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view src/share/vm/memory/space.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 | b9a9ed0f8eeb |
children | c49dcaf78a65 |
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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_SPACE_INLINE_HPP #define SHARE_VM_MEMORY_SPACE_INLINE_HPP #include "gc_interface/collectedHeap.hpp" #include "memory/space.hpp" #include "memory/universe.hpp" #include "runtime/safepoint.hpp" inline HeapWord* Space::block_start(const void* p) { return block_start_const(p); } inline HeapWord* OffsetTableContigSpace::allocate(size_t size) { HeapWord* res = ContiguousSpace::allocate(size); if (res != NULL) { _offsets.alloc_block(res, size); } return res; } // Because of the requirement of keeping "_offsets" up to date with the // allocations, we sequentialize these with a lock. Therefore, best if // this is used for larger LAB allocations only. inline HeapWord* OffsetTableContigSpace::par_allocate(size_t size) { MutexLocker x(&_par_alloc_lock); // This ought to be just "allocate", because of the lock above, but that // ContiguousSpace::allocate asserts that either the allocating thread // holds the heap lock or it is the VM thread and we're at a safepoint. // The best I (dld) could figure was to put a field in ContiguousSpace // meaning "locking at safepoint taken care of", and set/reset that // here. But this will do for now, especially in light of the comment // above. Perhaps in the future some lock-free manner of keeping the // coordination. HeapWord* res = ContiguousSpace::par_allocate(size); if (res != NULL) { _offsets.alloc_block(res, size); } return res; } inline HeapWord* OffsetTableContigSpace::block_start_const(const void* p) const { return _offsets.block_start(p); } #endif // SHARE_VM_MEMORY_SPACE_INLINE_HPP