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  */
  24 
  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 }
  32 
  33 template <class T>
  34 inline void G1RemSet::write_ref_nv(HeapRegion* from, T* p) {
  35   par_write_ref_nv(from, p, 0);
  36 }
  37 
  38 inline bool G1RemSet::self_forwarded(oop obj) {
  39   bool result =  (obj->is_forwarded() && (obj->forwardee()== obj));
  40   return result;
  41 }
  42 
  43 template <class T>
  44 inline void G1RemSet::par_write_ref_nv(HeapRegion* from, T* p, int tid) {
  45   oop obj = oopDesc::load_decode_heap_oop(p);
  46 #ifdef ASSERT
  47   // can't do because of races
  48   // assert(obj == NULL || obj->is_oop(), "expected an oop");
  49 
  50   // Do the safe subset of is_oop
  51   if (obj != NULL) {
  52 #ifdef CHECK_UNHANDLED_OOPS
  53     oopDesc* o = obj.obj();
  54 #else
  55     oopDesc* o = obj;
  56 #endif // CHECK_UNHANDLED_OOPS
  57     assert((intptr_t)o % MinObjAlignmentInBytes == 0, "not oop aligned");
  58     assert(Universe::heap()->is_in_reserved(obj), "must be in heap");
  59   }
  60 #endif // ASSERT
  61 
  62   assert(from == NULL || from->is_in_reserved(p), "p is not in from");
  63 
  64   HeapRegion* to = _g1->heap_region_containing(obj);
  65   // The test below could be optimized by applying a bit op to to and from.
  66   if (to != NULL && from != NULL && from != to) {
  67     // The _traversal_in_progress flag is true during the collection pause,
  68     // false during the evacuation failure handling. This should avoid a
  69     // potential loop if we were to add the card containing 'p' to the DCQS
  70     // that's used to regenerate the remembered sets for the collection set,
  71     // in the event of an evacuation failure, here. The UpdateRSImmediate
  72     // closure will eventally call this routine.
  73     if (_traversal_in_progress &&
  74         to->in_collection_set() && !self_forwarded(obj)) {
  75 
  76       assert(_cset_rs_update_cl[tid] != NULL, "should have been set already");
  77       _cset_rs_update_cl[tid]->do_oop(p);
  78 
  79       // Deferred updates to the CSet are either discarded (in the normal case),
  80       // or processed (if an evacuation failure occurs) at the end
  81       // of the collection.
  82       // See G1RemSet::cleanup_after_oops_into_collection_set_do().
  83     } else {
  84 #if G1_REM_SET_LOGGING
  85       gclog_or_tty->print_cr("Adding " PTR_FORMAT " (" PTR_FORMAT ") to RS"
  86                              " for region [" PTR_FORMAT ", " PTR_FORMAT ")",
  87                              p, obj,
  88                              to->bottom(), to->end());
  89 #endif
  90       assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
  91       to->rem_set()->add_reference(p, tid);
  92     }
  93   }
  94 }
  95 
  96 template <class T>
  97 inline void UpdateRSOopClosure::do_oop_work(T* p) {
  98   assert(_from != NULL, "from region must be non-NULL");
  99   _rs->par_write_ref(_from, p, _worker_i);
 100 }
 101 
 102 template <class T>
 103 inline void UpdateRSetImmediate::do_oop_work(T* p) {
 104   assert(_from->is_in_reserved(p), "paranoia");
 105   T heap_oop = oopDesc::load_heap_oop(p);
 106   if (!oopDesc::is_null(heap_oop) && !_from->is_survivor()) {
 107     _g1_rem_set->par_write_ref(_from, p, 0);
 108   }
 109 }
 110