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