1 /* 2 * A page queue abstraction. 3 * 4 * Copyright (C) 2021, 2024 Paul Boddie <paul@boddie.org.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation; either version 2 of 9 * the License, or (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, 19 * Boston, MA 02110-1301, USA 20 */ 21 22 #include "page_queue.h" 23 24 25 26 PageQueue::~PageQueue() 27 { 28 } 29 30 31 32 /* Utility methods to be used within critical sections. */ 33 34 void PageQueue::discard(Queue &queue, Memory *memory) 35 { 36 while (!queue.empty()) 37 { 38 Flexpage *flexpage = queue.front().flexpage; 39 40 queue.pop_front(); 41 memory->release(flexpage->region); 42 delete flexpage; 43 } 44 } 45 46 bool PageQueue::remove(Queue &queue, Positions &positions, PageOwner *owner, Flexpage *flexpage) 47 { 48 Positions::iterator position = positions.find(flexpage); 49 50 if (position == positions.end()) 51 return false; 52 53 /* The found owner may be different from the requesting owner or even NULL 54 if another owner has acquired and then purged its pages. Such a purged 55 flexpage is not immediately usable, however. */ 56 57 Queue::iterator entry = position->second; 58 59 if ((entry->owner == NULL) || (entry->owner != owner)) 60 return false; 61 62 queue.erase(entry); 63 positions.erase(position); 64 65 return true; 66 } 67 68 // vim: tabstop=4 expandtab shiftwidth=4