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

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

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

Fri, 06 Aug 2010 10:17:21 -0700

author: johnc
date: Fri, 06 Aug 2010 10:17:21 -0700
changeset 2063: a03ae377b2e8
parent 2060: 2d160770d2e5
child 2216: c32059ef4dc0
permissions: -rw-r--r--

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

 /*
  * Copyright (c) 2001, 2010, 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.
  *
  */
 inline size_t G1RemSet::n_workers() {
   if (_g1->workers() != NULL) {
     return _g1->workers()->total_workers();
   } else {
     return 1;
   }
 }
 template <class T> inline void HRInto_G1RemSet::write_ref_nv(HeapRegion* from, T* p) {
   par_write_ref_nv(from, p, 0);
 }
 inline bool HRInto_G1RemSet::self_forwarded(oop obj) {
   bool result =  (obj->is_forwarded() && (obj->forwardee()== obj));
   return result;
 }
 template <class T> inline void HRInto_G1RemSet::par_write_ref_nv(HeapRegion* from, T* p, int tid) {
   oop obj = oopDesc::load_decode_heap_oop(p);
 #ifdef ASSERT
   // can't do because of races
   // assert(obj == NULL || obj->is_oop(), "expected an oop");
   // Do the safe subset of is_oop
   if (obj != NULL) {
 #ifdef CHECK_UNHANDLED_OOPS
     oopDesc* o = obj.obj();
 #else
     oopDesc* o = obj;
 #endif // CHECK_UNHANDLED_OOPS
     assert((intptr_t)o % MinObjAlignmentInBytes == 0, "not oop aligned");
     assert(Universe::heap()->is_in_reserved(obj), "must be in heap");
   }
 #endif // ASSERT
   assert(from == NULL || from->is_in_reserved(p), "p is not in from");
   HeapRegion* to = _g1->heap_region_containing(obj);
   // The test below could be optimized by applying a bit op to to and from.
   if (to != NULL && from != NULL && from != to) {
     // The _traversal_in_progress flag is true during the collection pause,
     // false during the evacuation failure handling. This should avoid a
     // potential loop if we were to add the card containing 'p' to the DCQS
     // that's used to regenerate the remembered sets for the collection set,
     // in the event of an evacuation failure, here. The UpdateRSImmediate
     // closure will eventally call this routine.
     if (_traversal_in_progress &&
         to->in_collection_set() && !self_forwarded(obj)) {
       assert(_cset_rs_update_cl[tid] != NULL, "should have been set already");
       _cset_rs_update_cl[tid]->do_oop(p);
       // Deferred updates to the CSet are either discarded (in the normal case),
       // or processed (if an evacuation failure occurs) at the end
       // of the collection.
       // See HRInto_G1RemSet::cleanup_after_oops_into_collection_set_do().
     } else {
 #if G1_REM_SET_LOGGING
       gclog_or_tty->print_cr("Adding " PTR_FORMAT " (" PTR_FORMAT ") to RS"
                              " for region [" PTR_FORMAT ", " PTR_FORMAT ")",
                              p, obj,
                              to->bottom(), to->end());
 #endif
       assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
       to->rem_set()->add_reference(p, tid);
     }
   }
 }
 template <class T> inline void UpdateRSOopClosure::do_oop_work(T* p) {
   assert(_from != NULL, "from region must be non-NULL");
   _rs->par_write_ref(_from, p, _worker_i);
 }
 template <class T> inline void UpdateRSetImmediate::do_oop_work(T* p) {
   assert(_from->is_in_reserved(p), "paranoia");
   T heap_oop = oopDesc::load_heap_oop(p);
   if (!oopDesc::is_null(heap_oop) && !_from->is_survivor()) {
     _g1_rem_set->par_write_ref(_from, p, 0);
   }
 }

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

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