src/share/vm/gc_implementation/parNew/parOopClosures.inline.hpp

Tue, 10 May 2011 00:33:21 -0700

author
ysr
date
Tue, 10 May 2011 00:33:21 -0700
changeset 2889
fc2b798ab316
parent 2314
f95d63e2154a
child 4037
da91efe96a93
permissions
-rw-r--r--

6883834: ParNew: assert(!_g->to()->is_in_reserved(obj),"Scanning field twice?") with LargeObjects tests
Summary: Fixed process_chunk_boundaries(), used for parallel card scanning when using ParNew/CMS, so as to prevent double-scanning, or worse, non-scanning of imprecisely marked objects exceeding parallel chunk size. Made some sizing parameters for parallel card scanning diagnostic, disabled ParallelGCRetainPLAB, and elaborated and clarified some comments.
Reviewed-by: stefank, johnc

     1 /*
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    25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARNEW_PAROOPCLOSURES_INLINE_HPP
    26 #define SHARE_VM_GC_IMPLEMENTATION_PARNEW_PAROOPCLOSURES_INLINE_HPP
    28 #include "gc_implementation/parNew/parNewGeneration.hpp"
    29 #include "gc_implementation/parNew/parOopClosures.hpp"
    30 #include "memory/cardTableRS.hpp"
    32 template <class T> inline void ParScanWeakRefClosure::do_oop_work(T* p) {
    33   assert (!oopDesc::is_null(*p), "null weak reference?");
    34   oop obj = oopDesc::load_decode_heap_oop_not_null(p);
    35   // weak references are sometimes scanned twice; must check
    36   // that to-space doesn't already contain this object
    37   if ((HeapWord*)obj < _boundary && !_g->to()->is_in_reserved(obj)) {
    38     // we need to ensure that it is copied (see comment in
    39     // ParScanClosure::do_oop_work).
    40     klassOop objK = obj->klass();
    41     markOop m = obj->mark();
    42     oop new_obj;
    43     if (m->is_marked()) { // Contains forwarding pointer.
    44       new_obj = ParNewGeneration::real_forwardee(obj);
    45     } else {
    46       size_t obj_sz = obj->size_given_klass(objK->klass_part());
    47       new_obj = ((ParNewGeneration*)_g)->copy_to_survivor_space(_par_scan_state,
    48                                                                 obj, obj_sz, m);
    49     }
    50     oopDesc::encode_store_heap_oop_not_null(p, new_obj);
    51   }
    52 }
    54 inline void ParScanWeakRefClosure::do_oop_nv(oop* p)       { ParScanWeakRefClosure::do_oop_work(p); }
    55 inline void ParScanWeakRefClosure::do_oop_nv(narrowOop* p) { ParScanWeakRefClosure::do_oop_work(p); }
    57 template <class T> inline void ParScanClosure::par_do_barrier(T* p) {
    58   assert(generation()->is_in_reserved(p), "expected ref in generation");
    59   assert(!oopDesc::is_null(*p), "expected non-null object");
    60   oop obj = oopDesc::load_decode_heap_oop_not_null(p);
    61   // If p points to a younger generation, mark the card.
    62   if ((HeapWord*)obj < gen_boundary()) {
    63     rs()->write_ref_field_gc_par(p, obj);
    64   }
    65 }
    67 template <class T>
    68 inline void ParScanClosure::do_oop_work(T* p,
    69                                         bool gc_barrier,
    70                                         bool root_scan) {
    71   assert((!Universe::heap()->is_in_reserved(p) ||
    72           generation()->is_in_reserved(p))
    73          && (generation()->level() == 0 || gc_barrier),
    74          "The gen must be right, and we must be doing the barrier "
    75          "in older generations.");
    76   T heap_oop = oopDesc::load_heap_oop(p);
    77   if (!oopDesc::is_null(heap_oop)) {
    78     oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
    79     if ((HeapWord*)obj < _boundary) {
    80 #ifndef PRODUCT
    81       if (_g->to()->is_in_reserved(obj)) {
    82         tty->print_cr("Scanning field (" PTR_FORMAT ") twice?", p);
    83         GenCollectedHeap* gch =  (GenCollectedHeap*)Universe::heap();
    84         Space* sp = gch->space_containing(p);
    85         oop obj = oop(sp->block_start(p));
    86         assert((HeapWord*)obj < (HeapWord*)p, "Error");
    87         tty->print_cr("Object: " PTR_FORMAT, obj);
    88         tty->print_cr("-------");
    89         obj->print();
    90         tty->print_cr("-----");
    91         tty->print_cr("Heap:");
    92         tty->print_cr("-----");
    93         gch->print();
    94         ShouldNotReachHere();
    95       }
    96 #endif
    97       // OK, we need to ensure that it is copied.
    98       // We read the klass and mark in this order, so that we can reliably
    99       // get the size of the object: if the mark we read is not a
   100       // forwarding pointer, then the klass is valid: the klass is only
   101       // overwritten with an overflow next pointer after the object is
   102       // forwarded.
   103       klassOop objK = obj->klass();
   104       markOop m = obj->mark();
   105       oop new_obj;
   106       if (m->is_marked()) { // Contains forwarding pointer.
   107         new_obj = ParNewGeneration::real_forwardee(obj);
   108         oopDesc::encode_store_heap_oop_not_null(p, new_obj);
   109       } else {
   110         size_t obj_sz = obj->size_given_klass(objK->klass_part());
   111         new_obj = _g->copy_to_survivor_space(_par_scan_state, obj, obj_sz, m);
   112         oopDesc::encode_store_heap_oop_not_null(p, new_obj);
   113         if (root_scan) {
   114           // This may have pushed an object.  If we have a root
   115           // category with a lot of roots, can't let the queue get too
   116           // full:
   117           (void)_par_scan_state->trim_queues(10 * ParallelGCThreads);
   118         }
   119       }
   120       if (gc_barrier) {
   121         // Now call parent closure
   122         par_do_barrier(p);
   123       }
   124     }
   125   }
   126 }
   128 inline void ParScanWithBarrierClosure::do_oop_nv(oop* p)       { ParScanClosure::do_oop_work(p, true, false); }
   129 inline void ParScanWithBarrierClosure::do_oop_nv(narrowOop* p) { ParScanClosure::do_oop_work(p, true, false); }
   131 inline void ParScanWithoutBarrierClosure::do_oop_nv(oop* p)       { ParScanClosure::do_oop_work(p, false, false); }
   132 inline void ParScanWithoutBarrierClosure::do_oop_nv(narrowOop* p) { ParScanClosure::do_oop_work(p, false, false); }
   134 #endif // SHARE_VM_GC_IMPLEMENTATION_PARNEW_PAROOPCLOSURES_INLINE_HPP

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