Thu, 07 Apr 2011 09:53:20 -0700
7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes
ysr@777 | 1 | /* |
stefank@2314 | 2 | * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved. |
ysr@777 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
ysr@777 | 4 | * |
ysr@777 | 5 | * This code is free software; you can redistribute it and/or modify it |
ysr@777 | 6 | * under the terms of the GNU General Public License version 2 only, as |
ysr@777 | 7 | * published by the Free Software Foundation. |
ysr@777 | 8 | * |
ysr@777 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
ysr@777 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
ysr@777 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
ysr@777 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
ysr@777 | 13 | * accompanied this code). |
ysr@777 | 14 | * |
ysr@777 | 15 | * You should have received a copy of the GNU General Public License version |
ysr@777 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
ysr@777 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
ysr@777 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
ysr@777 | 22 | * |
ysr@777 | 23 | */ |
ysr@777 | 24 | |
stefank@2314 | 25 | #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP |
stefank@2314 | 26 | #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP |
stefank@2314 | 27 | |
ysr@777 | 28 | inline HeapWord* G1OffsetTableContigSpace::allocate(size_t size) { |
ysr@777 | 29 | HeapWord* res = ContiguousSpace::allocate(size); |
ysr@777 | 30 | if (res != NULL) { |
ysr@777 | 31 | _offsets.alloc_block(res, size); |
ysr@777 | 32 | } |
ysr@777 | 33 | return res; |
ysr@777 | 34 | } |
ysr@777 | 35 | |
ysr@777 | 36 | // Because of the requirement of keeping "_offsets" up to date with the |
ysr@777 | 37 | // allocations, we sequentialize these with a lock. Therefore, best if |
ysr@777 | 38 | // this is used for larger LAB allocations only. |
ysr@777 | 39 | inline HeapWord* G1OffsetTableContigSpace::par_allocate(size_t size) { |
ysr@777 | 40 | MutexLocker x(&_par_alloc_lock); |
tonyp@2715 | 41 | // Given that we take the lock no need to use par_allocate() here. |
tonyp@2715 | 42 | HeapWord* res = ContiguousSpace::allocate(size); |
ysr@777 | 43 | if (res != NULL) { |
ysr@777 | 44 | _offsets.alloc_block(res, size); |
ysr@777 | 45 | } |
ysr@777 | 46 | return res; |
ysr@777 | 47 | } |
ysr@777 | 48 | |
ysr@777 | 49 | inline HeapWord* G1OffsetTableContigSpace::block_start(const void* p) { |
ysr@777 | 50 | return _offsets.block_start(p); |
ysr@777 | 51 | } |
ysr@777 | 52 | |
ysr@777 | 53 | inline HeapWord* |
ysr@777 | 54 | G1OffsetTableContigSpace::block_start_const(const void* p) const { |
ysr@777 | 55 | return _offsets.block_start_const(p); |
ysr@777 | 56 | } |
stefank@2314 | 57 | |
stefank@2314 | 58 | #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP |