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view src/share/vm/memory/gcLocker.inline.hpp @ 12301:2c022e432e10
8024974: Incorrect use of GC_locker::is_active()
Summary: SymbolTable and StringTable can make calls to GC_locker::is_active() outside a safepoint. This isn't safe because the GC_locker active state (lock count) is only updated at a safepoint and only remains valid as long as _needs_gc is true. However, outside a safepoint_needs_gc can change to false at any time, which makes it impossible to do a correct call to is_active() in that context. In this case these calls can just be removed since the input argument to basic_add() should never be on the heap and so there's no need to check the GC_locker state. This change also adjusts the assert() in is_active() to makes sure all calls to this function are always done under a safepoint.
Reviewed-by: brutisso, dcubed
Contributed-by: per.liden@oracle.com
author | stefank |
---|---|
date | Fri, 20 Sep 2013 10:53:28 +0200 |
parents | ad3b47344802 |
children | 9c3dc501b5eb |
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/* * Copyright (c) 2000, 2012, 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 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_MEMORY_GCLOCKER_INLINE_HPP #define SHARE_VM_MEMORY_GCLOCKER_INLINE_HPP #include "memory/gcLocker.hpp" inline void GC_locker::lock() { // cast away volatile Atomic::inc(&_lock_count); CHECK_UNHANDLED_OOPS_ONLY( if (CheckUnhandledOops) { Thread::current()->_gc_locked_out_count++; }) assert(Universe::heap() == NULL || !Universe::heap()->is_gc_active(), "locking failed"); } inline void GC_locker::unlock() { // cast away volatile Atomic::dec(&_lock_count); CHECK_UNHANDLED_OOPS_ONLY( if (CheckUnhandledOops) { Thread::current()->_gc_locked_out_count--; }) } inline void GC_locker::lock_critical(JavaThread* thread) { if (!thread->in_critical()) { if (needs_gc()) { // jni_lock call calls enter_critical under the lock so that the // global lock count and per thread count are in agreement. jni_lock(thread); return; } increment_debug_jni_lock_count(); } thread->enter_critical(); } inline void GC_locker::unlock_critical(JavaThread* thread) { if (thread->in_last_critical()) { if (needs_gc()) { // jni_unlock call calls exit_critical under the lock so that // the global lock count and per thread count are in agreement. jni_unlock(thread); return; } decrement_debug_jni_lock_count(); } thread->exit_critical(); } #endif // SHARE_VM_MEMORY_GCLOCKER_INLINE_HPP