Mercurial > hg > graal-jvmci-8
diff src/share/vm/memory/gcLocker.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | c0492d52d55b |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/gcLocker.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,160 @@ +/* + * 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