1 /*
   2  * Copyright (c) 2014, 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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP
  27 
  28 #include "gc_implementation/g1/g1ParScanThreadState.hpp"
  29 #include "gc_implementation/g1/g1RemSet.inline.hpp"
  30 #include "oops/oop.inline.hpp"
  31 
  32 template <class T> inline void G1ParScanThreadState::immediate_rs_update(HeapRegion* from, T* p, int tid) {
  33   if (!from->is_survivor()) {
  34     _g1_rem->par_write_ref(from, p, tid);
  35   }
  36 }
  37 
  38 template <class T> void G1ParScanThreadState::update_rs(HeapRegion* from, T* p, int tid) {
  39   if (G1DeferredRSUpdate) {
  40     deferred_rs_update(from, p, tid);
  41   } else {
  42     immediate_rs_update(from, p, tid);
  43   }
  44 }
  45 
  46 inline void G1ParScanThreadState::do_oop_partial_array(oop* p) {
  47   assert(has_partial_array_mask(p), "invariant");
  48   oop from_obj = clear_partial_array_mask(p);
  49 
  50   assert(Universe::heap()->is_in_reserved(from_obj), "must be in heap.");
  51   assert(from_obj->is_objArray(), "must be obj array");
  52   objArrayOop from_obj_array = objArrayOop(from_obj);
  53   // The from-space object contains the real length.
  54   int length                 = from_obj_array->length();
  55 
  56   assert(from_obj->is_forwarded(), "must be forwarded");
  57   oop to_obj                 = from_obj->forwardee();
  58   assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
  59   objArrayOop to_obj_array   = objArrayOop(to_obj);
  60   // We keep track of the next start index in the length field of the
  61   // to-space object.
  62   int next_index             = to_obj_array->length();
  63   assert(0 <= next_index && next_index < length,
  64          err_msg("invariant, next index: %d, length: %d", next_index, length));
  65 
  66   int start                  = next_index;
  67   int end                    = length;
  68   int remainder              = end - start;
  69   // We'll try not to push a range that's smaller than ParGCArrayScanChunk.
  70   if (remainder > 2 * ParGCArrayScanChunk) {
  71     end = start + ParGCArrayScanChunk;
  72     to_obj_array->set_length(end);
  73     // Push the remainder before we process the range in case another
  74     // worker has run out of things to do and can steal it.
  75     oop* from_obj_p = set_partial_array_mask(from_obj);
  76     push_on_queue(from_obj_p);
  77   } else {
  78     assert(length == end, "sanity");
  79     // We'll process the final range for this object. Restore the length
  80     // so that the heap remains parsable in case of evacuation failure.
  81     to_obj_array->set_length(end);
  82   }
  83   _scanner.set_region(_g1h->heap_region_containing_raw(to_obj));
  84   // Process indexes [start,end). It will also process the header
  85   // along with the first chunk (i.e., the chunk with start == 0).
  86   // Note that at this point the length field of to_obj_array is not
  87   // correct given that we are using it to keep track of the next
  88   // start index. oop_iterate_range() (thankfully!) ignores the length
  89   // field and only relies on the start / end parameters.  It does
  90   // however return the size of the object which will be incorrect. So
  91   // we have to ignore it even if we wanted to use it.
  92   to_obj_array->oop_iterate_range(&_scanner, start, end);
  93 }
  94 
  95 template <class T> inline void G1ParScanThreadState::deal_with_reference(T* ref_to_scan) {
  96   if (!has_partial_array_mask(ref_to_scan)) {
  97     // Note: we can use "raw" versions of "region_containing" because
  98     // "obj_to_scan" is definitely in the heap, and is not in a
  99     // humongous region.
 100     HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan);
 101     do_oop_evac(ref_to_scan, r);
 102   } else {
 103     do_oop_partial_array((oop*)ref_to_scan);
 104   }
 105 }
 106 
 107 inline void G1ParScanThreadState::deal_with_reference(StarTask ref) {
 108   assert(verify_task(ref), "sanity");
 109   if (ref.is_narrow()) {
 110     deal_with_reference((narrowOop*)ref);
 111   } else {
 112     deal_with_reference((oop*)ref);
 113   }
 114 }
 115 
 116 #endif /* SHARE_VM_GC_IMPLEMENTATION_G1_G1PARSCANTHREADSTATE_INLINE_HPP */
 117