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 1.79 1998/12/19 08:23:31 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 */ 100 101 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 extern char kstack[]; 116 117 /* vm_map_t upages_map; */ 118 119 int 120 kernacc(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 } 135 136 int 137 useracc(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 } 173 174 void 175 vslock(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 } 182 183 void 184 vsunlock(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 */ 204 void 205 vm_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 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 217 vm_pageout_deficit += (UPAGES + VM_INITIAL_PAGEIN); 218 VM_WAIT; 219 } 220 221 if ((flags & RFMEM) == 0) { 222 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 223 224 if (p1->p_vmspace->vm_shm) 225 shmfork(p1, p2); 226 } 227 228 pmap_new_proc(p2); 229 230 up = p2->p_addr; 231 232 #ifndef COMPAT_LINUX_THREADS 233 /* 234 * p_stats and p_sigacts currently point at fields in the user struct 235 * but not at &u, instead at p_addr. Copy p_sigacts and parts of 236 * p_stats; zero the rest of p_stats (statistics). 237 */ 238 p2->p_stats = &up->u_stats; 239 p2->p_sigacts = &up->u_sigacts; 240 up->u_sigacts = *p1->p_sigacts; 241 #else 242 /* 243 * p_stats currently points at fields in the user struct 244 * but not at &u, instead at p_addr. Copy parts of 245 * p_stats; zero the rest of p_stats (statistics). 246 * 247 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 248 * to share sigacts, so we use the up->u_sigacts. 249 */ 250 p2->p_stats = &up->u_stats; 251 if (p2->p_sigacts == NULL) { 252 if (p2->p_procsig->ps_refcnt != 1) 253 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 254 p2->p_sigacts = &up->u_sigacts; 255 up->u_sigacts = *p1->p_sigacts; 256 } 257 #endif /* COMPAT_LINUX_THREADS */ 258 bzero(&up->u_stats.pstat_startzero, 259 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 260 (caddr_t) &up->u_stats.pstat_startzero)); 261 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 262 ((caddr_t) &up->u_stats.pstat_endcopy - 263 (caddr_t) &up->u_stats.pstat_startcopy)); 264 265 266 /* 267 * cpu_fork will copy and update the pcb, set up the kernel stack, 268 * and make the child ready to run. 269 */ 270 cpu_fork(p1, p2); 271 } 272 273 /* 274 * Set default limits for VM system. 275 * Called for proc 0, and then inherited by all others. 276 * 277 * XXX should probably act directly on proc0. 278 */ 279 static void 280 vm_init_limits(udata) 281 void *udata; 282 { 283 register struct proc *p = udata; 284 int rss_limit; 285 286 /* 287 * Set up the initial limits on process VM. Set the maximum resident 288 * set size to be half of (reasonably) available memory. Since this 289 * is a soft limit, it comes into effect only when the system is out 290 * of memory - half of main memory helps to favor smaller processes, 291 * and reduces thrashing of the object cache. 292 */ 293 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 294 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 295 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 296 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 297 /* limit the limit to no less than 2MB */ 298 rss_limit = max(cnt.v_free_count, 512); 299 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 300 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 301 } 302 303 void 304 faultin(p) 305 struct proc *p; 306 { 307 int s; 308 309 if ((p->p_flag & P_INMEM) == 0) { 310 311 ++p->p_lock; 312 313 pmap_swapin_proc(p); 314 315 s = splhigh(); 316 317 if (p->p_stat == SRUN) 318 setrunqueue(p); 319 320 p->p_flag |= P_INMEM; 321 322 /* undo the effect of setting SLOCK above */ 323 --p->p_lock; 324 splx(s); 325 326 } 327 } 328 329 /* 330 * This swapin algorithm attempts to swap-in processes only if there 331 * is enough space for them. Of course, if a process waits for a long 332 * time, it will be swapped in anyway. 333 */ 334 /* ARGSUSED*/ 335 static void 336 scheduler(dummy) 337 void *dummy; 338 { 339 register struct proc *p; 340 register int pri; 341 struct proc *pp; 342 int ppri; 343 344 loop: 345 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 346 VM_WAIT; 347 } 348 349 pp = NULL; 350 ppri = INT_MIN; 351 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 352 if (p->p_stat == SRUN && 353 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { 354 355 pri = p->p_swtime + p->p_slptime; 356 if ((p->p_flag & P_SWAPINREQ) == 0) { 357 pri -= p->p_nice * 8; 358 } 359 360 /* 361 * if this process is higher priority and there is 362 * enough space, then select this process instead of 363 * the previous selection. 364 */ 365 if (pri > ppri) { 366 pp = p; 367 ppri = pri; 368 } 369 } 370 } 371 372 /* 373 * Nothing to do, back to sleep. 374 */ 375 if ((p = pp) == NULL) { 376 tsleep(&proc0, PVM, "sched", 0); 377 goto loop; 378 } 379 p->p_flag &= ~P_SWAPINREQ; 380 381 /* 382 * We would like to bring someone in. (only if there is space). 383 */ 384 faultin(p); 385 p->p_swtime = 0; 386 goto loop; 387 } 388 389 #ifndef NO_SWAPPING 390 391 #define swappable(p) \ 392 (((p)->p_lock == 0) && \ 393 ((p)->p_flag & (P_TRACED|P_NOSWAP|P_SYSTEM|P_INMEM|P_WEXIT|P_PHYSIO|P_SWAPPING)) == P_INMEM) 394 395 396 /* 397 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 398 */ 399 static int swap_idle_threshold1 = 2; 400 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 401 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 402 403 /* 404 * Swap_idle_threshold2 is the time that a process can be idle before 405 * it will be swapped out, if idle swapping is enabled. 406 */ 407 static int swap_idle_threshold2 = 10; 408 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 409 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 410 411 /* 412 * Swapout is driven by the pageout daemon. Very simple, we find eligible 413 * procs and unwire their u-areas. We try to always "swap" at least one 414 * process in case we need the room for a swapin. 415 * If any procs have been sleeping/stopped for at least maxslp seconds, 416 * they are swapped. Else, we swap the longest-sleeping or stopped process, 417 * if any, otherwise the longest-resident process. 418 */ 419 void 420 swapout_procs(action) 421 int action; 422 { 423 register struct proc *p; 424 struct proc *outp, *outp2; 425 int outpri, outpri2; 426 int didswap = 0; 427 428 outp = outp2 = NULL; 429 outpri = outpri2 = INT_MIN; 430 retry: 431 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 432 struct vmspace *vm; 433 if (!swappable(p)) 434 continue; 435 436 vm = p->p_vmspace; 437 438 switch (p->p_stat) { 439 default: 440 continue; 441 442 case SSLEEP: 443 case SSTOP: 444 /* 445 * do not swapout a realtime process 446 */ 447 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type)) 448 continue; 449 450 /* 451 * Do not swapout a process waiting on a critical 452 * event of some kind. Also guarantee swap_idle_threshold1 453 * time in memory. 454 */ 455 if (((p->p_priority & 0x7f) < PSOCK) || 456 (p->p_slptime < swap_idle_threshold1)) 457 continue; 458 459 /* 460 * If the system is under memory stress, or if we are swapping 461 * idle processes >= swap_idle_threshold2, then swap the process 462 * out. 463 */ 464 if (((action & VM_SWAP_NORMAL) == 0) && 465 (((action & VM_SWAP_IDLE) == 0) || 466 (p->p_slptime < swap_idle_threshold2))) 467 continue; 468 469 ++vm->vm_refcnt; 470 /* 471 * do not swapout a process that is waiting for VM 472 * data structures there is a possible deadlock. 473 */ 474 if (lockmgr(&vm->vm_map.lock, 475 LK_EXCLUSIVE | LK_NOWAIT, 476 (void *)0, curproc)) { 477 vmspace_free(vm); 478 continue; 479 } 480 vm_map_unlock(&vm->vm_map); 481 /* 482 * If the process has been asleep for awhile and had 483 * most of its pages taken away already, swap it out. 484 */ 485 if ((action & VM_SWAP_NORMAL) || 486 ((action & VM_SWAP_IDLE) && 487 (p->p_slptime > swap_idle_threshold2))) { 488 swapout(p); 489 vmspace_free(vm); 490 didswap++; 491 goto retry; 492 } 493 } 494 } 495 /* 496 * If we swapped something out, and another process needed memory, 497 * then wakeup the sched process. 498 */ 499 if (didswap) 500 wakeup(&proc0); 501 } 502 503 static void 504 swapout(p) 505 register struct proc *p; 506 { 507 508 #if defined(SWAP_DEBUG) 509 printf("swapping out %d\n", p->p_pid); 510 #endif 511 ++p->p_stats->p_ru.ru_nswap; 512 /* 513 * remember the process resident count 514 */ 515 p->p_vmspace->vm_swrss = 516 p->p_vmspace->vm_pmap.pm_stats.resident_count; 517 518 (void) splhigh(); 519 p->p_flag &= ~P_INMEM; 520 p->p_flag |= P_SWAPPING; 521 if (p->p_stat == SRUN) 522 remrq(p); 523 (void) spl0(); 524 525 pmap_swapout_proc(p); 526 527 p->p_flag &= ~P_SWAPPING; 528 p->p_swtime = 0; 529 } 530 #endif /* !NO_SWAPPING */ 531