@1580:                                     const Mutex* p_lock2) {
duke@435:   if (!Universe::is_fully_initialized()) {
duke@435:     return;
duke@435:   }
duke@435: 
duke@435:   Thread* myThread = Thread::current();
duke@435: 
duke@435:   if (lock == NULL) { // a "lock-free" structure, e.g. MUT, protected by CMS token
ysr@1580:     assert(p_lock1 == NULL && p_lock2 == NULL, "Unexpected caller error");
duke@435:     if (myThread->is_ConcurrentGC_thread()) {
duke@435:       // This test might have to change in the future, if there can be
duke@435:       // multiple peer CMS threads.  But for now, if we're testing the CMS
duke@435:       assert(myThread == ConcurrentMarkSweepThread::cmst(),
duke@435:              "In CMS, CMS thread is the only Conc GC thread.");
duke@435:       assert(ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
duke@435:              "CMS thread should have CMS token");
duke@435:     } else if (myThread->is_VM_thread()) {
duke@435:       assert(ConcurrentMarkSweepThread::vm_thread_has_cms_token(),
duke@435:              "VM thread should have CMS token");
duke@435:     } else {
duke@435:       // Token should be held on our behalf by one of the other
duke@435:       // of CMS or VM thread; not enough easily testable
duke@435:       // state info to test which here.
duke@435:       assert(myThread->is_GC_task_thread(), "Unexpected thread type");
duke@435:     }
duke@435:     return;
duke@435:   }
duke@435: 
ysr@1580:   if (myThread->is_VM_thread()
ysr@1580:       || myThread->is_ConcurrentGC_thread()
ysr@1580:       || myThread->is_Java_thread()) {
ysr@1580:     // Make sure that we are holding the associated lock.
duke@435:     assert_lock_strong(lock);
ysr@1580:     // The checking of p_lock is a spl case for CFLS' free list
ysr@1580:     // locks: we make sure that none of the parallel GC work gang
ysr@1580:     // threads are holding "sub-locks" of freeListLock(). We check only
ysr@1580:     // the parDictionaryAllocLock because the others are too numerous.
ysr@1580:     // This spl case code is somewhat ugly and any improvements
ysr@1580:     // are welcome.
ysr@1580:     assert(p_lock1 == NULL || !p_lock1->is_locked() || p_lock1->owned_by_self(),
ysr@1580:            "Possible race between this and parallel GC threads");
ysr@1580:     assert(p_lock2 == NULL || !p_lock2->is_locked() || p_lock2->owned_by_self(),
ysr@1580:            "Possible race between this and parallel GC threads");
ysr@1580:   } else if (myThread->is_GC_task_thread()) {
ysr@1580:     // Make sure that the VM or CMS thread holds lock on our behalf
ysr@1580:     // XXX If there were a concept of a gang_master for a (set of)
ysr@1580:     // gang_workers, we could have used the identity of that thread
ysr@1580:     // for checking ownership here; for now we just disjunct.
ysr@1580:     assert(lock->owner() == VMThread::vm_thread() ||
ysr@1580:            lock->owner() == ConcurrentMarkSweepThread::cmst(),
ysr@1580:            "Should be locked by VM thread or CMS thread on my behalf");
ysr@1580:     if (p_lock1 != NULL) {
ysr@1580:       assert_lock_strong(p_lock1);
ysr@1580:     }
ysr@1580:     if (p_lock2 != NULL) {
ysr@1580:       assert_lock_strong(p_lock2);
ysr@1580:     }
duke@435:   } else {
ysr@1580:     // Make sure we didn't miss some other thread type calling into here;
ysr@1580:     // perhaps as a result of future VM evolution.
ysr@1580:     ShouldNotReachHere();
duke@435:   }
duke@435: }
duke@435: #endif