1 /*

     2  * Copyright (c) 2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 inline void ParScanWeakRefClosure::do_oop(oop* p)

    26 {

    27   oop obj = *p;

    28   assert (obj != NULL, "null weak reference?");

    29   // weak references are sometimes scanned twice; must check

    30   // that to-space doesn't already contain this object

    31   if ((HeapWord*)obj < _boundary && !_g->to()->is_in_reserved(obj)) {

    32     // we need to ensure that it is copied (see comment in

    33     // ParScanClosure::do_oop_work).

    34     klassOop objK = obj->klass();

    35     markOop m = obj->mark();

    36     if (m->is_marked()) { // Contains forwarding pointer.

    37       *p = ParNewGeneration::real_forwardee(obj);

    38     } else {

    39       size_t obj_sz = obj->size_given_klass(objK->klass_part());

    40       *p = ((ParNewGeneration*)_g)->copy_to_survivor_space(_par_scan_state,

    41                                                            obj, obj_sz, m);

    42     }

    43   }

    44 }

    45 

    46 inline void ParScanWeakRefClosure::do_oop_nv(oop* p)

    47 {

    48   ParScanWeakRefClosure::do_oop(p);

    49 }

    50 

    51 inline void ParScanClosure::par_do_barrier(oop* p) {

    52   assert(generation()->is_in_reserved(p), "expected ref in generation");

    53   oop obj = *p;

    54   assert(obj != NULL, "expected non-null object");

    55   // If p points to a younger generation, mark the card.

    56   if ((HeapWord*)obj < gen_boundary()) {

    57     rs()->write_ref_field_gc_par(p, obj);

    58   }

    59 }

    60 

    61 inline void ParScanClosure::do_oop_work(oop* p,

    62                                         bool gc_barrier,

    63                                         bool root_scan) {

    64   oop obj = *p;

    65   assert((!Universe::heap()->is_in_reserved(p) ||

    66           generation()->is_in_reserved(p))

    67          && (generation()->level() == 0 || gc_barrier),

    68          "The gen must be right, and we must be doing the barrier "

    69          "in older generations.");

    70   if (obj != NULL) {

    71     if ((HeapWord*)obj < _boundary) {

    72       assert(!_g->to()->is_in_reserved(obj), "Scanning field twice?");

    73       // OK, we need to ensure that it is copied.

    74       // We read the klass and mark in this order, so that we can reliably

    75       // get the size of the object: if the mark we read is not a

    76       // forwarding pointer, then the klass is valid: the klass is only

    77       // overwritten with an overflow next pointer after the object is

    78       // forwarded.

    79       klassOop objK = obj->klass();

    80       markOop m = obj->mark();

    81       if (m->is_marked()) { // Contains forwarding pointer.

    82         *p = ParNewGeneration::real_forwardee(obj);

    83       } else {

    84         size_t obj_sz = obj->size_given_klass(objK->klass_part());

    85         *p = _g->copy_to_survivor_space(_par_scan_state, obj, obj_sz, m);

    86         if (root_scan) {

    87           // This may have pushed an object.  If we have a root

    88           // category with a lot of roots, can't let the queue get too

    89           // full:

    90           (void)_par_scan_state->trim_queues(10 * ParallelGCThreads);

    91         }

    92       }

    93       if (gc_barrier) {

    94         // Now call parent closure

    95         par_do_barrier(p);

    96       }

    97     }

    98   }

    99 }