vm_glue.c revision 71610
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: head/sys/vm/vm_glue.c 71610 2001-01-25 01:38:09Z jhb $ 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 101static void vm_init_limits __P((void *)); 102SYSINIT(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 */ 109static void scheduler __P((void *)); 110SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 111 112 113static void swapout __P((struct proc *)); 114 115int 116kernacc(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 135int 136useracc(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 176void 177vslock(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 185void 186vsunlock(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 */ 202void 203vm_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 */ 283static void 284vm_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/* 308 * Must be called with the proc struc mutex held. 309 */ 310void 311faultin(p) 312 struct proc *p; 313{ 314 315 mtx_assert(&p->p_mtx, MA_OWNED); 316 mtx_enter(&sched_lock, MTX_SPIN); 317 if ((p->p_sflag & PS_INMEM) == 0) { 318 319 ++p->p_lock; 320 mtx_exit(&sched_lock, MTX_SPIN); 321 PROC_UNLOCK(p); 322 323 mtx_assert(&Giant, MA_OWNED); 324 pmap_swapin_proc(p); 325 326 PROC_LOCK(p); 327 mtx_enter(&sched_lock, MTX_SPIN); 328 if (p->p_stat == SRUN) { 329 setrunqueue(p); 330 } 331 332 p->p_sflag |= PS_INMEM; 333 334 /* undo the effect of setting SLOCK above */ 335 --p->p_lock; 336 } 337 mtx_exit(&sched_lock, MTX_SPIN); 338} 339 340/* 341 * This swapin algorithm attempts to swap-in processes only if there 342 * is enough space for them. Of course, if a process waits for a long 343 * time, it will be swapped in anyway. 344 * 345 * Giant is still held at this point, to be released in tsleep. 346 */ 347/* ARGSUSED*/ 348static void 349scheduler(dummy) 350 void *dummy; 351{ 352 register struct proc *p; 353 register int pri; 354 struct proc *pp; 355 int ppri; 356 357 mtx_assert(&Giant, MA_OWNED); 358 359loop: 360 if (vm_page_count_min()) { 361 VM_WAIT; 362 goto loop; 363 } 364 365 pp = NULL; 366 ppri = INT_MIN; 367 ALLPROC_LOCK(AP_SHARED); 368 LIST_FOREACH(p, &allproc, p_list) { 369 mtx_enter(&sched_lock, MTX_SPIN); 370 if (p->p_stat == SRUN && 371 (p->p_sflag & (PS_INMEM | PS_SWAPPING)) == 0) { 372 373 pri = p->p_swtime + p->p_slptime; 374 if ((p->p_sflag & PS_SWAPINREQ) == 0) { 375 pri -= p->p_nice * 8; 376 } 377 378 /* 379 * if this process is higher priority and there is 380 * enough space, then select this process instead of 381 * the previous selection. 382 */ 383 if (pri > ppri) { 384 pp = p; 385 ppri = pri; 386 } 387 } 388 mtx_exit(&sched_lock, MTX_SPIN); 389 } 390 ALLPROC_LOCK(AP_RELEASE); 391 392 /* 393 * Nothing to do, back to sleep. 394 */ 395 if ((p = pp) == NULL) { 396 tsleep(&proc0, PVM, "sched", 0); 397 goto loop; 398 } 399 mtx_enter(&sched_lock, MTX_SPIN); 400 p->p_sflag &= ~PS_SWAPINREQ; 401 mtx_exit(&sched_lock, MTX_SPIN); 402 403 /* 404 * We would like to bring someone in. (only if there is space). 405 */ 406 PROC_LOCK(p); 407 faultin(p); 408 PROC_UNLOCK(p); 409 mtx_enter(&sched_lock, MTX_SPIN); 410 p->p_swtime = 0; 411 mtx_exit(&sched_lock, MTX_SPIN); 412 goto loop; 413} 414 415#ifndef NO_SWAPPING 416 417/* 418 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 419 */ 420static int swap_idle_threshold1 = 2; 421SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 422 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 423 424/* 425 * Swap_idle_threshold2 is the time that a process can be idle before 426 * it will be swapped out, if idle swapping is enabled. 427 */ 428static int swap_idle_threshold2 = 10; 429SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 430 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 431 432/* 433 * Swapout is driven by the pageout daemon. Very simple, we find eligible 434 * procs and unwire their u-areas. We try to always "swap" at least one 435 * process in case we need the room for a swapin. 436 * If any procs have been sleeping/stopped for at least maxslp seconds, 437 * they are swapped. Else, we swap the longest-sleeping or stopped process, 438 * if any, otherwise the longest-resident process. 439 */ 440void 441swapout_procs(action) 442int action; 443{ 444 register struct proc *p; 445 struct proc *outp, *outp2; 446 int outpri, outpri2; 447 int didswap = 0; 448 449 outp = outp2 = NULL; 450 outpri = outpri2 = INT_MIN; 451 ALLPROC_LOCK(AP_SHARED); 452retry: 453 LIST_FOREACH(p, &allproc, p_list) { 454 struct vmspace *vm; 455 456 PROC_LOCK(p); 457 if (p->p_lock != 0 || 458 (p->p_flag & (P_TRACED|P_SYSTEM|P_WEXIT)) != 0) { 459 PROC_UNLOCK(p); 460 continue; 461 } 462 vm = p->p_vmspace; 463 PROC_UNLOCK(p); 464 mtx_enter(&sched_lock, MTX_SPIN); 465 if ((p->p_sflag & (PS_INMEM|PS_SWAPPING)) != PS_INMEM) { 466 mtx_exit(&sched_lock, MTX_SPIN); 467 continue; 468 } 469 470 switch (p->p_stat) { 471 default: 472 mtx_exit(&sched_lock, MTX_SPIN); 473 continue; 474 475 case SSLEEP: 476 case SSTOP: 477 /* 478 * do not swapout a realtime process 479 */ 480 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type)) { 481 mtx_exit(&sched_lock, MTX_SPIN); 482 continue; 483 } 484 485 /* 486 * Do not swapout a process waiting on a critical 487 * event of some kind. Also guarantee swap_idle_threshold1 488 * time in memory. 489 */ 490 if (((p->p_priority & 0x7f) < PSOCK) || 491 (p->p_slptime < swap_idle_threshold1)) { 492 mtx_exit(&sched_lock, MTX_SPIN); 493 continue; 494 } 495 496 /* 497 * If the system is under memory stress, or if we are swapping 498 * idle processes >= swap_idle_threshold2, then swap the process 499 * out. 500 */ 501 if (((action & VM_SWAP_NORMAL) == 0) && 502 (((action & VM_SWAP_IDLE) == 0) || 503 (p->p_slptime < swap_idle_threshold2))) { 504 mtx_exit(&sched_lock, MTX_SPIN); 505 continue; 506 } 507 mtx_exit(&sched_lock, MTX_SPIN); 508 509 ++vm->vm_refcnt; 510 /* 511 * do not swapout a process that is waiting for VM 512 * data structures there is a possible deadlock. 513 */ 514 if (lockmgr(&vm->vm_map.lock, 515 LK_EXCLUSIVE | LK_NOWAIT, 516 (void *)0, curproc)) { 517 vmspace_free(vm); 518 continue; 519 } 520 vm_map_unlock(&vm->vm_map); 521 /* 522 * If the process has been asleep for awhile and had 523 * most of its pages taken away already, swap it out. 524 */ 525 mtx_enter(&sched_lock, MTX_SPIN); 526 if ((action & VM_SWAP_NORMAL) || 527 ((action & VM_SWAP_IDLE) && 528 (p->p_slptime > swap_idle_threshold2))) { 529 mtx_exit(&sched_lock, MTX_SPIN); 530 swapout(p); 531 vmspace_free(vm); 532 didswap++; 533 goto retry; 534 } else 535 mtx_exit(&sched_lock, MTX_SPIN); 536 } 537 } 538 ALLPROC_LOCK(AP_RELEASE); 539 /* 540 * If we swapped something out, and another process needed memory, 541 * then wakeup the sched process. 542 */ 543 if (didswap) 544 wakeup(&proc0); 545} 546 547static void 548swapout(p) 549 register struct proc *p; 550{ 551 552#if defined(SWAP_DEBUG) 553 printf("swapping out %d\n", p->p_pid); 554#endif 555 ++p->p_stats->p_ru.ru_nswap; 556 /* 557 * remember the process resident count 558 */ 559 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 560 561 (void) splhigh(); 562 mtx_enter(&sched_lock, MTX_SPIN); 563 p->p_sflag &= ~PS_INMEM; 564 p->p_sflag |= PS_SWAPPING; 565 if (p->p_stat == SRUN) 566 remrunqueue(p); 567 mtx_exit(&sched_lock, MTX_SPIN); 568 (void) spl0(); 569 570 pmap_swapout_proc(p); 571 572 mtx_enter(&sched_lock, MTX_SPIN); 573 p->p_sflag &= ~PS_SWAPPING; 574 p->p_swtime = 0; 575 mtx_exit(&sched_lock, MTX_SPIN); 576} 577#endif /* !NO_SWAPPING */ 578