vm_glue.c revision 44146
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 * $Id: vm_glue.c,v 1.83 1999/01/26 02:38:12 julian Exp $ 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 <vm/vm_prot.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 115extern char kstack[]; 116 117/* vm_map_t upages_map; */ 118 119int 120kernacc(addr, len, rw) 121 caddr_t addr; 122 int len, rw; 123{ 124 boolean_t rv; 125 vm_offset_t saddr, eaddr; 126 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 127 128 saddr = trunc_page((vm_offset_t)addr); 129 eaddr = round_page((vm_offset_t)addr + len); 130 vm_map_lock_read(kernel_map); 131 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 132 vm_map_unlock_read(kernel_map); 133 return (rv == TRUE); 134} 135 136int 137useracc(addr, len, rw) 138 caddr_t addr; 139 int len, rw; 140{ 141 boolean_t rv; 142 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 143 vm_map_t map; 144 vm_map_entry_t save_hint; 145 146 /* 147 * XXX - check separately to disallow access to user area and user 148 * page tables - they are in the map. 149 * 150 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once 151 * only used (as an end address) in trap.c. Use it as an end address 152 * here too. This bogusness has spread. I just fixed where it was 153 * used as a max in vm_mmap.c. 154 */ 155 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS 156 || (vm_offset_t) addr + len < (vm_offset_t) addr) { 157 return (FALSE); 158 } 159 map = &curproc->p_vmspace->vm_map; 160 vm_map_lock_read(map); 161 /* 162 * We save the map hint, and restore it. Useracc appears to distort 163 * the map hint unnecessarily. 164 */ 165 save_hint = map->hint; 166 rv = vm_map_check_protection(map, 167 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot); 168 map->hint = save_hint; 169 vm_map_unlock_read(map); 170 171 return (rv == TRUE); 172} 173 174void 175vslock(addr, len) 176 caddr_t addr; 177 u_int len; 178{ 179 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 180 round_page((vm_offset_t)addr + len), FALSE); 181} 182 183void 184vsunlock(addr, len, dirtied) 185 caddr_t addr; 186 u_int len; 187 int dirtied; 188{ 189#ifdef lint 190 dirtied++; 191#endif /* lint */ 192 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 193 round_page((vm_offset_t)addr + len), TRUE); 194} 195 196/* 197 * Implement fork's actions on an address space. 198 * Here we arrange for the address space to be copied or referenced, 199 * allocate a user struct (pcb and kernel stack), then call the 200 * machine-dependent layer to fill those in and make the new process 201 * ready to run. The new process is set up so that it returns directly 202 * to user mode to avoid stack copying and relocation problems. 203 */ 204void 205vm_fork(p1, p2, flags) 206 register struct proc *p1, *p2; 207 int flags; 208{ 209 register struct user *up; 210 211 if (flags & RFMEM) { 212 p2->p_vmspace = p1->p_vmspace; 213 p1->p_vmspace->vm_refcnt++; 214 } 215 216 /* 217 * Great, so we have a memory-heavy process and the 218 * entire machine comes to a screaching halt because 219 * nobody can fork/exec anything. What we really need 220 * to do is fix the process swapper so it swaps out the right 221 * processes. 222 */ 223#if 0 224 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 225 vm_pageout_deficit += (UPAGES + VM_INITIAL_PAGEIN); 226 VM_WAIT; 227 } 228#endif 229 230 if ((flags & RFMEM) == 0) { 231 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 232 233 if (p1->p_vmspace->vm_shm) 234 shmfork(p1, p2); 235 } 236 237 pmap_new_proc(p2); 238 239 up = p2->p_addr; 240 241 /* 242 * p_stats currently points at fields in the user struct 243 * but not at &u, instead at p_addr. Copy parts of 244 * p_stats; zero the rest of p_stats (statistics). 245 * 246 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 247 * to share sigacts, so we use the up->u_sigacts. 248 */ 249 p2->p_stats = &up->u_stats; 250 if (p2->p_sigacts == NULL) { 251 if (p2->p_procsig->ps_refcnt != 1) 252 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 253 p2->p_sigacts = &up->u_sigacts; 254 up->u_sigacts = *p1->p_sigacts; 255 } 256 257 bzero(&up->u_stats.pstat_startzero, 258 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 259 (caddr_t) &up->u_stats.pstat_startzero)); 260 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 261 ((caddr_t) &up->u_stats.pstat_endcopy - 262 (caddr_t) &up->u_stats.pstat_startcopy)); 263 264 265 /* 266 * cpu_fork will copy and update the pcb, set up the kernel stack, 267 * and make the child ready to run. 268 */ 269 cpu_fork(p1, p2); 270} 271 272/* 273 * Set default limits for VM system. 274 * Called for proc 0, and then inherited by all others. 275 * 276 * XXX should probably act directly on proc0. 277 */ 278static void 279vm_init_limits(udata) 280 void *udata; 281{ 282 register struct proc *p = udata; 283 int rss_limit; 284 285 /* 286 * Set up the initial limits on process VM. Set the maximum resident 287 * set size to be half of (reasonably) available memory. Since this 288 * is a soft limit, it comes into effect only when the system is out 289 * of memory - half of main memory helps to favor smaller processes, 290 * and reduces thrashing of the object cache. 291 */ 292 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 293 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 294 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 295 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 296 /* limit the limit to no less than 2MB */ 297 rss_limit = max(cnt.v_free_count, 512); 298 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 299 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 300} 301 302void 303faultin(p) 304 struct proc *p; 305{ 306 int s; 307 308 if ((p->p_flag & P_INMEM) == 0) { 309 310 ++p->p_lock; 311 312 pmap_swapin_proc(p); 313 314 s = splhigh(); 315 316 if (p->p_stat == SRUN) 317 setrunqueue(p); 318 319 p->p_flag |= P_INMEM; 320 321 /* undo the effect of setting SLOCK above */ 322 --p->p_lock; 323 splx(s); 324 325 } 326} 327 328/* 329 * This swapin algorithm attempts to swap-in processes only if there 330 * is enough space for them. Of course, if a process waits for a long 331 * time, it will be swapped in anyway. 332 */ 333/* ARGSUSED*/ 334static void 335scheduler(dummy) 336 void *dummy; 337{ 338 register struct proc *p; 339 register int pri; 340 struct proc *pp; 341 int ppri; 342 343loop: 344 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 345 VM_WAIT; 346 } 347 348 pp = NULL; 349 ppri = INT_MIN; 350 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 351 if (p->p_stat == SRUN && 352 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { 353 354 pri = p->p_swtime + p->p_slptime; 355 if ((p->p_flag & P_SWAPINREQ) == 0) { 356 pri -= p->p_nice * 8; 357 } 358 359 /* 360 * if this process is higher priority and there is 361 * enough space, then select this process instead of 362 * the previous selection. 363 */ 364 if (pri > ppri) { 365 pp = p; 366 ppri = pri; 367 } 368 } 369 } 370 371 /* 372 * Nothing to do, back to sleep. 373 */ 374 if ((p = pp) == NULL) { 375 tsleep(&proc0, PVM, "sched", 0); 376 goto loop; 377 } 378 p->p_flag &= ~P_SWAPINREQ; 379 380 /* 381 * We would like to bring someone in. (only if there is space). 382 */ 383 faultin(p); 384 p->p_swtime = 0; 385 goto loop; 386} 387 388#ifndef NO_SWAPPING 389 390#define swappable(p) \ 391 (((p)->p_lock == 0) && \ 392 ((p)->p_flag & (P_TRACED|P_NOSWAP|P_SYSTEM|P_INMEM|P_WEXIT|P_PHYSIO|P_SWAPPING)) == P_INMEM) 393 394 395/* 396 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 397 */ 398static int swap_idle_threshold1 = 2; 399SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 400 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 401 402/* 403 * Swap_idle_threshold2 is the time that a process can be idle before 404 * it will be swapped out, if idle swapping is enabled. 405 */ 406static int swap_idle_threshold2 = 10; 407SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 408 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 409 410/* 411 * Swapout is driven by the pageout daemon. Very simple, we find eligible 412 * procs and unwire their u-areas. We try to always "swap" at least one 413 * process in case we need the room for a swapin. 414 * If any procs have been sleeping/stopped for at least maxslp seconds, 415 * they are swapped. Else, we swap the longest-sleeping or stopped process, 416 * if any, otherwise the longest-resident process. 417 */ 418void 419swapout_procs(action) 420int action; 421{ 422 register struct proc *p; 423 struct proc *outp, *outp2; 424 int outpri, outpri2; 425 int didswap = 0; 426 427 outp = outp2 = NULL; 428 outpri = outpri2 = INT_MIN; 429retry: 430 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 431 struct vmspace *vm; 432 if (!swappable(p)) 433 continue; 434 435 vm = p->p_vmspace; 436 437 switch (p->p_stat) { 438 default: 439 continue; 440 441 case SSLEEP: 442 case SSTOP: 443 /* 444 * do not swapout a realtime process 445 */ 446 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type)) 447 continue; 448 449 /* 450 * Do not swapout a process waiting on a critical 451 * event of some kind. Also guarantee swap_idle_threshold1 452 * time in memory. 453 */ 454 if (((p->p_priority & 0x7f) < PSOCK) || 455 (p->p_slptime < swap_idle_threshold1)) 456 continue; 457 458 /* 459 * If the system is under memory stress, or if we are swapping 460 * idle processes >= swap_idle_threshold2, then swap the process 461 * out. 462 */ 463 if (((action & VM_SWAP_NORMAL) == 0) && 464 (((action & VM_SWAP_IDLE) == 0) || 465 (p->p_slptime < swap_idle_threshold2))) 466 continue; 467 468 ++vm->vm_refcnt; 469 /* 470 * do not swapout a process that is waiting for VM 471 * data structures there is a possible deadlock. 472 */ 473 if (lockmgr(&vm->vm_map.lock, 474 LK_EXCLUSIVE | LK_NOWAIT, 475 (void *)0, curproc)) { 476 vmspace_free(vm); 477 continue; 478 } 479 vm_map_unlock(&vm->vm_map); 480 /* 481 * If the process has been asleep for awhile and had 482 * most of its pages taken away already, swap it out. 483 */ 484 if ((action & VM_SWAP_NORMAL) || 485 ((action & VM_SWAP_IDLE) && 486 (p->p_slptime > swap_idle_threshold2))) { 487 swapout(p); 488 vmspace_free(vm); 489 didswap++; 490 goto retry; 491 } 492 } 493 } 494 /* 495 * If we swapped something out, and another process needed memory, 496 * then wakeup the sched process. 497 */ 498 if (didswap) 499 wakeup(&proc0); 500} 501 502static void 503swapout(p) 504 register struct proc *p; 505{ 506 507#if defined(SWAP_DEBUG) 508 printf("swapping out %d\n", p->p_pid); 509#endif 510 ++p->p_stats->p_ru.ru_nswap; 511 /* 512 * remember the process resident count 513 */ 514 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 515 516 (void) splhigh(); 517 p->p_flag &= ~P_INMEM; 518 p->p_flag |= P_SWAPPING; 519 if (p->p_stat == SRUN) 520 remrq(p); 521 (void) spl0(); 522 523 pmap_swapout_proc(p); 524 525 p->p_flag &= ~P_SWAPPING; 526 p->p_swtime = 0; 527} 528#endif /* !NO_SWAPPING */ 529