| /* |
| * Copyright 1997-2007 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/_gcLocker.cpp.incl" |
| |
| volatile jint GC_locker::_jni_lock_count = 0; |
| volatile jint GC_locker::_lock_count = 0; |
| volatile bool GC_locker::_needs_gc = false; |
| volatile bool GC_locker::_doing_gc = false; |
| |
| void GC_locker::stall_until_clear() { |
| assert(!JavaThread::current()->in_critical(), "Would deadlock"); |
| MutexLocker ml(JNICritical_lock); |
| // Wait for _needs_gc to be cleared |
| while (GC_locker::needs_gc()) { |
| JNICritical_lock->wait(); |
| } |
| } |
| |
| void GC_locker::jni_lock_slow() { |
| MutexLocker mu(JNICritical_lock); |
| // Block entering threads if we know at least one thread is in a |
| // JNI critical region and we need a GC. |
| // We check that at least one thread is in a critical region before |
| // blocking because blocked threads are woken up by a thread exiting |
| // a JNI critical region. |
| while ((is_jni_active() && needs_gc()) || _doing_gc) { |
| JNICritical_lock->wait(); |
| } |
| jni_lock(); |
| } |
| |
| void GC_locker::jni_unlock_slow() { |
| MutexLocker mu(JNICritical_lock); |
| jni_unlock(); |
| if (needs_gc() && !is_jni_active()) { |
| // We're the last thread out. Cause a GC to occur. |
| // GC will also check is_active, so this check is not |
| // strictly needed. It's added here to make it clear that |
| // the GC will NOT be performed if any other caller |
| // of GC_locker::lock() still needs GC locked. |
| if (!is_active()) { |
| _doing_gc = true; |
| { |
| // Must give up the lock while at a safepoint |
| MutexUnlocker munlock(JNICritical_lock); |
| Universe::heap()->collect(GCCause::_gc_locker); |
| } |
| _doing_gc = false; |
| } |
| clear_needs_gc(); |
| JNICritical_lock->notify_all(); |
| } |
| } |
| |
| // Implementation of No_GC_Verifier |
| |
| #ifdef ASSERT |
| |
| No_GC_Verifier::No_GC_Verifier(bool verifygc) { |
| _verifygc = verifygc; |
| if (_verifygc) { |
| CollectedHeap* h = Universe::heap(); |
| assert(!h->is_gc_active(), "GC active during No_GC_Verifier"); |
| _old_invocations = h->total_collections(); |
| } |
| } |
| |
| |
| No_GC_Verifier::~No_GC_Verifier() { |
| if (_verifygc) { |
| CollectedHeap* h = Universe::heap(); |
| assert(!h->is_gc_active(), "GC active during No_GC_Verifier"); |
| if (_old_invocations != h->total_collections()) { |
| fatal("collection in a No_GC_Verifier secured function"); |
| } |
| } |
| } |
| |
| Pause_No_GC_Verifier::Pause_No_GC_Verifier(No_GC_Verifier * ngcv) { |
| _ngcv = ngcv; |
| if (_ngcv->_verifygc) { |
| // if we were verifying, then make sure that nothing is |
| // wrong before we "pause" verification |
| CollectedHeap* h = Universe::heap(); |
| assert(!h->is_gc_active(), "GC active during No_GC_Verifier"); |
| if (_ngcv->_old_invocations != h->total_collections()) { |
| fatal("collection in a No_GC_Verifier secured function"); |
| } |
| } |
| } |
| |
| |
| Pause_No_GC_Verifier::~Pause_No_GC_Verifier() { |
| if (_ngcv->_verifygc) { |
| // if we were verifying before, then reenable verification |
| CollectedHeap* h = Universe::heap(); |
| assert(!h->is_gc_active(), "GC active during No_GC_Verifier"); |
| _ngcv->_old_invocations = h->total_collections(); |
| } |
| } |
| |
| |
| // JRT_LEAF rules: |
| // A JRT_LEAF method may not interfere with safepointing by |
| // 1) acquiring or blocking on a Mutex or JavaLock - checked |
| // 2) allocating heap memory - checked |
| // 3) executing a VM operation - checked |
| // 4) executing a system call (including malloc) that could block or grab a lock |
| // 5) invoking GC |
| // 6) reaching a safepoint |
| // 7) running too long |
| // Nor may any method it calls. |
| JRT_Leaf_Verifier::JRT_Leaf_Verifier() |
| : No_Safepoint_Verifier(true, JRT_Leaf_Verifier::should_verify_GC()) |
| { |
| } |
| |
| JRT_Leaf_Verifier::~JRT_Leaf_Verifier() |
| { |
| } |
| |
| bool JRT_Leaf_Verifier::should_verify_GC() { |
| switch (JavaThread::current()->thread_state()) { |
| case _thread_in_Java: |
| // is in a leaf routine, there must be no safepoint. |
| return true; |
| case _thread_in_native: |
| // A native thread is not subject to safepoints. |
| // Even while it is in a leaf routine, GC is ok |
| return false; |
| default: |
| // Leaf routines cannot be called from other contexts. |
| ShouldNotReachHere(); |
| return false; |
| } |
| } |
| #endif |