1 /*- 2 * SPDX-License-Identifier: (BSD-4-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991 Regents of the University of California. 5 * All rights reserved. 6 * Copyright (c) 1994 John S. Dyson 7 * All rights reserved. 8 * Copyright (c) 1994 David Greenman 9 * All rights reserved. 10 * Copyright (c) 2005 Yahoo! Technologies Norway AS 11 * All rights reserved. 12 * 13 * This code is derived from software contributed to Berkeley by 14 * The Mach Operating System project at Carnegie-Mellon University. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 3. All advertising materials mentioning features or use of this software 25 * must display the following acknowledgement: 26 * This product includes software developed by the University of 27 * California, Berkeley and its contributors. 28 * 4. Neither the name of the University nor the names of its contributors 29 * may be used to endorse or promote products derived from this software 30 * without specific prior written permission. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. 43 * 44 * 45 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 46 * All rights reserved. 47 * 48 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 49 * 50 * Permission to use, copy, modify and distribute this software and 51 * its documentation is hereby granted, provided that both the copyright 52 * notice and this permission notice appear in all copies of the 53 * software, derivative works or modified versions, and any portions 54 * thereof, and that both notices appear in supporting documentation. 55 * 56 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 57 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 58 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 59 * 60 * Carnegie Mellon requests users of this software to return to 61 * 62 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 63 * School of Computer Science 64 * Carnegie Mellon University 65 * Pittsburgh PA 15213-3890 66 * 67 * any improvements or extensions that they make and grant Carnegie the 68 * rights to redistribute these changes. 69 */ 70 71 #include "opt_kstack_pages.h" 72 #include "opt_kstack_max_pages.h" 73 #include "opt_vm.h" 74 75 #include <sys/param.h> 76 #include <sys/systm.h> 77 #include <sys/limits.h> 78 #include <sys/kernel.h> 79 #include <sys/eventhandler.h> 80 #include <sys/lock.h> 81 #include <sys/mutex.h> 82 #include <sys/proc.h> 83 #include <sys/kthread.h> 84 #include <sys/ktr.h> 85 #include <sys/mount.h> 86 #include <sys/racct.h> 87 #include <sys/resourcevar.h> 88 #include <sys/refcount.h> 89 #include <sys/sched.h> 90 #include <sys/sdt.h> 91 #include <sys/signalvar.h> 92 #include <sys/smp.h> 93 #include <sys/time.h> 94 #include <sys/vnode.h> 95 #include <sys/vmmeter.h> 96 #include <sys/rwlock.h> 97 #include <sys/sx.h> 98 #include <sys/sysctl.h> 99 100 #include <vm/vm.h> 101 #include <vm/vm_param.h> 102 #include <vm/vm_kern.h> 103 #include <vm/vm_object.h> 104 #include <vm/vm_page.h> 105 #include <vm/vm_map.h> 106 #include <vm/vm_pageout.h> 107 #include <vm/vm_pager.h> 108 #include <vm/vm_phys.h> 109 #include <vm/swap_pager.h> 110 #include <vm/vm_extern.h> 111 #include <vm/uma.h> 112 113 /* the kernel process "vm_daemon" */ 114 static void vm_daemon(void); 115 static struct proc *vmproc; 116 117 static struct kproc_desc vm_kp = { 118 "vmdaemon", 119 vm_daemon, 120 &vmproc 121 }; 122 SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp); 123 124 static int vm_daemon_timeout = 0; 125 SYSCTL_INT(_vm, OID_AUTO, vmdaemon_timeout, CTLFLAG_RW, 126 &vm_daemon_timeout, 0, 127 "Time between vmdaemon runs"); 128 129 static int vm_daemon_needed; 130 static struct mtx vm_daemon_mtx; 131 /* Allow for use by vm_pageout before vm_daemon is initialized. */ 132 MTX_SYSINIT(vm_daemon, &vm_daemon_mtx, "vm daemon", MTX_DEF); 133 134 static void vm_swapout_map_deactivate_pages(vm_map_t, long); 135 static void vm_swapout_object_deactivate(pmap_t, vm_object_t, long); 136 137 static void 138 vm_swapout_object_deactivate_page(pmap_t pmap, vm_page_t m, bool unmap) 139 { 140 141 /* 142 * Ignore unreclaimable wired pages. Repeat the check after busying 143 * since a busy holder may wire the page. 144 */ 145 if (vm_page_wired(m) || !vm_page_tryxbusy(m)) 146 return; 147 148 if (vm_page_wired(m) || !pmap_page_exists_quick(pmap, m)) { 149 vm_page_xunbusy(m); 150 return; 151 } 152 if (!pmap_is_referenced(m)) { 153 if (!vm_page_active(m)) 154 (void)vm_page_try_remove_all(m); 155 else if (unmap && vm_page_try_remove_all(m)) 156 vm_page_deactivate(m); 157 } 158 vm_page_xunbusy(m); 159 } 160 161 /* 162 * vm_swapout_object_deactivate 163 * 164 * Deactivate enough pages to satisfy the inactive target 165 * requirements. 166 * 167 * The object and map must be locked. 168 */ 169 static void 170 vm_swapout_object_deactivate(pmap_t pmap, vm_object_t first_object, 171 long desired) 172 { 173 vm_object_t backing_object, object; 174 vm_page_t m; 175 bool unmap; 176 177 VM_OBJECT_ASSERT_LOCKED(first_object); 178 if ((first_object->flags & OBJ_FICTITIOUS) != 0) 179 return; 180 for (object = first_object;; object = backing_object) { 181 if (pmap_resident_count(pmap) <= desired) 182 goto unlock_return; 183 VM_OBJECT_ASSERT_LOCKED(object); 184 if ((object->flags & OBJ_UNMANAGED) != 0 || 185 blockcount_read(&object->paging_in_progress) > 0) 186 goto unlock_return; 187 188 unmap = true; 189 if (object->shadow_count > 1) 190 unmap = false; 191 192 /* 193 * Scan the object's entire memory queue. 194 */ 195 TAILQ_FOREACH(m, &object->memq, listq) { 196 if (pmap_resident_count(pmap) <= desired) 197 goto unlock_return; 198 if (should_yield()) 199 goto unlock_return; 200 vm_swapout_object_deactivate_page(pmap, m, unmap); 201 } 202 if ((backing_object = object->backing_object) == NULL) 203 goto unlock_return; 204 VM_OBJECT_RLOCK(backing_object); 205 if (object != first_object) 206 VM_OBJECT_RUNLOCK(object); 207 } 208 unlock_return: 209 if (object != first_object) 210 VM_OBJECT_RUNLOCK(object); 211 } 212 213 /* 214 * deactivate some number of pages in a map, try to do it fairly, but 215 * that is really hard to do. 216 */ 217 static void 218 vm_swapout_map_deactivate_pages(vm_map_t map, long desired) 219 { 220 vm_map_entry_t tmpe; 221 vm_object_t obj, bigobj; 222 int nothingwired; 223 224 if (!vm_map_trylock_read(map)) 225 return; 226 227 bigobj = NULL; 228 nothingwired = TRUE; 229 230 /* 231 * first, search out the biggest object, and try to free pages from 232 * that. 233 */ 234 VM_MAP_ENTRY_FOREACH(tmpe, map) { 235 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 236 obj = tmpe->object.vm_object; 237 if (obj != NULL && VM_OBJECT_TRYRLOCK(obj)) { 238 if (obj->shadow_count <= 1 && 239 (bigobj == NULL || 240 bigobj->resident_page_count < 241 obj->resident_page_count)) { 242 if (bigobj != NULL) 243 VM_OBJECT_RUNLOCK(bigobj); 244 bigobj = obj; 245 } else 246 VM_OBJECT_RUNLOCK(obj); 247 } 248 } 249 if (tmpe->wired_count > 0) 250 nothingwired = FALSE; 251 } 252 253 if (bigobj != NULL) { 254 vm_swapout_object_deactivate(map->pmap, bigobj, desired); 255 VM_OBJECT_RUNLOCK(bigobj); 256 } 257 /* 258 * Next, hunt around for other pages to deactivate. We actually 259 * do this search sort of wrong -- .text first is not the best idea. 260 */ 261 VM_MAP_ENTRY_FOREACH(tmpe, map) { 262 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 263 break; 264 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 265 obj = tmpe->object.vm_object; 266 if (obj != NULL) { 267 VM_OBJECT_RLOCK(obj); 268 vm_swapout_object_deactivate(map->pmap, obj, 269 desired); 270 VM_OBJECT_RUNLOCK(obj); 271 } 272 } 273 } 274 275 /* 276 * Remove all mappings if a process is swapped out, this will free page 277 * table pages. 278 */ 279 if (desired == 0 && nothingwired) { 280 pmap_remove(vm_map_pmap(map), vm_map_min(map), 281 vm_map_max(map)); 282 } 283 284 vm_map_unlock_read(map); 285 } 286 287 static void 288 vm_daemon(void) 289 { 290 struct rlimit rsslim; 291 struct proc *p; 292 struct thread *td; 293 struct vmspace *vm; 294 int breakout, tryagain, attempts; 295 uint64_t rsize, ravailable; 296 297 if (racct_enable && vm_daemon_timeout == 0) 298 vm_daemon_timeout = hz; 299 300 while (TRUE) { 301 mtx_lock(&vm_daemon_mtx); 302 msleep(&vm_daemon_needed, &vm_daemon_mtx, PPAUSE, "psleep", 303 vm_daemon_timeout); 304 mtx_unlock(&vm_daemon_mtx); 305 306 /* 307 * scan the processes for exceeding their rlimits or if 308 * process is swapped out -- deactivate pages 309 */ 310 tryagain = 0; 311 attempts = 0; 312 again: 313 attempts++; 314 sx_slock(&allproc_lock); 315 FOREACH_PROC_IN_SYSTEM(p) { 316 vm_pindex_t limit, size; 317 318 /* 319 * if this is a system process or if we have already 320 * looked at this process, skip it. 321 */ 322 PROC_LOCK(p); 323 if (p->p_state != PRS_NORMAL || 324 p->p_flag & (P_INEXEC | P_SYSTEM | P_WEXIT)) { 325 PROC_UNLOCK(p); 326 continue; 327 } 328 /* 329 * if the process is in a non-running type state, 330 * don't touch it. 331 */ 332 breakout = 0; 333 FOREACH_THREAD_IN_PROC(p, td) { 334 thread_lock(td); 335 if (!TD_ON_RUNQ(td) && 336 !TD_IS_RUNNING(td) && 337 !TD_IS_SLEEPING(td) && 338 !TD_IS_SUSPENDED(td)) { 339 thread_unlock(td); 340 breakout = 1; 341 break; 342 } 343 thread_unlock(td); 344 } 345 if (breakout) { 346 PROC_UNLOCK(p); 347 continue; 348 } 349 /* 350 * get a limit 351 */ 352 lim_rlimit_proc(p, RLIMIT_RSS, &rsslim); 353 limit = OFF_TO_IDX( 354 qmin(rsslim.rlim_cur, rsslim.rlim_max)); 355 356 vm = vmspace_acquire_ref(p); 357 _PHOLD(p); 358 PROC_UNLOCK(p); 359 if (vm == NULL) { 360 PRELE(p); 361 continue; 362 } 363 sx_sunlock(&allproc_lock); 364 365 size = vmspace_resident_count(vm); 366 if (size >= limit) { 367 vm_swapout_map_deactivate_pages( 368 &vm->vm_map, limit); 369 size = vmspace_resident_count(vm); 370 } 371 if (racct_enable) { 372 rsize = IDX_TO_OFF(size); 373 PROC_LOCK(p); 374 if (p->p_state == PRS_NORMAL) 375 racct_set(p, RACCT_RSS, rsize); 376 ravailable = racct_get_available(p, RACCT_RSS); 377 PROC_UNLOCK(p); 378 if (rsize > ravailable) { 379 /* 380 * Don't be overly aggressive; this 381 * might be an innocent process, 382 * and the limit could've been exceeded 383 * by some memory hog. Don't try 384 * to deactivate more than 1/4th 385 * of process' resident set size. 386 */ 387 if (attempts <= 8) { 388 if (ravailable < rsize - 389 (rsize / 4)) { 390 ravailable = rsize - 391 (rsize / 4); 392 } 393 } 394 vm_swapout_map_deactivate_pages( 395 &vm->vm_map, 396 OFF_TO_IDX(ravailable)); 397 /* Update RSS usage after paging out. */ 398 size = vmspace_resident_count(vm); 399 rsize = IDX_TO_OFF(size); 400 PROC_LOCK(p); 401 if (p->p_state == PRS_NORMAL) 402 racct_set(p, RACCT_RSS, rsize); 403 PROC_UNLOCK(p); 404 if (rsize > ravailable) 405 tryagain = 1; 406 } 407 } 408 vmspace_free(vm); 409 sx_slock(&allproc_lock); 410 PRELE(p); 411 } 412 sx_sunlock(&allproc_lock); 413 if (tryagain != 0 && attempts <= 10) { 414 maybe_yield(); 415 goto again; 416 } 417 } 418 } 419