1 /* $OpenBSD: uvm_object.c,v 1.20 2021/09/05 11:44:46 mpi 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 #ifndef SMALL_KERNEL 70 /* 71 * uvm_obj_wire: wire the pages of entire uobj 72 * 73 * => caller must pass page-aligned start and end values 74 * => if the caller passes in a pageq pointer, we'll return a list of 75 * wired pages. 76 */ 77 78 int 79 uvm_obj_wire(struct uvm_object *uobj, voff_t start, voff_t end, 80 struct pglist *pageq) 81 { 82 int i, npages, left, error; 83 struct vm_page *pgs[FETCH_PAGECOUNT]; 84 voff_t offset = start; 85 86 left = (end - start) >> PAGE_SHIFT; 87 88 while (left) { 89 90 npages = MIN(FETCH_PAGECOUNT, left); 91 92 /* Get the pages */ 93 memset(pgs, 0, sizeof(pgs)); 94 error = (*uobj->pgops->pgo_get)(uobj, offset, pgs, &npages, 0, 95 PROT_READ | PROT_WRITE, MADV_SEQUENTIAL, 96 PGO_ALLPAGES | PGO_SYNCIO); 97 98 if (error) 99 goto error; 100 101 for (i = 0; i < npages; i++) { 102 103 KASSERT(pgs[i] != NULL); 104 KASSERT(!(pgs[i]->pg_flags & PG_RELEASED)); 105 106 if (pgs[i]->pg_flags & PQ_AOBJ) { 107 atomic_clearbits_int(&pgs[i]->pg_flags, 108 PG_CLEAN); 109 uao_dropswap(uobj, i); 110 } 111 } 112 113 /* Wire the pages */ 114 uvm_lock_pageq(); 115 for (i = 0; i < npages; i++) { 116 uvm_pagewire(pgs[i]); 117 if (pageq != NULL) 118 TAILQ_INSERT_TAIL(pageq, pgs[i], pageq); 119 } 120 uvm_unlock_pageq(); 121 122 /* Unbusy the pages */ 123 uvm_page_unbusy(pgs, npages); 124 125 left -= npages; 126 offset += (voff_t)npages << PAGE_SHIFT; 127 } 128 129 return 0; 130 131 error: 132 /* Unwire the pages which have been wired */ 133 uvm_obj_unwire(uobj, start, offset); 134 135 return error; 136 } 137 138 /* 139 * uobj_unwirepages: unwire the pages of entire uobj 140 * 141 * => caller must pass page-aligned start and end values 142 */ 143 144 void 145 uvm_obj_unwire(struct uvm_object *uobj, voff_t start, voff_t end) 146 { 147 struct vm_page *pg; 148 off_t offset; 149 150 uvm_lock_pageq(); 151 for (offset = start; offset < end; offset += PAGE_SIZE) { 152 pg = uvm_pagelookup(uobj, offset); 153 154 KASSERT(pg != NULL); 155 KASSERT(!(pg->pg_flags & PG_RELEASED)); 156 157 uvm_pageunwire(pg); 158 } 159 uvm_unlock_pageq(); 160 } 161 #endif /* !SMALL_KERNEL */ 162 163 /* 164 * uvm_obj_free: free all pages in a uvm object, used by the buffer 165 * cache to free all pages attached to a buffer. 166 */ 167 void 168 uvm_obj_free(struct uvm_object *uobj) 169 { 170 struct vm_page *pg; 171 struct pglist pgl; 172 173 KASSERT(UVM_OBJ_IS_BUFCACHE(uobj)); 174 KERNEL_ASSERT_LOCKED(); 175 176 TAILQ_INIT(&pgl); 177 /* 178 * Extract from rb tree in offset order. The phys addresses 179 * usually increase in that order, which is better for 180 * uvm_pmr_freepageq. 181 */ 182 RBT_FOREACH(pg, uvm_objtree, &uobj->memt) { 183 /* 184 * clear PG_TABLED so we don't do work to remove 185 * this pg from the uobj we are throwing away 186 */ 187 atomic_clearbits_int(&pg->pg_flags, PG_TABLED); 188 uvm_lock_pageq(); 189 uvm_pageclean(pg); 190 uvm_unlock_pageq(); 191 TAILQ_INSERT_TAIL(&pgl, pg, pageq); 192 } 193 uvm_pmr_freepageq(&pgl); 194 } 195 196