1 /*

     2  * Copyright (c) 2019, 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 #include "precompiled.hpp"

    26 #include "gc/g1/collectionSetChooser.hpp"

    27 #include "gc/g1/g1CollectionSetCandidates.hpp"

    28 #include "gc/g1/heapRegion.inline.hpp"

    29 

    30 HeapRegion* G1CollectionSetCandidates::pop_front() {

    31   assert(_front_idx < _num_regions, "pre-condition");

    32   HeapRegion* hr = _regions[_front_idx];

    33   assert(hr != NULL, "pre-condition");

    34   _regions[_front_idx] = NULL;

    35   assert(hr->reclaimable_bytes() <= _remaining_reclaimable_bytes,

    36          "Remaining reclaimable bytes inconsistent "

    37          "from region: " SIZE_FORMAT " remaining: " SIZE_FORMAT,

    38          hr->reclaimable_bytes(), _remaining_reclaimable_bytes);

    39   _remaining_reclaimable_bytes -= hr->reclaimable_bytes();

    40   _front_idx++;

    41   return hr;

    42 }

    43 

    44 void G1CollectionSetCandidates::push_front(HeapRegion* hr) {

    45   assert(hr != NULL, "Can't put back a NULL region");

    46   assert(_front_idx >= 1, "Too many regions have been put back.");

    47   _front_idx--;

    48   _regions[_front_idx] = hr;

    49   _remaining_reclaimable_bytes += hr->reclaimable_bytes();

    50 }

    51 

    52 void G1CollectionSetCandidates::iterate(HeapRegionClosure* cl) {

    53   for (uint i = _front_idx; i < _num_regions; i++) {

    54     HeapRegion* r = _regions[i];

    55     if (cl->do_heap_region(r)) {

    56       cl->set_incomplete();

    57       break;

    58     }

    59   }

    60 }

    61 

    62 #ifndef PRODUCT

    63 void G1CollectionSetCandidates::verify() const {

    64   guarantee(_front_idx <= _num_regions, "Index: %u Num_regions: %u", _front_idx, _num_regions);

    65   uint idx = 0;

    66   size_t sum_of_reclaimable_bytes = 0;

    67   while (idx < _front_idx) {

    68     guarantee(_regions[idx] == NULL, "All entries before _front_idx %u should be NULL, but %u is not",

    69               _front_idx, idx);

    70     idx++;

    71   }

    72   HeapRegion *prev = NULL;

    73   for (; idx < _num_regions; idx++) {

    74     HeapRegion *cur = _regions[idx];

    75     guarantee(cur != NULL, "Regions after _front_idx %u cannot be NULL but %u is", _front_idx, idx);

    76     guarantee(CollectionSetChooser::should_add(cur), "Region %u should be eligible for addition.", cur->hrm_index());

    77     if (prev != NULL) {

    78       guarantee(prev->gc_efficiency() >= cur->gc_efficiency(),

    79                 "GC efficiency for region %u: %1.4f smaller than for region %u: %1.4f",

    80                 prev->hrm_index(), prev->gc_efficiency(), cur->hrm_index(), cur->gc_efficiency());

    81     }

    82     sum_of_reclaimable_bytes += cur->reclaimable_bytes();

    83     prev = cur;

    84   }

    85   guarantee(sum_of_reclaimable_bytes == _remaining_reclaimable_bytes,

    86             "Inconsistent remaining_reclaimable bytes, remaining " SIZE_FORMAT " calculated " SIZE_FORMAT,

    87             _remaining_reclaimable_bytes, sum_of_reclaimable_bytes);

    88 }

    89 #endif // !PRODUCT