1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 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 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 37 * 38 * 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 * 62 * $FreeBSD$ 63 */ 64 65 #include "opt_rlimit.h" 66 #include "opt_vm.h" 67 68 #include <sys/param.h> 69 #include <sys/systm.h> 70 #include <sys/proc.h> 71 #include <sys/resourcevar.h> 72 #include <sys/buf.h> 73 #include <sys/shm.h> 74 #include <sys/vmmeter.h> 75 #include <sys/sysctl.h> 76 77 #include <sys/kernel.h> 78 #include <sys/unistd.h> 79 80 #include <machine/limits.h> 81 82 #include <vm/vm.h> 83 #include <vm/vm_param.h> 84 #include <sys/lock.h> 85 #include <vm/pmap.h> 86 #include <vm/vm_map.h> 87 #include <vm/vm_page.h> 88 #include <vm/vm_pageout.h> 89 #include <vm/vm_kern.h> 90 #include <vm/vm_extern.h> 91 92 #include <sys/user.h> 93 94 /* 95 * System initialization 96 * 97 * Note: proc0 from proc.h 98 */ 99 100 static void vm_init_limits __P((void *)); 101 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) 102 103 /* 104 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 105 * 106 * Note: run scheduling should be divorced from the vm system. 107 */ 108 static void scheduler __P((void *)); 109 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 110 111 112 static void swapout __P((struct proc *)); 113 114 int 115 kernacc(addr, len, rw) 116 caddr_t addr; 117 int len, rw; 118 { 119 boolean_t rv; 120 vm_offset_t saddr, eaddr; 121 vm_prot_t prot; 122 123 KASSERT((rw & (~VM_PROT_ALL)) == 0, 124 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 125 prot = rw; 126 saddr = trunc_page((vm_offset_t)addr); 127 eaddr = round_page((vm_offset_t)addr + len); 128 vm_map_lock_read(kernel_map); 129 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 130 vm_map_unlock_read(kernel_map); 131 return (rv == TRUE); 132 } 133 134 int 135 useracc(addr, len, rw) 136 caddr_t addr; 137 int len, rw; 138 { 139 boolean_t rv; 140 vm_prot_t prot; 141 vm_map_t map; 142 vm_map_entry_t save_hint; 143 144 KASSERT((rw & (~VM_PROT_ALL)) == 0, 145 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 146 prot = rw; 147 /* 148 * XXX - check separately to disallow access to user area and user 149 * page tables - they are in the map. 150 * 151 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once 152 * only used (as an end address) in trap.c. Use it as an end address 153 * here too. This bogusness has spread. I just fixed where it was 154 * used as a max in vm_mmap.c. 155 */ 156 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS 157 || (vm_offset_t) addr + len < (vm_offset_t) addr) { 158 return (FALSE); 159 } 160 map = &curproc->p_vmspace->vm_map; 161 vm_map_lock_read(map); 162 /* 163 * We save the map hint, and restore it. Useracc appears to distort 164 * the map hint unnecessarily. 165 */ 166 save_hint = map->hint; 167 rv = vm_map_check_protection(map, 168 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot); 169 map->hint = save_hint; 170 vm_map_unlock_read(map); 171 172 return (rv == TRUE); 173 } 174 175 void 176 vslock(addr, len) 177 caddr_t addr; 178 u_int len; 179 { 180 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 181 round_page((vm_offset_t)addr + len), FALSE); 182 } 183 184 void 185 vsunlock(addr, len, dirtied) 186 caddr_t addr; 187 u_int len; 188 int dirtied; 189 { 190 #ifdef lint 191 dirtied++; 192 #endif /* lint */ 193 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 194 round_page((vm_offset_t)addr + len), TRUE); 195 } 196 197 /* 198 * Implement fork's actions on an address space. 199 * Here we arrange for the address space to be copied or referenced, 200 * allocate a user struct (pcb and kernel stack), then call the 201 * machine-dependent layer to fill those in and make the new process 202 * ready to run. The new process is set up so that it returns directly 203 * to user mode to avoid stack copying and relocation problems. 204 */ 205 void 206 vm_fork(p1, p2, flags) 207 register struct proc *p1, *p2; 208 int flags; 209 { 210 register struct user *up; 211 212 if ((flags & RFPROC) == 0) { 213 /* 214 * Divorce the memory, if it is shared, essentially 215 * this changes shared memory amongst threads, into 216 * COW locally. 217 */ 218 if ((flags & RFMEM) == 0) { 219 if (p1->p_vmspace->vm_refcnt > 1) { 220 vmspace_unshare(p1); 221 } 222 } 223 cpu_fork(p1, p2, flags); 224 return; 225 } 226 227 if (flags & RFMEM) { 228 p2->p_vmspace = p1->p_vmspace; 229 p1->p_vmspace->vm_refcnt++; 230 } 231 232 while (vm_page_count_severe()) { 233 VM_WAIT; 234 } 235 236 if ((flags & RFMEM) == 0) { 237 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 238 239 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 240 241 if (p1->p_vmspace->vm_shm) 242 shmfork(p1, p2); 243 } 244 245 pmap_new_proc(p2); 246 247 up = p2->p_addr; 248 249 /* 250 * p_stats currently points at fields in the user struct 251 * but not at &u, instead at p_addr. Copy parts of 252 * p_stats; zero the rest of p_stats (statistics). 253 * 254 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 255 * to share sigacts, so we use the up->u_sigacts. 256 */ 257 p2->p_stats = &up->u_stats; 258 if (p2->p_sigacts == NULL) { 259 if (p2->p_procsig->ps_refcnt != 1) 260 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 261 p2->p_sigacts = &up->u_sigacts; 262 up->u_sigacts = *p1->p_sigacts; 263 } 264 265 bzero(&up->u_stats.pstat_startzero, 266 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 267 (caddr_t) &up->u_stats.pstat_startzero)); 268 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 269 ((caddr_t) &up->u_stats.pstat_endcopy - 270 (caddr_t) &up->u_stats.pstat_startcopy)); 271 272 273 /* 274 * cpu_fork will copy and update the pcb, set up the kernel stack, 275 * and make the child ready to run. 276 */ 277 cpu_fork(p1, p2, flags); 278 } 279 280 /* 281 * Set default limits for VM system. 282 * Called for proc 0, and then inherited by all others. 283 * 284 * XXX should probably act directly on proc0. 285 */ 286 static void 287 vm_init_limits(udata) 288 void *udata; 289 { 290 register struct proc *p = udata; 291 int rss_limit; 292 293 /* 294 * Set up the initial limits on process VM. Set the maximum resident 295 * set size to be half of (reasonably) available memory. Since this 296 * is a soft limit, it comes into effect only when the system is out 297 * of memory - half of main memory helps to favor smaller processes, 298 * and reduces thrashing of the object cache. 299 */ 300 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 301 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 302 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 303 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 304 /* limit the limit to no less than 2MB */ 305 rss_limit = max(cnt.v_free_count, 512); 306 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 307 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 308 } 309 310 void 311 faultin(p) 312 struct proc *p; 313 { 314 int s; 315 316 if ((p->p_flag & P_INMEM) == 0) { 317 318 ++p->p_lock; 319 320 pmap_swapin_proc(p); 321 322 s = splhigh(); 323 324 if (p->p_stat == SRUN) 325 setrunqueue(p); 326 327 p->p_flag |= P_INMEM; 328 329 /* undo the effect of setting SLOCK above */ 330 --p->p_lock; 331 splx(s); 332 333 } 334 } 335 336 /* 337 * This swapin algorithm attempts to swap-in processes only if there 338 * is enough space for them. Of course, if a process waits for a long 339 * time, it will be swapped in anyway. 340 */ 341 /* ARGSUSED*/ 342 static void 343 scheduler(dummy) 344 void *dummy; 345 { 346 register struct proc *p; 347 register int pri; 348 struct proc *pp; 349 int ppri; 350 351 loop: 352 if (vm_page_count_min()) { 353 VM_WAIT; 354 goto loop; 355 } 356 357 pp = NULL; 358 ppri = INT_MIN; 359 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 360 if (p->p_stat == SRUN && 361 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { 362 363 pri = p->p_swtime + p->p_slptime; 364 if ((p->p_flag & P_SWAPINREQ) == 0) { 365 pri -= p->p_nice * 8; 366 } 367 368 /* 369 * if this process is higher priority and there is 370 * enough space, then select this process instead of 371 * the previous selection. 372 */ 373 if (pri > ppri) { 374 pp = p; 375 ppri = pri; 376 } 377 } 378 } 379 380 /* 381 * Nothing to do, back to sleep. 382 */ 383 if ((p = pp) == NULL) { 384 tsleep(&proc0, PVM, "sched", 0); 385 goto loop; 386 } 387 p->p_flag &= ~P_SWAPINREQ; 388 389 /* 390 * We would like to bring someone in. (only if there is space). 391 */ 392 faultin(p); 393 p->p_swtime = 0; 394 goto loop; 395 } 396 397 #ifndef NO_SWAPPING 398 399 #define swappable(p) \ 400 (((p)->p_lock == 0) && \ 401 ((p)->p_flag & (P_TRACED|P_SYSTEM|P_INMEM|P_WEXIT|P_SWAPPING)) == P_INMEM) 402 403 404 /* 405 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 406 */ 407 static int swap_idle_threshold1 = 2; 408 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 409 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 410 411 /* 412 * Swap_idle_threshold2 is the time that a process can be idle before 413 * it will be swapped out, if idle swapping is enabled. 414 */ 415 static int swap_idle_threshold2 = 10; 416 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 417 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 418 419 /* 420 * Swapout is driven by the pageout daemon. Very simple, we find eligible 421 * procs and unwire their u-areas. We try to always "swap" at least one 422 * process in case we need the room for a swapin. 423 * If any procs have been sleeping/stopped for at least maxslp seconds, 424 * they are swapped. Else, we swap the longest-sleeping or stopped process, 425 * if any, otherwise the longest-resident process. 426 */ 427 void 428 swapout_procs(action) 429 int action; 430 { 431 register struct proc *p; 432 struct proc *outp, *outp2; 433 int outpri, outpri2; 434 int didswap = 0; 435 436 outp = outp2 = NULL; 437 outpri = outpri2 = INT_MIN; 438 retry: 439 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 440 struct vmspace *vm; 441 if (!swappable(p)) 442 continue; 443 444 vm = p->p_vmspace; 445 446 switch (p->p_stat) { 447 default: 448 continue; 449 450 case SSLEEP: 451 case SSTOP: 452 /* 453 * do not swapout a realtime process 454 */ 455 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type)) 456 continue; 457 458 /* 459 * Do not swapout a process waiting on a critical 460 * event of some kind. Also guarantee swap_idle_threshold1 461 * time in memory. 462 */ 463 if (((p->p_priority & 0x7f) < PSOCK) || 464 (p->p_slptime < swap_idle_threshold1)) 465 continue; 466 467 /* 468 * If the system is under memory stress, or if we are swapping 469 * idle processes >= swap_idle_threshold2, then swap the process 470 * out. 471 */ 472 if (((action & VM_SWAP_NORMAL) == 0) && 473 (((action & VM_SWAP_IDLE) == 0) || 474 (p->p_slptime < swap_idle_threshold2))) 475 continue; 476 477 ++vm->vm_refcnt; 478 /* 479 * do not swapout a process that is waiting for VM 480 * data structures there is a possible deadlock. 481 */ 482 if (lockmgr(&vm->vm_map.lock, 483 LK_EXCLUSIVE | LK_NOWAIT, 484 (void *)0, curproc)) { 485 vmspace_free(vm); 486 continue; 487 } 488 vm_map_unlock(&vm->vm_map); 489 /* 490 * If the process has been asleep for awhile and had 491 * most of its pages taken away already, swap it out. 492 */ 493 if ((action & VM_SWAP_NORMAL) || 494 ((action & VM_SWAP_IDLE) && 495 (p->p_slptime > swap_idle_threshold2))) { 496 swapout(p); 497 vmspace_free(vm); 498 didswap++; 499 goto retry; 500 } 501 } 502 } 503 /* 504 * If we swapped something out, and another process needed memory, 505 * then wakeup the sched process. 506 */ 507 if (didswap) 508 wakeup(&proc0); 509 } 510 511 static void 512 swapout(p) 513 register struct proc *p; 514 { 515 516 #if defined(SWAP_DEBUG) 517 printf("swapping out %d\n", p->p_pid); 518 #endif 519 ++p->p_stats->p_ru.ru_nswap; 520 /* 521 * remember the process resident count 522 */ 523 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 524 525 (void) splhigh(); 526 p->p_flag &= ~P_INMEM; 527 p->p_flag |= P_SWAPPING; 528 if (p->p_stat == SRUN) 529 remrunqueue(p); 530 (void) spl0(); 531 532 pmap_swapout_proc(p); 533 534 p->p_flag &= ~P_SWAPPING; 535 p->p_swtime = 0; 536 } 537 #endif /* !NO_SWAPPING */ 538