1 /* $OpenBSD: uvm_anon.c,v 1.50 2020/11/24 13:49:09 mpi Exp $ */ 2 /* $NetBSD: uvm_anon.c,v 1.10 2000/11/25 06:27:59 chs Exp $ */ 3 4 /* 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * uvm_anon.c: uvm anon ops 31 */ 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/malloc.h> 36 #include <sys/pool.h> 37 #include <sys/kernel.h> 38 #include <sys/atomic.h> 39 40 #include <uvm/uvm.h> 41 #include <uvm/uvm_swap.h> 42 43 struct pool uvm_anon_pool; 44 45 /* 46 * allocate anons 47 */ 48 void 49 uvm_anon_init(void) 50 { 51 pool_init(&uvm_anon_pool, sizeof(struct vm_anon), 0, IPL_NONE, 52 PR_WAITOK, "anonpl", NULL); 53 pool_sethiwat(&uvm_anon_pool, uvmexp.free / 16); 54 } 55 56 /* 57 * allocate an anon 58 */ 59 struct vm_anon * 60 uvm_analloc(void) 61 { 62 struct vm_anon *anon; 63 64 anon = pool_get(&uvm_anon_pool, PR_NOWAIT); 65 if (anon) { 66 anon->an_ref = 1; 67 anon->an_page = NULL; 68 anon->an_swslot = 0; 69 } 70 return(anon); 71 } 72 73 /* 74 * uvm_anfree: free a single anon structure 75 * 76 * => caller must remove anon from its amap before calling (if it was in 77 * an amap). 78 * => we may lock the pageq's. 79 */ 80 void 81 uvm_anfree_list(struct vm_anon *anon, struct pglist *pgl) 82 { 83 struct vm_page *pg; 84 85 /* get page */ 86 pg = anon->an_page; 87 88 /* 89 * if we have a resident page, we must dispose of it before freeing 90 * the anon. 91 */ 92 if (pg) { 93 /* 94 * if page is busy then we just mark it as released (who ever 95 * has it busy must check for this when they wake up). if the 96 * page is not busy then we can free it now. 97 */ 98 if ((pg->pg_flags & PG_BUSY) != 0) { 99 /* tell them to dump it when done */ 100 atomic_setbits_int(&pg->pg_flags, PG_RELEASED); 101 return; 102 } 103 pmap_page_protect(pg, PROT_NONE); 104 if (pgl != NULL) { 105 /* 106 * clean page, and put on on pglist 107 * for later freeing. 108 */ 109 uvm_lock_pageq(); 110 uvm_pageclean(pg); 111 uvm_unlock_pageq(); 112 TAILQ_INSERT_HEAD(pgl, pg, pageq); 113 } else { 114 uvm_lock_pageq(); /* lock out pagedaemon */ 115 uvm_pagefree(pg); /* bye bye */ 116 uvm_unlock_pageq(); /* free the daemon */ 117 } 118 } 119 if (pg == NULL && anon->an_swslot != 0) { 120 /* this page is no longer only in swap. */ 121 KASSERT(uvmexp.swpgonly > 0); 122 uvmexp.swpgonly--; 123 } 124 125 /* free any swap resources. */ 126 uvm_anon_dropswap(anon); 127 128 /* 129 * now that we've stripped the data areas from the anon, free the anon 130 * itself! 131 */ 132 KASSERT(anon->an_page == NULL); 133 KASSERT(anon->an_swslot == 0); 134 135 pool_put(&uvm_anon_pool, anon); 136 } 137 138 void 139 uvm_anfree(struct vm_anon *anon) 140 { 141 uvm_anfree_list(anon, NULL); 142 } 143 144 /* 145 * uvm_anwait: wait for memory to become available to allocate an anon. 146 */ 147 void 148 uvm_anwait(void) 149 { 150 struct vm_anon *anon; 151 152 /* XXX: Want something like pool_wait()? */ 153 anon = pool_get(&uvm_anon_pool, PR_WAITOK); 154 pool_put(&uvm_anon_pool, anon); 155 } 156 157 /* 158 * uvm_anon_dropswap: release any swap resources from this anon. 159 */ 160 void 161 uvm_anon_dropswap(struct vm_anon *anon) 162 { 163 164 if (anon->an_swslot == 0) 165 return; 166 167 uvm_swap_free(anon->an_swslot, 1); 168 anon->an_swslot = 0; 169 } 170 171 /* 172 * fetch an anon's page. 173 * 174 * => returns TRUE if pagein was aborted due to lack of memory. 175 */ 176 177 boolean_t 178 uvm_anon_pagein(struct vm_anon *anon) 179 { 180 struct vm_page *pg; 181 int rv; 182 183 rv = uvmfault_anonget(NULL, NULL, anon); 184 185 switch (rv) { 186 case VM_PAGER_OK: 187 break; 188 case VM_PAGER_ERROR: 189 case VM_PAGER_REFAULT: 190 /* 191 * nothing more to do on errors. 192 * VM_PAGER_REFAULT can only mean that the anon was freed, 193 * so again there's nothing to do. 194 */ 195 return FALSE; 196 default: 197 #ifdef DIAGNOSTIC 198 panic("anon_pagein: uvmfault_anonget -> %d", rv); 199 #else 200 return FALSE; 201 #endif 202 } 203 204 /* 205 * ok, we've got the page now. 206 * mark it as dirty, clear its swslot and un-busy it. 207 */ 208 pg = anon->an_page; 209 uvm_swap_free(anon->an_swslot, 1); 210 anon->an_swslot = 0; 211 atomic_clearbits_int(&pg->pg_flags, PG_CLEAN); 212 213 /* deactivate the page (to put it on a page queue) */ 214 pmap_clear_reference(pg); 215 pmap_page_protect(pg, PROT_NONE); 216 uvm_lock_pageq(); 217 uvm_pagedeactivate(pg); 218 uvm_unlock_pageq(); 219 220 return FALSE; 221 } 222