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/shm.h> 73 #include <sys/vmmeter.h> 74 #include <sys/sysctl.h> 75 76 #include <sys/kernel.h> 77 #include <sys/ktr.h> 78 #include <sys/mutex.h> 79 #include <sys/unistd.h> 80 81 #include <machine/limits.h> 82 83 #include <vm/vm.h> 84 #include <vm/vm_param.h> 85 #include <sys/lock.h> 86 #include <vm/pmap.h> 87 #include <vm/vm_map.h> 88 #include <vm/vm_page.h> 89 #include <vm/vm_pageout.h> 90 #include <vm/vm_kern.h> 91 #include <vm/vm_extern.h> 92 93 #include <sys/user.h> 94 95 /* 96 * System initialization 97 * 98 * Note: proc0 from proc.h 99 */ 100 101 static void vm_init_limits __P((void *)); 102 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) 103 104 /* 105 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 106 * 107 * Note: run scheduling should be divorced from the vm system. 108 */ 109 static void scheduler __P((void *)); 110 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 111 112 113 static void swapout __P((struct proc *)); 114 115 int 116 kernacc(addr, len, rw) 117 caddr_t addr; 118 int len, rw; 119 { 120 boolean_t rv; 121 vm_offset_t saddr, eaddr; 122 vm_prot_t prot; 123 124 KASSERT((rw & (~VM_PROT_ALL)) == 0, 125 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 126 prot = rw; 127 saddr = trunc_page((vm_offset_t)addr); 128 eaddr = round_page((vm_offset_t)addr + len); 129 vm_map_lock_read(kernel_map); 130 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 131 vm_map_unlock_read(kernel_map); 132 return (rv == TRUE); 133 } 134 135 int 136 useracc(addr, len, rw) 137 caddr_t addr; 138 int len, rw; 139 { 140 boolean_t rv; 141 vm_prot_t prot; 142 vm_map_t map; 143 vm_map_entry_t save_hint; 144 145 KASSERT((rw & (~VM_PROT_ALL)) == 0, 146 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 147 prot = rw; 148 /* 149 * XXX - check separately to disallow access to user area and user 150 * page tables - they are in the map. 151 * 152 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once 153 * only used (as an end address) in trap.c. Use it as an end address 154 * here too. This bogusness has spread. I just fixed where it was 155 * used as a max in vm_mmap.c. 156 */ 157 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS 158 || (vm_offset_t) addr + len < (vm_offset_t) addr) { 159 return (FALSE); 160 } 161 map = &curproc->p_vmspace->vm_map; 162 vm_map_lock_read(map); 163 /* 164 * We save the map hint, and restore it. Useracc appears to distort 165 * the map hint unnecessarily. 166 */ 167 save_hint = map->hint; 168 rv = vm_map_check_protection(map, 169 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot); 170 map->hint = save_hint; 171 vm_map_unlock_read(map); 172 173 return (rv == TRUE); 174 } 175 176 void 177 vslock(addr, len) 178 caddr_t addr; 179 u_int len; 180 { 181 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 182 round_page((vm_offset_t)addr + len), FALSE); 183 } 184 185 void 186 vsunlock(addr, len) 187 caddr_t addr; 188 u_int len; 189 { 190 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 191 round_page((vm_offset_t)addr + len), TRUE); 192 } 193 194 /* 195 * Implement fork's actions on an address space. 196 * Here we arrange for the address space to be copied or referenced, 197 * allocate a user struct (pcb and kernel stack), then call the 198 * machine-dependent layer to fill those in and make the new process 199 * ready to run. The new process is set up so that it returns directly 200 * to user mode to avoid stack copying and relocation problems. 201 */ 202 void 203 vm_fork(p1, p2, flags) 204 register struct proc *p1, *p2; 205 int flags; 206 { 207 register struct user *up; 208 209 if ((flags & RFPROC) == 0) { 210 /* 211 * Divorce the memory, if it is shared, essentially 212 * this changes shared memory amongst threads, into 213 * COW locally. 214 */ 215 if ((flags & RFMEM) == 0) { 216 if (p1->p_vmspace->vm_refcnt > 1) { 217 vmspace_unshare(p1); 218 } 219 } 220 cpu_fork(p1, p2, flags); 221 return; 222 } 223 224 if (flags & RFMEM) { 225 p2->p_vmspace = p1->p_vmspace; 226 p1->p_vmspace->vm_refcnt++; 227 } 228 229 while (vm_page_count_severe()) { 230 VM_WAIT; 231 } 232 233 if ((flags & RFMEM) == 0) { 234 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 235 236 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 237 238 if (p1->p_vmspace->vm_shm) 239 shmfork(p1, p2); 240 } 241 242 pmap_new_proc(p2); 243 244 up = p2->p_addr; 245 246 /* 247 * p_stats currently points at fields in the user struct 248 * but not at &u, instead at p_addr. Copy parts of 249 * p_stats; zero the rest of p_stats (statistics). 250 * 251 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 252 * to share sigacts, so we use the up->u_sigacts. 253 */ 254 p2->p_stats = &up->u_stats; 255 if (p2->p_sigacts == NULL) { 256 if (p2->p_procsig->ps_refcnt != 1) 257 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 258 p2->p_sigacts = &up->u_sigacts; 259 up->u_sigacts = *p1->p_sigacts; 260 } 261 262 bzero(&up->u_stats.pstat_startzero, 263 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 264 (caddr_t) &up->u_stats.pstat_startzero)); 265 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 266 ((caddr_t) &up->u_stats.pstat_endcopy - 267 (caddr_t) &up->u_stats.pstat_startcopy)); 268 269 270 /* 271 * cpu_fork will copy and update the pcb, set up the kernel stack, 272 * and make the child ready to run. 273 */ 274 cpu_fork(p1, p2, flags); 275 } 276 277 /* 278 * Set default limits for VM system. 279 * Called for proc 0, and then inherited by all others. 280 * 281 * XXX should probably act directly on proc0. 282 */ 283 static void 284 vm_init_limits(udata) 285 void *udata; 286 { 287 register struct proc *p = udata; 288 int rss_limit; 289 290 /* 291 * Set up the initial limits on process VM. Set the maximum resident 292 * set size to be half of (reasonably) available memory. Since this 293 * is a soft limit, it comes into effect only when the system is out 294 * of memory - half of main memory helps to favor smaller processes, 295 * and reduces thrashing of the object cache. 296 */ 297 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 298 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 299 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 300 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 301 /* limit the limit to no less than 2MB */ 302 rss_limit = max(cnt.v_free_count, 512); 303 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 304 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 305 } 306 307 void 308 faultin(p) 309 struct proc *p; 310 { 311 int s; 312 313 if ((p->p_flag & P_INMEM) == 0) { 314 315 ++p->p_lock; 316 317 pmap_swapin_proc(p); 318 319 s = splhigh(); 320 321 mtx_enter(&sched_lock, MTX_SPIN); 322 if (p->p_stat == SRUN) { 323 setrunqueue(p); 324 } 325 mtx_exit(&sched_lock, MTX_SPIN); 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 * Giant is still held at this point, to be released in tsleep. 342 */ 343 /* ARGSUSED*/ 344 static void 345 scheduler(dummy) 346 void *dummy; 347 { 348 register struct proc *p; 349 register int pri; 350 struct proc *pp; 351 int ppri; 352 353 mtx_assert(&Giant, MA_OWNED); 354 355 loop: 356 if (vm_page_count_min()) { 357 VM_WAIT; 358 goto loop; 359 } 360 361 pp = NULL; 362 ppri = INT_MIN; 363 ALLPROC_LOCK(AP_SHARED); 364 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 365 mtx_enter(&sched_lock, MTX_SPIN); 366 if (p->p_stat == SRUN && 367 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { 368 369 pri = p->p_swtime + p->p_slptime; 370 if ((p->p_flag & P_SWAPINREQ) == 0) { 371 pri -= p->p_nice * 8; 372 } 373 374 /* 375 * if this process is higher priority and there is 376 * enough space, then select this process instead of 377 * the previous selection. 378 */ 379 if (pri > ppri) { 380 pp = p; 381 ppri = pri; 382 } 383 } 384 mtx_exit(&sched_lock, MTX_SPIN); 385 } 386 ALLPROC_LOCK(AP_RELEASE); 387 388 /* 389 * Nothing to do, back to sleep. 390 */ 391 if ((p = pp) == NULL) { 392 tsleep(&proc0, PVM, "sched", 0); 393 goto loop; 394 } 395 p->p_flag &= ~P_SWAPINREQ; 396 397 /* 398 * We would like to bring someone in. (only if there is space). 399 */ 400 faultin(p); 401 p->p_swtime = 0; 402 goto loop; 403 } 404 405 #ifndef NO_SWAPPING 406 407 #define swappable(p) \ 408 (((p)->p_lock == 0) && \ 409 ((p)->p_flag & (P_TRACED|P_SYSTEM|P_INMEM|P_WEXIT|P_SWAPPING)) == P_INMEM) 410 411 412 /* 413 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 414 */ 415 static int swap_idle_threshold1 = 2; 416 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 417 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 418 419 /* 420 * Swap_idle_threshold2 is the time that a process can be idle before 421 * it will be swapped out, if idle swapping is enabled. 422 */ 423 static int swap_idle_threshold2 = 10; 424 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 425 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 426 427 /* 428 * Swapout is driven by the pageout daemon. Very simple, we find eligible 429 * procs and unwire their u-areas. We try to always "swap" at least one 430 * process in case we need the room for a swapin. 431 * If any procs have been sleeping/stopped for at least maxslp seconds, 432 * they are swapped. Else, we swap the longest-sleeping or stopped process, 433 * if any, otherwise the longest-resident process. 434 */ 435 void 436 swapout_procs(action) 437 int action; 438 { 439 register struct proc *p; 440 struct proc *outp, *outp2; 441 int outpri, outpri2; 442 int didswap = 0; 443 444 outp = outp2 = NULL; 445 outpri = outpri2 = INT_MIN; 446 ALLPROC_LOCK(AP_SHARED); 447 retry: 448 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 449 struct vmspace *vm; 450 if (!swappable(p)) 451 continue; 452 453 vm = p->p_vmspace; 454 455 mtx_enter(&sched_lock, MTX_SPIN); 456 switch (p->p_stat) { 457 default: 458 mtx_exit(&sched_lock, MTX_SPIN); 459 continue; 460 461 case SSLEEP: 462 case SSTOP: 463 /* 464 * do not swapout a realtime process 465 */ 466 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type)) { 467 mtx_exit(&sched_lock, MTX_SPIN); 468 continue; 469 } 470 471 /* 472 * Do not swapout a process waiting on a critical 473 * event of some kind. Also guarantee swap_idle_threshold1 474 * time in memory. 475 */ 476 if (((p->p_priority & 0x7f) < PSOCK) || 477 (p->p_slptime < swap_idle_threshold1)) { 478 mtx_exit(&sched_lock, MTX_SPIN); 479 continue; 480 } 481 mtx_exit(&sched_lock, MTX_SPIN); 482 483 /* 484 * If the system is under memory stress, or if we are swapping 485 * idle processes >= swap_idle_threshold2, then swap the process 486 * out. 487 */ 488 if (((action & VM_SWAP_NORMAL) == 0) && 489 (((action & VM_SWAP_IDLE) == 0) || 490 (p->p_slptime < swap_idle_threshold2))) 491 continue; 492 493 ++vm->vm_refcnt; 494 /* 495 * do not swapout a process that is waiting for VM 496 * data structures there is a possible deadlock. 497 */ 498 if (lockmgr(&vm->vm_map.lock, 499 LK_EXCLUSIVE | LK_NOWAIT, 500 (void *)0, curproc)) { 501 vmspace_free(vm); 502 continue; 503 } 504 vm_map_unlock(&vm->vm_map); 505 /* 506 * If the process has been asleep for awhile and had 507 * most of its pages taken away already, swap it out. 508 */ 509 if ((action & VM_SWAP_NORMAL) || 510 ((action & VM_SWAP_IDLE) && 511 (p->p_slptime > swap_idle_threshold2))) { 512 swapout(p); 513 vmspace_free(vm); 514 didswap++; 515 goto retry; 516 } 517 } 518 } 519 ALLPROC_LOCK(AP_RELEASE); 520 /* 521 * If we swapped something out, and another process needed memory, 522 * then wakeup the sched process. 523 */ 524 if (didswap) 525 wakeup(&proc0); 526 } 527 528 static void 529 swapout(p) 530 register struct proc *p; 531 { 532 533 #if defined(SWAP_DEBUG) 534 printf("swapping out %d\n", p->p_pid); 535 #endif 536 ++p->p_stats->p_ru.ru_nswap; 537 /* 538 * remember the process resident count 539 */ 540 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 541 542 (void) splhigh(); 543 mtx_enter(&sched_lock, MTX_SPIN); 544 p->p_flag &= ~P_INMEM; 545 p->p_flag |= P_SWAPPING; 546 if (p->p_stat == SRUN) 547 remrunqueue(p); 548 mtx_exit(&sched_lock, MTX_SPIN); 549 (void) spl0(); 550 551 pmap_swapout_proc(p); 552 553 p->p_flag &= ~P_SWAPPING; 554 p->p_swtime = 0; 555 } 556 #endif /* !NO_SWAPPING */ 557