1 /*

     2  * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved.

     3  *

     4  * This code is free software; you can redistribute it and/or modify it

     5  * under the terms of the GNU General Public License version 2 only, as

     6  * published by the Free Software Foundation.

     7  *

     8  * This code is distributed in the hope that it will be useful, but WITHOUT

     9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    11  * version 2 for more details (a copy is included in the LICENSE file that

    12  * accompanied this code).

    13  *

    14  * You should have received a copy of the GNU General Public License version

    15  * 2 along with this work; if not, write to the Free Software Foundation,

    16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    17  *

    18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    19  * or visit www.oracle.com if you need additional information or have any

    20  * questions.

    21  *

    22  */

    23 

    24 #include "precompiled.hpp"

    25 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"

    26 #include "gc/shenandoah/shenandoahHeapRegionSet.inline.hpp"

    27 #include "gc/shenandoah/shenandoahHeap.hpp"

    28 #include "gc/shenandoah/shenandoahHeap.inline.hpp"

    29 #include "gc/shenandoah/shenandoahHeapRegion.hpp"

    30 #include "gc/shenandoah/shenandoahUtils.hpp"

    31 #include "runtime/atomic.hpp"

    32 #include "utilities/copy.hpp"

    33 

    34 ShenandoahHeapRegionSetIterator::ShenandoahHeapRegionSetIterator(const ShenandoahHeapRegionSet* const set) :

    35         _set(set), _heap(ShenandoahHeap::heap()), _current_index(0) {}

    36 

    37 void ShenandoahHeapRegionSetIterator::reset(const ShenandoahHeapRegionSet* const set) {

    38   _set = set;

    39   _current_index = 0;

    40 }

    41 

    42 ShenandoahHeapRegionSet::ShenandoahHeapRegionSet() :

    43   _heap(ShenandoahHeap::heap()),

    44   _map_size(_heap->num_regions()),

    45   _region_size_bytes_shift(ShenandoahHeapRegion::region_size_bytes_shift()),

    46   _set_map(NEW_C_HEAP_ARRAY(jbyte, _map_size, mtGC)),

    47   _biased_set_map(_set_map - ((uintx)_heap->base() >> _region_size_bytes_shift)),

    48   _region_count(0)

    49 {

    50   // Use 1-byte data type

    51   STATIC_ASSERT(sizeof(jbyte) == 1);

    52 

    53   // Initialize cset map

    54   Copy::zero_to_bytes(_set_map, _map_size);

    55 }

    56 

    57 ShenandoahHeapRegionSet::~ShenandoahHeapRegionSet() {

    58   FREE_C_HEAP_ARRAY(jbyte, _set_map);

    59 }

    60 

    61 void ShenandoahHeapRegionSet::add_region(ShenandoahHeapRegion* r) {

    62   assert(!is_in(r), "Already in collection set");

    63   _set_map[r->region_number()] = 1;

    64   _region_count++;

    65 }

    66 

    67 bool ShenandoahHeapRegionSet::add_region_check_for_duplicates(ShenandoahHeapRegion* r) {

    68   if (!is_in(r)) {

    69     add_region(r);

    70     return true;

    71   } else {

    72     return false;

    73   }

    74 }

    75 

    76 void ShenandoahHeapRegionSet::remove_region(ShenandoahHeapRegion* r) {

    77   assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint");

    78   assert(Thread::current()->is_VM_thread(), "Must be VMThread");

    79   assert(is_in(r), "Not in region set");

    80   _set_map[r->region_number()] = 0;

    81   _region_count --;

    82 }

    83 

    84 void ShenandoahHeapRegionSet::clear() {

    85   assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint");

    86   Copy::zero_to_bytes(_set_map, _map_size);

    87 

    88   _region_count = 0;

    89 }

    90 

    91 ShenandoahHeapRegion* ShenandoahHeapRegionSetIterator::claim_next() {

    92   size_t num_regions = _heap->num_regions();

    93   if (_current_index >= (jint)num_regions) {

    94     return NULL;

    95   }

    96 

    97   jint saved_current = _current_index;

    98   size_t index = (size_t)saved_current;

    99 

   100   while(index < num_regions) {

   101     if (_set->is_in(index)) {

   102       jint cur = Atomic::cmpxchg((jint)(index + 1), &_current_index, saved_current);

   103       assert(cur >= (jint)saved_current, "Must move forward");

   104       if (cur == saved_current) {

   105         assert(_set->is_in(index), "Invariant");

   106         return _heap->get_region(index);

   107       } else {

   108         index = (size_t)cur;

   109         saved_current = cur;

   110       }

   111     } else {

   112       index ++;

   113     }

   114   }

   115   return NULL;

   116 }

   117 

   118 ShenandoahHeapRegion* ShenandoahHeapRegionSetIterator::next() {

   119   size_t num_regions = _heap->num_regions();

   120   for (size_t index = (size_t)_current_index; index < num_regions; index ++) {

   121     if (_set->is_in(index)) {

   122       _current_index = (jint)(index + 1);

   123       return _heap->get_region(index);

   124     }

   125   }

   126 

   127   return NULL;

   128 }

   129 

   130 void ShenandoahHeapRegionSet::print_on(outputStream* out) const {

   131   out->print_cr("Region Set : " SIZE_FORMAT "", count());

   132 

   133   debug_only(size_t regions = 0;)

   134   for (size_t index = 0; index < _heap->num_regions(); index ++) {

   135     if (is_in(index)) {

   136       _heap->get_region(index)->print_on(out);

   137       debug_only(regions ++;)

   138     }

   139   }

   140   assert(regions == count(), "Must match");

   141 }