1 /* $OpenBSD: uvm_anon.c,v 1.49 2020/01/04 16:17:29 beck 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_pageclean(pg); 110 TAILQ_INSERT_HEAD(pgl, pg, pageq); 111 } else { 112 uvm_lock_pageq(); /* lock out pagedaemon */ 113 uvm_pagefree(pg); /* bye bye */ 114 uvm_unlock_pageq(); /* free the daemon */ 115 } 116 } 117 if (pg == NULL && anon->an_swslot != 0) { 118 /* this page is no longer only in swap. */ 119 KASSERT(uvmexp.swpgonly > 0); 120 uvmexp.swpgonly--; 121 } 122 123 /* free any swap resources. */ 124 uvm_anon_dropswap(anon); 125 126 /* 127 * now that we've stripped the data areas from the anon, free the anon 128 * itself! 129 */ 130 KASSERT(anon->an_page == NULL); 131 KASSERT(anon->an_swslot == 0); 132 133 pool_put(&uvm_anon_pool, anon); 134 } 135 136 void 137 uvm_anfree(struct vm_anon *anon) 138 { 139 uvm_anfree_list(anon, NULL); 140 } 141 142 /* 143 * uvm_anwait: wait for memory to become available to allocate an anon. 144 */ 145 void 146 uvm_anwait(void) 147 { 148 struct vm_anon *anon; 149 150 /* XXX: Want something like pool_wait()? */ 151 anon = pool_get(&uvm_anon_pool, PR_WAITOK); 152 pool_put(&uvm_anon_pool, anon); 153 } 154 155 /* 156 * uvm_anon_dropswap: release any swap resources from this anon. 157 */ 158 void 159 uvm_anon_dropswap(struct vm_anon *anon) 160 { 161 162 if (anon->an_swslot == 0) 163 return; 164 165 uvm_swap_free(anon->an_swslot, 1); 166 anon->an_swslot = 0; 167 } 168 169 /* 170 * fetch an anon's page. 171 * 172 * => returns TRUE if pagein was aborted due to lack of memory. 173 */ 174 175 boolean_t 176 uvm_anon_pagein(struct vm_anon *anon) 177 { 178 struct vm_page *pg; 179 int rv; 180 181 rv = uvmfault_anonget(NULL, NULL, anon); 182 183 switch (rv) { 184 case VM_PAGER_OK: 185 break; 186 case VM_PAGER_ERROR: 187 case VM_PAGER_REFAULT: 188 /* 189 * nothing more to do on errors. 190 * VM_PAGER_REFAULT can only mean that the anon was freed, 191 * so again there's nothing to do. 192 */ 193 return FALSE; 194 default: 195 #ifdef DIAGNOSTIC 196 panic("anon_pagein: uvmfault_anonget -> %d", rv); 197 #else 198 return FALSE; 199 #endif 200 } 201 202 /* 203 * ok, we've got the page now. 204 * mark it as dirty, clear its swslot and un-busy it. 205 */ 206 pg = anon->an_page; 207 uvm_swap_free(anon->an_swslot, 1); 208 anon->an_swslot = 0; 209 atomic_clearbits_int(&pg->pg_flags, PG_CLEAN); 210 211 /* deactivate the page (to put it on a page queue) */ 212 pmap_clear_reference(pg); 213 pmap_page_protect(pg, PROT_NONE); 214 uvm_lock_pageq(); 215 uvm_pagedeactivate(pg); 216 uvm_unlock_pageq(); 217 218 return FALSE; 219 } 220