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/vm_radix.h> 110 #include <vm/swap_pager.h> 111 #include <vm/vm_extern.h> 112 #include <vm/uma.h> 113 114 /* the kernel process "vm_daemon" */ 115 static void vm_daemon(void); 116 static struct proc *vmproc; 117 118 static struct kproc_desc vm_kp = { 119 "vmdaemon", 120 vm_daemon, 121 &vmproc 122 }; 123 SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp); 124 125 static int vm_daemon_timeout = 0; 126 SYSCTL_INT(_vm, OID_AUTO, vmdaemon_timeout, CTLFLAG_RW, 127 &vm_daemon_timeout, 0, 128 "Time between vmdaemon runs"); 129 130 static int vm_daemon_needed; 131 static struct mtx vm_daemon_mtx; 132 /* Allow for use by vm_pageout before vm_daemon is initialized. */ 133 MTX_SYSINIT(vm_daemon, &vm_daemon_mtx, "vm daemon", MTX_DEF); 134 135 static void vm_swapout_map_deactivate_pages(vm_map_t, long); 136 static void vm_swapout_object_deactivate(pmap_t, vm_object_t, long); 137 138 static void 139 vm_swapout_object_deactivate_page(pmap_t pmap, vm_page_t m, bool unmap) 140 { 141 142 /* 143 * Ignore unreclaimable wired pages. Repeat the check after busying 144 * since a busy holder may wire the page. 145 */ 146 if (vm_page_wired(m) || !vm_page_tryxbusy(m)) 147 return; 148 149 if (vm_page_wired(m) || !pmap_page_exists_quick(pmap, m)) { 150 vm_page_xunbusy(m); 151 return; 152 } 153 if (!pmap_is_referenced(m)) { 154 if (!vm_page_active(m)) 155 (void)vm_page_try_remove_all(m); 156 else if (unmap && vm_page_try_remove_all(m)) 157 vm_page_deactivate(m); 158 } 159 vm_page_xunbusy(m); 160 } 161 162 /* 163 * vm_swapout_object_deactivate 164 * 165 * Deactivate enough pages to satisfy the inactive target 166 * requirements. 167 * 168 * The object and map must be locked. 169 */ 170 static void 171 vm_swapout_object_deactivate(pmap_t pmap, vm_object_t first_object, 172 long desired) 173 { 174 struct pctrie_iter pages; 175 vm_object_t backing_object, object; 176 vm_page_t m; 177 bool unmap; 178 179 VM_OBJECT_ASSERT_LOCKED(first_object); 180 if ((first_object->flags & OBJ_FICTITIOUS) != 0) 181 return; 182 for (object = first_object;; object = backing_object) { 183 if (pmap_resident_count(pmap) <= desired) 184 goto unlock_return; 185 VM_OBJECT_ASSERT_LOCKED(object); 186 if ((object->flags & OBJ_UNMANAGED) != 0 || 187 blockcount_read(&object->paging_in_progress) > 0) 188 goto unlock_return; 189 190 unmap = true; 191 if (object->shadow_count > 1) 192 unmap = false; 193 194 /* 195 * Scan the object's entire memory queue. 196 */ 197 vm_page_iter_init(&pages, object); 198 VM_RADIX_FOREACH(m, &pages) { 199 if (pmap_resident_count(pmap) <= desired) 200 goto unlock_return; 201 if (should_yield()) 202 goto unlock_return; 203 vm_swapout_object_deactivate_page(pmap, m, unmap); 204 } 205 if ((backing_object = object->backing_object) == NULL) 206 goto unlock_return; 207 VM_OBJECT_RLOCK(backing_object); 208 if (object != first_object) 209 VM_OBJECT_RUNLOCK(object); 210 } 211 unlock_return: 212 if (object != first_object) 213 VM_OBJECT_RUNLOCK(object); 214 } 215 216 /* 217 * deactivate some number of pages in a map, try to do it fairly, but 218 * that is really hard to do. 219 */ 220 static void 221 vm_swapout_map_deactivate_pages(vm_map_t map, long desired) 222 { 223 vm_map_entry_t tmpe; 224 vm_object_t obj, bigobj; 225 int nothingwired; 226 227 if (!vm_map_trylock_read(map)) 228 return; 229 230 bigobj = NULL; 231 nothingwired = TRUE; 232 233 /* 234 * first, search out the biggest object, and try to free pages from 235 * that. 236 */ 237 VM_MAP_ENTRY_FOREACH(tmpe, map) { 238 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 239 obj = tmpe->object.vm_object; 240 if (obj != NULL && VM_OBJECT_TRYRLOCK(obj)) { 241 if (obj->shadow_count <= 1 && 242 (bigobj == NULL || 243 bigobj->resident_page_count < 244 obj->resident_page_count)) { 245 if (bigobj != NULL) 246 VM_OBJECT_RUNLOCK(bigobj); 247 bigobj = obj; 248 } else 249 VM_OBJECT_RUNLOCK(obj); 250 } 251 } 252 if (tmpe->wired_count > 0) 253 nothingwired = FALSE; 254 } 255 256 if (bigobj != NULL) { 257 vm_swapout_object_deactivate(map->pmap, bigobj, desired); 258 VM_OBJECT_RUNLOCK(bigobj); 259 } 260 /* 261 * Next, hunt around for other pages to deactivate. We actually 262 * do this search sort of wrong -- .text first is not the best idea. 263 */ 264 VM_MAP_ENTRY_FOREACH(tmpe, map) { 265 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 266 break; 267 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 268 obj = tmpe->object.vm_object; 269 if (obj != NULL) { 270 VM_OBJECT_RLOCK(obj); 271 vm_swapout_object_deactivate(map->pmap, obj, 272 desired); 273 VM_OBJECT_RUNLOCK(obj); 274 } 275 } 276 } 277 278 /* 279 * Remove all mappings if a process is swapped out, this will free page 280 * table pages. 281 */ 282 if (desired == 0 && nothingwired) { 283 pmap_remove(vm_map_pmap(map), vm_map_min(map), 284 vm_map_max(map)); 285 } 286 287 vm_map_unlock_read(map); 288 } 289 290 static void 291 vm_daemon(void) 292 { 293 struct rlimit rsslim; 294 struct proc *p; 295 struct thread *td; 296 struct vmspace *vm; 297 int breakout, tryagain, attempts; 298 uint64_t rsize, ravailable; 299 300 if (racct_enable && vm_daemon_timeout == 0) 301 vm_daemon_timeout = hz; 302 303 while (TRUE) { 304 mtx_lock(&vm_daemon_mtx); 305 msleep(&vm_daemon_needed, &vm_daemon_mtx, PPAUSE, "psleep", 306 vm_daemon_timeout); 307 mtx_unlock(&vm_daemon_mtx); 308 309 /* 310 * scan the processes for exceeding their rlimits or if 311 * process is swapped out -- deactivate pages 312 */ 313 tryagain = 0; 314 attempts = 0; 315 again: 316 attempts++; 317 sx_slock(&allproc_lock); 318 FOREACH_PROC_IN_SYSTEM(p) { 319 vm_pindex_t limit, size; 320 321 /* 322 * if this is a system process or if we have already 323 * looked at this process, skip it. 324 */ 325 PROC_LOCK(p); 326 if (p->p_state != PRS_NORMAL || 327 p->p_flag & (P_INEXEC | P_SYSTEM | P_WEXIT)) { 328 PROC_UNLOCK(p); 329 continue; 330 } 331 /* 332 * if the process is in a non-running type state, 333 * don't touch it. 334 */ 335 breakout = 0; 336 FOREACH_THREAD_IN_PROC(p, td) { 337 thread_lock(td); 338 if (!TD_ON_RUNQ(td) && 339 !TD_IS_RUNNING(td) && 340 !TD_IS_SLEEPING(td) && 341 !TD_IS_SUSPENDED(td)) { 342 thread_unlock(td); 343 breakout = 1; 344 break; 345 } 346 thread_unlock(td); 347 } 348 if (breakout) { 349 PROC_UNLOCK(p); 350 continue; 351 } 352 /* 353 * get a limit 354 */ 355 lim_rlimit_proc(p, RLIMIT_RSS, &rsslim); 356 limit = OFF_TO_IDX( 357 qmin(rsslim.rlim_cur, rsslim.rlim_max)); 358 359 vm = vmspace_acquire_ref(p); 360 _PHOLD(p); 361 PROC_UNLOCK(p); 362 if (vm == NULL) { 363 PRELE(p); 364 continue; 365 } 366 sx_sunlock(&allproc_lock); 367 368 size = vmspace_resident_count(vm); 369 if (size >= limit) { 370 vm_swapout_map_deactivate_pages( 371 &vm->vm_map, limit); 372 size = vmspace_resident_count(vm); 373 } 374 if (racct_enable) { 375 rsize = IDX_TO_OFF(size); 376 PROC_LOCK(p); 377 if (p->p_state == PRS_NORMAL) 378 racct_set(p, RACCT_RSS, rsize); 379 ravailable = racct_get_available(p, RACCT_RSS); 380 PROC_UNLOCK(p); 381 if (rsize > ravailable) { 382 /* 383 * Don't be overly aggressive; this 384 * might be an innocent process, 385 * and the limit could've been exceeded 386 * by some memory hog. Don't try 387 * to deactivate more than 1/4th 388 * of process' resident set size. 389 */ 390 if (attempts <= 8) { 391 if (ravailable < rsize - 392 (rsize / 4)) { 393 ravailable = rsize - 394 (rsize / 4); 395 } 396 } 397 vm_swapout_map_deactivate_pages( 398 &vm->vm_map, 399 OFF_TO_IDX(ravailable)); 400 /* Update RSS usage after paging out. */ 401 size = vmspace_resident_count(vm); 402 rsize = IDX_TO_OFF(size); 403 PROC_LOCK(p); 404 if (p->p_state == PRS_NORMAL) 405 racct_set(p, RACCT_RSS, rsize); 406 PROC_UNLOCK(p); 407 if (rsize > ravailable) 408 tryagain = 1; 409 } 410 } 411 vmspace_free(vm); 412 sx_slock(&allproc_lock); 413 PRELE(p); 414 } 415 sx_sunlock(&allproc_lock); 416 if (tryagain != 0 && attempts <= 10) { 417 maybe_yield(); 418 goto again; 419 } 420 } 421 } 422