| paul@93 | 1 | /* |
| paul@93 | 2 | * A page queue retaining two internal collections of memory pages. |
| paul@93 | 3 | * |
| paul@93 | 4 | * Copyright (C) 2021 Paul Boddie <paul@boddie.org.uk> |
| paul@93 | 5 | * |
| paul@93 | 6 | * This program is free software; you can redistribute it and/or |
| paul@93 | 7 | * modify it under the terms of the GNU General Public License as |
| paul@93 | 8 | * published by the Free Software Foundation; either version 2 of |
| paul@93 | 9 | * the License, or (at your option) any later version. |
| paul@93 | 10 | * |
| paul@93 | 11 | * This program is distributed in the hope that it will be useful, |
| paul@93 | 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| paul@93 | 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| paul@93 | 14 | * GNU General Public License for more details. |
| paul@93 | 15 | * |
| paul@93 | 16 | * You should have received a copy of the GNU General Public License |
| paul@93 | 17 | * along with this program; if not, write to the Free Software |
| paul@93 | 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| paul@93 | 19 | * Boston, MA 02110-1301, USA |
| paul@93 | 20 | */ |
| paul@93 | 21 | |
| paul@70 | 22 | #include "page_queue_partitioned.h" |
| paul@70 | 23 | |
| paul@74 | 24 | |
| paul@74 | 25 | |
| paul@74 | 26 | /* Discard all queued flexpages. */ |
| paul@74 | 27 | |
| paul@74 | 28 | void PageQueuePartitioned::close(Memory *memory) |
| paul@74 | 29 | { |
| paul@74 | 30 | discard(_available, memory); |
| paul@74 | 31 | discard(_issued, memory); |
| paul@74 | 32 | } |
| paul@74 | 33 | |
| paul@70 | 34 | /* Keep waiting for a potential queue non-empty condition. |
| paul@70 | 35 | Then, attempt to pop an entry from the queue. */ |
| paul@70 | 36 | |
| paul@70 | 37 | void PageQueuePartitioned::pop(PageOwner **owner, Flexpage **flexpage) |
| paul@70 | 38 | { |
| paul@70 | 39 | std::unique_lock<std::mutex> guard(_lock); |
| paul@70 | 40 | QueueEntry entry; |
| paul@70 | 41 | |
| paul@70 | 42 | while (1) |
| paul@70 | 43 | { |
| paul@70 | 44 | if (_pop(&entry)) |
| paul@70 | 45 | { |
| paul@70 | 46 | *owner = entry.owner; |
| paul@70 | 47 | *flexpage = entry.flexpage; |
| paul@70 | 48 | return; |
| paul@70 | 49 | } |
| paul@70 | 50 | else |
| paul@70 | 51 | _counter.wait(guard); |
| paul@70 | 52 | } |
| paul@70 | 53 | } |
| paul@70 | 54 | |
| paul@70 | 55 | /* Check the available pages queue for entries, returning false if no entries |
| paul@70 | 56 | are available, returning true and providing the details if an entry can be |
| paul@70 | 57 | removed from the front of the queue. */ |
| paul@70 | 58 | |
| paul@70 | 59 | bool PageQueuePartitioned::_pop(QueueEntry *entry) |
| paul@70 | 60 | { |
| paul@70 | 61 | if (_available.empty()) |
| paul@70 | 62 | return false; |
| paul@70 | 63 | |
| paul@70 | 64 | *entry = _available.front(); |
| paul@70 | 65 | _available.pop_front(); |
| paul@70 | 66 | |
| paul@70 | 67 | return true; |
| paul@70 | 68 | } |
| paul@70 | 69 | |
| paul@70 | 70 | /* Push an entry for the given owner and flexpage to the appropriate queue. */ |
| paul@70 | 71 | |
| paul@70 | 72 | void PageQueuePartitioned::push(PageOwner *owner, Flexpage *flexpage) |
| paul@70 | 73 | { |
| paul@70 | 74 | std::lock_guard<std::mutex> guard(_lock); |
| paul@70 | 75 | |
| paul@70 | 76 | /* Record the entry and a position reference for the flexpage. */ |
| paul@70 | 77 | |
| paul@70 | 78 | Queue *queue; |
| paul@70 | 79 | Positions *positions = NULL; |
| paul@70 | 80 | |
| paul@70 | 81 | if (owner == NULL) |
| paul@70 | 82 | queue = &_available; |
| paul@70 | 83 | else |
| paul@70 | 84 | { |
| paul@70 | 85 | queue = &_issued; |
| paul@70 | 86 | positions = &_positions; |
| paul@70 | 87 | } |
| paul@70 | 88 | |
| paul@70 | 89 | queue->push_back((QueueEntry) {flexpage, owner}); |
| paul@70 | 90 | |
| paul@70 | 91 | if (positions != NULL) |
| paul@70 | 92 | { |
| paul@70 | 93 | Queue::iterator last = queue->end(); |
| paul@70 | 94 | last--; |
| paul@70 | 95 | positions->insert(Position(flexpage, last)); |
| paul@70 | 96 | } |
| paul@70 | 97 | |
| paul@70 | 98 | _counter.notify_one(); |
| paul@70 | 99 | } |
| paul@70 | 100 | |
| paul@70 | 101 | /* Push an entry to the front of the appropriate queue. */ |
| paul@70 | 102 | |
| paul@70 | 103 | void PageQueuePartitioned::push_front(PageOwner *owner, Flexpage *flexpage) |
| paul@70 | 104 | { |
| paul@70 | 105 | std::lock_guard<std::mutex> guard(_lock); |
| paul@70 | 106 | |
| paul@70 | 107 | Queue *queue; |
| paul@70 | 108 | Positions *positions = NULL; |
| paul@70 | 109 | |
| paul@70 | 110 | if (owner == NULL) |
| paul@70 | 111 | queue = &_available; |
| paul@70 | 112 | else |
| paul@70 | 113 | { |
| paul@70 | 114 | queue = &_issued; |
| paul@70 | 115 | positions = &_positions; |
| paul@70 | 116 | } |
| paul@70 | 117 | |
| paul@70 | 118 | queue->push_back((QueueEntry) {flexpage, owner}); |
| paul@70 | 119 | |
| paul@70 | 120 | if (positions != NULL) |
| paul@70 | 121 | positions->insert(Position(flexpage, queue->begin())); |
| paul@70 | 122 | |
| paul@70 | 123 | _counter.notify_one(); |
| paul@70 | 124 | } |
| paul@70 | 125 | |
| paul@70 | 126 | /* Remove an entry for the given owner and flexpage from the queue. */ |
| paul@70 | 127 | |
| paul@70 | 128 | bool PageQueuePartitioned::remove(PageOwner *owner, Flexpage *flexpage) |
| paul@70 | 129 | { |
| paul@74 | 130 | return PageQueue::remove(_issued, _positions, owner, flexpage); |
| paul@70 | 131 | } |
| paul@70 | 132 | |
| paul@70 | 133 | // vim: tabstop=4 expandtab shiftwidth=4 |
