1 /* 2 * Copyright (c) 1990 University of Utah. 3 * Copyright (c) 1991 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the Systems Programming Group of the University of Utah Computer 8 * Science Department. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: @(#)swap_pager.h 7.1 (Berkeley) 12/5/90 39 * $Id: swap_pager.h,v 1.23 1999/01/21 08:29:10 dillon Exp $ 40 */ 41 42 /* 43 * Modifications to the block allocation data structure by John S. Dyson 44 * 18 Dec 93. 45 */ 46 47 #ifndef _SWAP_PAGER_ 48 #define _SWAP_PAGER_ 1 49 50 /* 51 * SWB_NPAGES can be set to any value from 1 to 16 pages per allocation, 52 * however, due to the allocation spilling into non-swap pager backed memory, 53 * suggest keeping SWB_NPAGES small (1-4). If high performance is mandatory 54 * perhaps up to 8 pages might be in order???? 55 * Above problem has been fixed, now we support 16 pages per block. Unused 56 * space is recovered by the swap pager now... 57 */ 58 #if !defined(SWB_NPAGES) 59 #define SWB_NPAGES 8 60 #endif 61 62 /* 63 * Piecemeal swap metadata structure. Swap is stored in a radix tree. 64 * 65 * If SWB_NPAGES is 8 and sizeof(char *) == sizeof(daddr_t), our radix 66 * is basically 8. Assuming PAGE_SIZE == 4096, one tree level represents 67 * 32K worth of data, two levels represent 256K, three levels represent 68 * 2 MBytes. This is acceptable. 69 * 70 * Overall memory utilization is about the same as the old swap structure. 71 */ 72 73 #define SWCORRECT(n) (sizeof(void *) * (n) / sizeof(daddr_t)) 74 75 #define SWAP_META_PAGES (SWB_NPAGES * 2) 76 #define SWAP_META_MASK (SWAP_META_PAGES - 1) 77 78 struct swblock { 79 struct swblock *swb_hnext; 80 vm_object_t swb_object; 81 int swb_index; 82 int swb_count; 83 daddr_t swb_pages[SWAP_META_PAGES]; 84 }; 85 86 #ifdef KERNEL 87 extern struct pagerlst swap_pager_un_object_list; 88 extern int swap_pager_full; 89 extern struct blist *swapblist; 90 91 void swap_pager_putpages __P((vm_object_t, vm_page_t *, int, boolean_t, int *)); 92 boolean_t swap_pager_haspage __P((vm_object_t object, vm_pindex_t pindex, int *before, int *after)); 93 94 int swap_pager_swp_alloc __P((vm_object_t, int)); 95 void swap_pager_copy __P((vm_object_t, vm_object_t, vm_pindex_t, int)); 96 void swap_pager_freespace __P((vm_object_t, vm_pindex_t, vm_size_t)); 97 void swap_pager_dmzspace __P((vm_object_t, vm_pindex_t, vm_size_t)); 98 void swap_pager_swap_init __P((void)); 99 100 /* 101 * newswap functions 102 */ 103 104 void swap_pager_page_removed __P((vm_page_t, vm_object_t)); 105 106 #endif 107 108 #endif /* _SWAP_PAGER_ */ 109