jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1RemSet.inline.hpp@a03ae377b2e8

6930581: G1: assert(ParallelGCThreads > 1 || n_yielded() == _hrrs->occupied(),"Should have yielded all the ..
Summary: During RSet updating, when ParallelGCThreads is zero, references that point into the collection set are added directly the referenced region's RSet. This can cause the sparse table in the RSet to expand. RSet scanning and the "occupied" routine will then operate on different instances of the sparse table causing the assert to trip. This may also cause some cards added post expansion to be missed during RSet scanning. When ParallelGCThreads is non-zero such references are recorded on the "references to be scanned" queue and the card containing the reference is recorded in a dirty card queue for use in the event of an evacuation failure. Employ the parallel code in the serial case to avoid expanding the RSets of regions in the collection set.
Reviewed-by: iveresov, ysr, tonyp

     1 /*

     2  * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    25 inline size_t G1RemSet::n_workers() {

    26   if (_g1->workers() != NULL) {

    27     return _g1->workers()->total_workers();

    28   } else {

    29     return 1;

    30   }

    31 }

    33 template <class T> inline void HRInto_G1RemSet::write_ref_nv(HeapRegion* from, T* p) {

    34   par_write_ref_nv(from, p, 0);

    35 }

    37 inline bool HRInto_G1RemSet::self_forwarded(oop obj) {

    38   bool result =  (obj->is_forwarded() && (obj->forwardee()== obj));

    39   return result;

    40 }

    42 template <class T> inline void HRInto_G1RemSet::par_write_ref_nv(HeapRegion* from, T* p, int tid) {

    43   oop obj = oopDesc::load_decode_heap_oop(p);

    44 #ifdef ASSERT

    45   // can't do because of races

    46   // assert(obj == NULL || obj->is_oop(), "expected an oop");

    48   // Do the safe subset of is_oop

    49   if (obj != NULL) {

    50 #ifdef CHECK_UNHANDLED_OOPS

    51     oopDesc* o = obj.obj();

    52 #else

    53     oopDesc* o = obj;

    54 #endif // CHECK_UNHANDLED_OOPS

    55     assert((intptr_t)o % MinObjAlignmentInBytes == 0, "not oop aligned");

    56     assert(Universe::heap()->is_in_reserved(obj), "must be in heap");

    57   }

    58 #endif // ASSERT

    60   assert(from == NULL || from->is_in_reserved(p), "p is not in from");

    62   HeapRegion* to = _g1->heap_region_containing(obj);

    63   // The test below could be optimized by applying a bit op to to and from.

    64   if (to != NULL && from != NULL && from != to) {

    65     // The _traversal_in_progress flag is true during the collection pause,

    66     // false during the evacuation failure handling. This should avoid a

    67     // potential loop if we were to add the card containing 'p' to the DCQS

    68     // that's used to regenerate the remembered sets for the collection set,

    69     // in the event of an evacuation failure, here. The UpdateRSImmediate

    70     // closure will eventally call this routine.

    71     if (_traversal_in_progress &&

    72         to->in_collection_set() && !self_forwarded(obj)) {

    74       assert(_cset_rs_update_cl[tid] != NULL, "should have been set already");

    75       _cset_rs_update_cl[tid]->do_oop(p);

    77       // Deferred updates to the CSet are either discarded (in the normal case),

    78       // or processed (if an evacuation failure occurs) at the end

    79       // of the collection.

    80       // See HRInto_G1RemSet::cleanup_after_oops_into_collection_set_do().

    81     } else {

    82 #if G1_REM_SET_LOGGING

    83       gclog_or_tty->print_cr("Adding " PTR_FORMAT " (" PTR_FORMAT ") to RS"

    84                              " for region [" PTR_FORMAT ", " PTR_FORMAT ")",

    85                              p, obj,

    86                              to->bottom(), to->end());

    87 #endif

    88       assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");

    89       to->rem_set()->add_reference(p, tid);

    90     }

    91   }

    92 }

    94 template <class T> inline void UpdateRSOopClosure::do_oop_work(T* p) {

    95   assert(_from != NULL, "from region must be non-NULL");

    96   _rs->par_write_ref(_from, p, _worker_i);

    97 }

    99 template <class T> inline void UpdateRSetImmediate::do_oop_work(T* p) {

   100   assert(_from->is_in_reserved(p), "paranoia");

   101   T heap_oop = oopDesc::load_heap_oop(p);

   102   if (!oopDesc::is_null(heap_oop) && !_from->is_survivor()) {

   103     _g1_rem_set->par_write_ref(_from, p, 0);

   104   }

   105 }

Mercurial > jdk8-mips64-public > hotspot / file revision

src/share/vm/gc_implementation/g1/g1RemSet.inline.hpp@a03ae377b2e8

src/share/vm/gc_implementation/g1/g1RemSet.inline.hpp