1 /* $OpenBSD: uvm_object.c,v 1.21 2021/10/12 18:16:51 kettenis Exp $ */ 2 3 /* 4 * Copyright (c) 2006 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Mindaugas Rasiukevicius. 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * uvm_object.c: operate with memory objects 34 * 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/mman.h> 40 #include <sys/atomic.h> 41 42 #include <uvm/uvm.h> 43 44 /* Dummy object used by some pmaps for sanity checks. */ 45 const struct uvm_pagerops pmap_pager = { 46 /* nothing */ 47 }; 48 49 /* Dummy object used by the buffer cache for sanity checks. */ 50 const struct uvm_pagerops bufcache_pager = { 51 /* nothing */ 52 }; 53 54 /* We will fetch this page count per step */ 55 #define FETCH_PAGECOUNT 16 56 57 /* 58 * uvm_obj_init: initialise a uvm object. 59 */ 60 void 61 uvm_obj_init(struct uvm_object *uobj, const struct uvm_pagerops *pgops, int refs) 62 { 63 uobj->pgops = pgops; 64 RBT_INIT(uvm_objtree, &uobj->memt); 65 uobj->uo_npages = 0; 66 uobj->uo_refs = refs; 67 } 68 69 void 70 uvm_obj_destroy(struct uvm_object *uo) 71 { 72 } 73 74 #ifndef SMALL_KERNEL 75 /* 76 * uvm_obj_wire: wire the pages of entire uobj 77 * 78 * => caller must pass page-aligned start and end values 79 * => if the caller passes in a pageq pointer, we'll return a list of 80 * wired pages. 81 */ 82 83 int 84 uvm_obj_wire(struct uvm_object *uobj, voff_t start, voff_t end, 85 struct pglist *pageq) 86 { 87 int i, npages, left, error; 88 struct vm_page *pgs[FETCH_PAGECOUNT]; 89 voff_t offset = start; 90 91 left = (end - start) >> PAGE_SHIFT; 92 93 while (left) { 94 95 npages = MIN(FETCH_PAGECOUNT, left); 96 97 /* Get the pages */ 98 memset(pgs, 0, sizeof(pgs)); 99 error = (*uobj->pgops->pgo_get)(uobj, offset, pgs, &npages, 0, 100 PROT_READ | PROT_WRITE, MADV_SEQUENTIAL, 101 PGO_ALLPAGES | PGO_SYNCIO); 102 103 if (error) 104 goto error; 105 106 for (i = 0; i < npages; i++) { 107 108 KASSERT(pgs[i] != NULL); 109 KASSERT(!(pgs[i]->pg_flags & PG_RELEASED)); 110 111 if (pgs[i]->pg_flags & PQ_AOBJ) { 112 atomic_clearbits_int(&pgs[i]->pg_flags, 113 PG_CLEAN); 114 uao_dropswap(uobj, i); 115 } 116 } 117 118 /* Wire the pages */ 119 uvm_lock_pageq(); 120 for (i = 0; i < npages; i++) { 121 uvm_pagewire(pgs[i]); 122 if (pageq != NULL) 123 TAILQ_INSERT_TAIL(pageq, pgs[i], pageq); 124 } 125 uvm_unlock_pageq(); 126 127 /* Unbusy the pages */ 128 uvm_page_unbusy(pgs, npages); 129 130 left -= npages; 131 offset += (voff_t)npages << PAGE_SHIFT; 132 } 133 134 return 0; 135 136 error: 137 /* Unwire the pages which have been wired */ 138 uvm_obj_unwire(uobj, start, offset); 139 140 return error; 141 } 142 143 /* 144 * uobj_unwirepages: unwire the pages of entire uobj 145 * 146 * => caller must pass page-aligned start and end values 147 */ 148 149 void 150 uvm_obj_unwire(struct uvm_object *uobj, voff_t start, voff_t end) 151 { 152 struct vm_page *pg; 153 off_t offset; 154 155 uvm_lock_pageq(); 156 for (offset = start; offset < end; offset += PAGE_SIZE) { 157 pg = uvm_pagelookup(uobj, offset); 158 159 KASSERT(pg != NULL); 160 KASSERT(!(pg->pg_flags & PG_RELEASED)); 161 162 uvm_pageunwire(pg); 163 } 164 uvm_unlock_pageq(); 165 } 166 #endif /* !SMALL_KERNEL */ 167 168 /* 169 * uvm_obj_free: free all pages in a uvm object, used by the buffer 170 * cache to free all pages attached to a buffer. 171 */ 172 void 173 uvm_obj_free(struct uvm_object *uobj) 174 { 175 struct vm_page *pg; 176 struct pglist pgl; 177 178 KASSERT(UVM_OBJ_IS_BUFCACHE(uobj)); 179 KERNEL_ASSERT_LOCKED(); 180 181 TAILQ_INIT(&pgl); 182 /* 183 * Extract from rb tree in offset order. The phys addresses 184 * usually increase in that order, which is better for 185 * uvm_pmr_freepageq. 186 */ 187 RBT_FOREACH(pg, uvm_objtree, &uobj->memt) { 188 /* 189 * clear PG_TABLED so we don't do work to remove 190 * this pg from the uobj we are throwing away 191 */ 192 atomic_clearbits_int(&pg->pg_flags, PG_TABLED); 193 uvm_lock_pageq(); 194 uvm_pageclean(pg); 195 uvm_unlock_pageq(); 196 TAILQ_INSERT_TAIL(&pgl, pg, pageq); 197 } 198 uvm_pmr_freepageq(&pgl); 199 } 200 201