src/share/vm/gc_implementation/g1/g1OopClosures.inline.hpp

Thu, 22 Sep 2011 10:57:37 -0700

author
johnc
date
Thu, 22 Sep 2011 10:57:37 -0700
changeset 3175
4dfb2df418f2
parent 2968
842b840e67db
child 3322
4406629aa157
permissions
-rw-r--r--

6484982: G1: process references during evacuation pauses
Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate.
Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp

     1 /*
     2  * Copyright (c) 2001, 2011, 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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_INLINE_HPP
    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_INLINE_HPP
    28 #include "gc_implementation/g1/concurrentMark.inline.hpp"
    29 #include "gc_implementation/g1/g1CollectedHeap.hpp"
    30 #include "gc_implementation/g1/g1OopClosures.hpp"
    31 #include "gc_implementation/g1/g1RemSet.hpp"
    33 /*
    34  * This really ought to be an inline function, but apparently the C++
    35  * compiler sometimes sees fit to ignore inline declarations.  Sigh.
    36  */
    38 // This must a ifdef'ed because the counting it controls is in a
    39 // perf-critical inner loop.
    40 #define FILTERINTOCSCLOSURE_DOHISTOGRAMCOUNT 0
    42 template <class T> inline void FilterIntoCSClosure::do_oop_nv(T* p) {
    43   T heap_oop = oopDesc::load_heap_oop(p);
    44   if (!oopDesc::is_null(heap_oop) &&
    45       _g1->obj_in_cs(oopDesc::decode_heap_oop_not_null(heap_oop))) {
    46     _oc->do_oop(p);
    47 #if FILTERINTOCSCLOSURE_DOHISTOGRAMCOUNT
    48     if (_dcto_cl != NULL)
    49       _dcto_cl->incr_count();
    50 #endif
    51   }
    52 }
    54 #define FILTEROUTOFREGIONCLOSURE_DOHISTOGRAMCOUNT 0
    56 template <class T> inline void FilterOutOfRegionClosure::do_oop_nv(T* p) {
    57   T heap_oop = oopDesc::load_heap_oop(p);
    58   if (!oopDesc::is_null(heap_oop)) {
    59     HeapWord* obj_hw = (HeapWord*)oopDesc::decode_heap_oop_not_null(heap_oop);
    60     if (obj_hw < _r_bottom || obj_hw >= _r_end) {
    61       _oc->do_oop(p);
    62 #if FILTEROUTOFREGIONCLOSURE_DOHISTOGRAMCOUNT
    63       _out_of_region++;
    64 #endif
    65     }
    66   }
    67 }
    69 // This closure is applied to the fields of the objects that have just been copied.
    70 template <class T> inline void G1ParScanClosure::do_oop_nv(T* p) {
    71   T heap_oop = oopDesc::load_heap_oop(p);
    73   if (!oopDesc::is_null(heap_oop)) {
    74     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
    75     if (_g1->in_cset_fast_test(obj)) {
    76       // We're not going to even bother checking whether the object is
    77       // already forwarded or not, as this usually causes an immediate
    78       // stall. We'll try to prefetch the object (for write, given that
    79       // we might need to install the forwarding reference) and we'll
    80       // get back to it when pop it from the queue
    81       Prefetch::write(obj->mark_addr(), 0);
    82       Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
    84       // slightly paranoid test; I'm trying to catch potential
    85       // problems before we go into push_on_queue to know where the
    86       // problem is coming from
    87       assert(obj == oopDesc::load_decode_heap_oop(p),
    88              "p should still be pointing to obj");
    89       _par_scan_state->push_on_queue(p);
    90     } else {
    91       _par_scan_state->update_rs(_from, p, _par_scan_state->queue_num());
    92     }
    93   }
    94 }
    96 template <class T> inline void G1ParPushHeapRSClosure::do_oop_nv(T* p) {
    97   T heap_oop = oopDesc::load_heap_oop(p);
    99   if (!oopDesc::is_null(heap_oop)) {
   100     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
   101     if (_g1->in_cset_fast_test(obj)) {
   102       Prefetch::write(obj->mark_addr(), 0);
   103       Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
   105       // Place on the references queue
   106       _par_scan_state->push_on_queue(p);
   107     }
   108   }
   109 }
   111 template <class T> inline void G1CMOopClosure::do_oop_nv(T* p) {
   112   assert(_g1h->is_in_g1_reserved((HeapWord*) p), "invariant");
   113   assert(!_g1h->is_on_master_free_list(
   114                     _g1h->heap_region_containing((HeapWord*) p)), "invariant");
   116   oop obj = oopDesc::load_decode_heap_oop(p);
   117   if (_cm->verbose_high()) {
   118     gclog_or_tty->print_cr("[%d] we're looking at location "
   119                            "*"PTR_FORMAT" = "PTR_FORMAT,
   120                            _task->task_id(), p, (void*) obj);
   121   }
   122   _task->deal_with_reference(obj);
   123 }
   125 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1OOPCLOSURES_INLINE_HPP

mercurial