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_vm.h" 66 67 #include <sys/param.h> 68 #include <sys/systm.h> 69 #include <sys/lock.h> 70 #include <sys/mutex.h> 71 #include <sys/proc.h> 72 #include <sys/resourcevar.h> 73 #include <sys/shm.h> 74 #include <sys/vmmeter.h> 75 #include <sys/sx.h> 76 #include <sys/sysctl.h> 77 78 #include <sys/kernel.h> 79 #include <sys/ktr.h> 80 #include <sys/unistd.h> 81 82 #include <machine/limits.h> 83 84 #include <vm/vm.h> 85 #include <vm/vm_param.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 extern int maxslp; 96 97 /* 98 * System initialization 99 * 100 * Note: proc0 from proc.h 101 */ 102 static void vm_init_limits(void *); 103 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) 104 105 /* 106 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 107 * 108 * Note: run scheduling should be divorced from the vm system. 109 */ 110 static void scheduler(void *); 111 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 112 113 #ifndef NO_SWAPPING 114 static void swapout(struct proc *); 115 #endif 116 117 /* 118 * MPSAFE 119 */ 120 int 121 kernacc(addr, len, rw) 122 caddr_t addr; 123 int len, rw; 124 { 125 boolean_t rv; 126 vm_offset_t saddr, eaddr; 127 vm_prot_t prot; 128 129 KASSERT((rw & ~VM_PROT_ALL) == 0, 130 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 131 prot = rw; 132 saddr = trunc_page((vm_offset_t)addr); 133 eaddr = round_page((vm_offset_t)addr + len); 134 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 135 return (rv == TRUE); 136 } 137 138 /* 139 * MPSAFE 140 */ 141 int 142 useracc(addr, len, rw) 143 caddr_t addr; 144 int len, rw; 145 { 146 boolean_t rv; 147 vm_prot_t prot; 148 149 KASSERT((rw & ~VM_PROT_ALL) == 0, 150 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 151 prot = rw; 152 /* 153 * XXX - check separately to disallow access to user area and user 154 * page tables - they are in the map. 155 * 156 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once 157 * only used (as an end address) in trap.c. Use it as an end address 158 * here too. This bogusness has spread. I just fixed where it was 159 * used as a max in vm_mmap.c. 160 */ 161 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS 162 || (vm_offset_t) addr + len < (vm_offset_t) addr) { 163 return (FALSE); 164 } 165 rv = vm_map_check_protection(&curproc->p_vmspace->vm_map, 166 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), 167 prot); 168 return (rv == TRUE); 169 } 170 171 /* 172 * MPSAFE 173 */ 174 void 175 vslock(addr, len) 176 caddr_t addr; 177 u_int len; 178 { 179 180 vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 181 round_page((vm_offset_t)addr + len), FALSE); 182 } 183 184 /* 185 * MPSAFE 186 */ 187 void 188 vsunlock(addr, len) 189 caddr_t addr; 190 u_int len; 191 { 192 193 vm_map_unwire(&curproc->p_vmspace->vm_map, 194 trunc_page((vm_offset_t)addr), 195 round_page((vm_offset_t)addr + len), FALSE); 196 } 197 198 /* 199 * Implement fork's actions on an address space. 200 * Here we arrange for the address space to be copied or referenced, 201 * allocate a user struct (pcb and kernel stack), then call the 202 * machine-dependent layer to fill those in and make the new process 203 * ready to run. The new process is set up so that it returns directly 204 * to user mode to avoid stack copying and relocation problems. 205 */ 206 void 207 vm_forkproc(td, p2, td2, flags) 208 struct thread *td; 209 struct proc *p2; 210 struct thread *td2; 211 int flags; 212 { 213 struct proc *p1 = td->td_proc; 214 struct user *up; 215 216 GIANT_REQUIRED; 217 218 if ((flags & RFPROC) == 0) { 219 /* 220 * Divorce the memory, if it is shared, essentially 221 * this changes shared memory amongst threads, into 222 * COW locally. 223 */ 224 if ((flags & RFMEM) == 0) { 225 if (p1->p_vmspace->vm_refcnt > 1) { 226 vmspace_unshare(p1); 227 } 228 } 229 cpu_fork(td, p2, td2, flags); 230 return; 231 } 232 233 if (flags & RFMEM) { 234 p2->p_vmspace = p1->p_vmspace; 235 p1->p_vmspace->vm_refcnt++; 236 } 237 238 while (vm_page_count_severe()) { 239 VM_WAIT; 240 } 241 242 if ((flags & RFMEM) == 0) { 243 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 244 245 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 246 247 if (p1->p_vmspace->vm_shm) 248 shmfork(p1, p2); 249 } 250 251 pmap_new_proc(p2); 252 pmap_new_thread(td2); /* Initial thread */ 253 254 /* XXXKSE this is unsatisfactory but should be adequate */ 255 up = p2->p_uarea; 256 257 /* 258 * p_stats currently points at fields in the user struct 259 * but not at &u, instead at p_addr. Copy parts of 260 * p_stats; zero the rest of p_stats (statistics). 261 * 262 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 263 * to share sigacts, so we use the up->u_sigacts. 264 */ 265 p2->p_stats = &up->u_stats; 266 if (p2->p_sigacts == NULL) { 267 if (p2->p_procsig->ps_refcnt != 1) 268 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 269 p2->p_sigacts = &up->u_sigacts; 270 up->u_sigacts = *p1->p_sigacts; 271 } 272 273 bzero(&up->u_stats.pstat_startzero, 274 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 275 (caddr_t) &up->u_stats.pstat_startzero)); 276 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 277 ((caddr_t) &up->u_stats.pstat_endcopy - 278 (caddr_t) &up->u_stats.pstat_startcopy)); 279 280 281 /* 282 * cpu_fork will copy and update the pcb, set up the kernel stack, 283 * and make the child ready to run. 284 */ 285 cpu_fork(td, p2, td2, flags); 286 } 287 288 /* 289 * Called after process has been wait(2)'ed apon and is being reaped. 290 * The idea is to reclaim resources that we could not reclaim while 291 * the process was still executing. 292 */ 293 void 294 vm_waitproc(p) 295 struct proc *p; 296 { 297 struct thread *td; 298 299 GIANT_REQUIRED; 300 cpu_wait(p); 301 pmap_dispose_proc(p); /* drop per-process resources */ 302 FOREACH_THREAD_IN_PROC(p, td) 303 pmap_dispose_thread(td); 304 vmspace_exitfree(p); /* and clean-out the vmspace */ 305 } 306 307 /* 308 * Set default limits for VM system. 309 * Called for proc 0, and then inherited by all others. 310 * 311 * XXX should probably act directly on proc0. 312 */ 313 static void 314 vm_init_limits(udata) 315 void *udata; 316 { 317 struct proc *p = udata; 318 int rss_limit; 319 320 /* 321 * Set up the initial limits on process VM. Set the maximum resident 322 * set size to be half of (reasonably) available memory. Since this 323 * is a soft limit, it comes into effect only when the system is out 324 * of memory - half of main memory helps to favor smaller processes, 325 * and reduces thrashing of the object cache. 326 */ 327 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 328 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 329 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 330 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 331 /* limit the limit to no less than 2MB */ 332 rss_limit = max(cnt.v_free_count, 512); 333 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 334 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 335 } 336 337 void 338 faultin(p) 339 struct proc *p; 340 { 341 struct thread *td; 342 GIANT_REQUIRED; 343 344 PROC_LOCK_ASSERT(p, MA_OWNED); 345 mtx_lock_spin(&sched_lock); 346 if ((p->p_sflag & PS_INMEM) == 0) { 347 ++p->p_lock; 348 mtx_unlock_spin(&sched_lock); 349 PROC_UNLOCK(p); 350 351 pmap_swapin_proc(p); 352 FOREACH_THREAD_IN_PROC (p, td) 353 pmap_swapin_thread(td); 354 355 PROC_LOCK(p); 356 mtx_lock_spin(&sched_lock); 357 FOREACH_THREAD_IN_PROC (p, td) 358 if (td->td_proc->p_stat == SRUN) /* XXXKSE */ 359 setrunqueue(td); 360 361 p->p_sflag |= PS_INMEM; 362 363 /* undo the effect of setting SLOCK above */ 364 --p->p_lock; 365 } 366 mtx_unlock_spin(&sched_lock); 367 } 368 369 /* 370 * This swapin algorithm attempts to swap-in processes only if there 371 * is enough space for them. Of course, if a process waits for a long 372 * time, it will be swapped in anyway. 373 * 374 * XXXKSE - KSEGRP with highest priority counts.. 375 * 376 * Giant is still held at this point, to be released in tsleep. 377 */ 378 /* ARGSUSED*/ 379 static void 380 scheduler(dummy) 381 void *dummy; 382 { 383 struct proc *p; 384 int pri; 385 struct proc *pp; 386 int ppri; 387 388 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 389 /* GIANT_REQUIRED */ 390 391 loop: 392 if (vm_page_count_min()) { 393 VM_WAIT; 394 goto loop; 395 } 396 397 pp = NULL; 398 ppri = INT_MIN; 399 sx_slock(&allproc_lock); 400 FOREACH_PROC_IN_SYSTEM(p) { 401 struct ksegrp *kg; 402 mtx_lock_spin(&sched_lock); 403 if (p->p_stat == SRUN 404 && (p->p_sflag & (PS_INMEM | PS_SWAPPING)) == 0) { 405 /* Find the minimum sleeptime for the process */ 406 FOREACH_KSEGRP_IN_PROC(p, kg) { 407 pri = p->p_swtime + kg->kg_slptime; 408 if ((p->p_sflag & PS_SWAPINREQ) == 0) { 409 pri -= kg->kg_nice * 8; 410 } 411 412 /* 413 * if this ksegrp is higher priority 414 * and there is enough space, then select 415 * this process instead of the previous 416 * selection. 417 */ 418 if (pri > ppri) { 419 pp = p; 420 ppri = pri; 421 } 422 } 423 } 424 mtx_unlock_spin(&sched_lock); 425 } 426 sx_sunlock(&allproc_lock); 427 428 /* 429 * Nothing to do, back to sleep. 430 */ 431 if ((p = pp) == NULL) { 432 tsleep(&proc0, PVM, "sched", maxslp * hz / 2); 433 goto loop; 434 } 435 mtx_lock_spin(&sched_lock); 436 p->p_sflag &= ~PS_SWAPINREQ; 437 mtx_unlock_spin(&sched_lock); 438 439 /* 440 * We would like to bring someone in. (only if there is space). 441 */ 442 PROC_LOCK(p); 443 faultin(p); 444 PROC_UNLOCK(p); 445 mtx_lock_spin(&sched_lock); 446 p->p_swtime = 0; 447 mtx_unlock_spin(&sched_lock); 448 goto loop; 449 } 450 451 #ifndef NO_SWAPPING 452 453 /* 454 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 455 */ 456 static int swap_idle_threshold1 = 2; 457 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 458 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 459 460 /* 461 * Swap_idle_threshold2 is the time that a process can be idle before 462 * it will be swapped out, if idle swapping is enabled. 463 */ 464 static int swap_idle_threshold2 = 10; 465 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 466 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 467 468 /* 469 * Swapout is driven by the pageout daemon. Very simple, we find eligible 470 * procs and unwire their u-areas. We try to always "swap" at least one 471 * process in case we need the room for a swapin. 472 * If any procs have been sleeping/stopped for at least maxslp seconds, 473 * they are swapped. Else, we swap the longest-sleeping or stopped process, 474 * if any, otherwise the longest-resident process. 475 */ 476 void 477 swapout_procs(action) 478 int action; 479 { 480 struct proc *p; 481 struct ksegrp *kg; 482 struct proc *outp, *outp2; 483 int outpri, outpri2; 484 int didswap = 0; 485 486 GIANT_REQUIRED; 487 488 outp = outp2 = NULL; 489 outpri = outpri2 = INT_MIN; 490 retry: 491 sx_slock(&allproc_lock); 492 LIST_FOREACH(p, &allproc, p_list) { 493 struct vmspace *vm; 494 int minslptime = 100000; 495 496 PROC_LOCK(p); 497 if (p->p_lock != 0 || 498 (p->p_flag & (P_TRACED|P_SYSTEM|P_WEXIT)) != 0) { 499 PROC_UNLOCK(p); 500 continue; 501 } 502 /* 503 * only aiod changes vmspace, however it will be 504 * skipped because of the if statement above checking 505 * for P_SYSTEM 506 */ 507 vm = p->p_vmspace; 508 mtx_lock_spin(&sched_lock); 509 if ((p->p_sflag & (PS_INMEM|PS_SWAPPING)) != PS_INMEM) { 510 mtx_unlock_spin(&sched_lock); 511 PROC_UNLOCK(p); 512 continue; 513 } 514 515 switch (p->p_stat) { 516 default: 517 mtx_unlock_spin(&sched_lock); 518 PROC_UNLOCK(p); 519 continue; 520 521 case SSLEEP: 522 case SSTOP: 523 /* 524 * do not swapout a realtime process 525 * Check all the thread groups.. 526 */ 527 FOREACH_KSEGRP_IN_PROC(p, kg) { 528 if (PRI_IS_REALTIME(kg->kg_pri_class)) { 529 mtx_unlock_spin(&sched_lock); 530 PROC_UNLOCK(p); 531 goto nextproc; 532 } 533 534 /* 535 * Do not swapout a process waiting 536 * on a critical event of some kind. 537 * Also guarantee swap_idle_threshold1 538 * time in memory. 539 */ 540 if (((FIRST_THREAD_IN_PROC(p)->td_priority) < PSOCK) || 541 (kg->kg_slptime < swap_idle_threshold1)) { 542 mtx_unlock_spin(&sched_lock); 543 PROC_UNLOCK(p); 544 goto nextproc; 545 } 546 547 /* 548 * If the system is under memory stress, 549 * or if we are swapping 550 * idle processes >= swap_idle_threshold2, 551 * then swap the process out. 552 */ 553 if (((action & VM_SWAP_NORMAL) == 0) && 554 (((action & VM_SWAP_IDLE) == 0) || 555 (kg->kg_slptime < swap_idle_threshold2))) { 556 mtx_unlock_spin(&sched_lock); 557 PROC_UNLOCK(p); 558 goto nextproc; 559 } 560 if (minslptime > kg->kg_slptime) 561 minslptime = kg->kg_slptime; 562 } 563 564 mtx_unlock_spin(&sched_lock); 565 ++vm->vm_refcnt; 566 /* 567 * do not swapout a process that 568 * is waiting for VM 569 * data structures there is a 570 * possible deadlock. 571 */ 572 if (!vm_map_trylock(&vm->vm_map)) { 573 vmspace_free(vm); 574 PROC_UNLOCK(p); 575 goto nextproc; 576 } 577 vm_map_unlock(&vm->vm_map); 578 /* 579 * If the process has been asleep for awhile and had 580 * most of its pages taken away already, swap it out. 581 */ 582 if ((action & VM_SWAP_NORMAL) || 583 ((action & VM_SWAP_IDLE) && 584 (minslptime > swap_idle_threshold2))) { 585 sx_sunlock(&allproc_lock); 586 swapout(p); 587 vmspace_free(vm); 588 didswap++; 589 goto retry; 590 } 591 PROC_UNLOCK(p); 592 vmspace_free(vm); 593 } 594 nextproc: 595 continue; 596 } 597 sx_sunlock(&allproc_lock); 598 /* 599 * If we swapped something out, and another process needed memory, 600 * then wakeup the sched process. 601 */ 602 if (didswap) 603 wakeup(&proc0); 604 } 605 606 static void 607 swapout(p) 608 struct proc *p; 609 { 610 struct thread *td; 611 612 PROC_LOCK_ASSERT(p, MA_OWNED); 613 #if defined(SWAP_DEBUG) 614 printf("swapping out %d\n", p->p_pid); 615 #endif 616 ++p->p_stats->p_ru.ru_nswap; 617 /* 618 * remember the process resident count 619 */ 620 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 621 622 mtx_lock_spin(&sched_lock); 623 p->p_sflag &= ~PS_INMEM; 624 p->p_sflag |= PS_SWAPPING; 625 PROC_UNLOCK(p); 626 FOREACH_THREAD_IN_PROC (p, td) 627 if (td->td_proc->p_stat == SRUN) /* XXXKSE */ 628 remrunqueue(td); /* XXXKSE */ 629 mtx_unlock_spin(&sched_lock); 630 631 pmap_swapout_proc(p); 632 FOREACH_THREAD_IN_PROC(p, td) 633 pmap_swapout_thread(td); 634 635 mtx_lock_spin(&sched_lock); 636 p->p_sflag &= ~PS_SWAPPING; 637 p->p_swtime = 0; 638 mtx_unlock_spin(&sched_lock); 639 } 640 #endif /* !NO_SWAPPING */ 641