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 1.87 1999/07/21 18:02:26 alc 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 int 116 kernacc(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 = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 123 124 saddr = trunc_page((vm_offset_t)addr); 125 eaddr = round_page((vm_offset_t)addr + len); 126 vm_map_lock_read(kernel_map); 127 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 128 vm_map_unlock_read(kernel_map); 129 return (rv == TRUE); 130 } 131 132 int 133 useracc(addr, len, rw) 134 caddr_t addr; 135 int len, rw; 136 { 137 boolean_t rv; 138 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 139 vm_map_t map; 140 vm_map_entry_t save_hint; 141 142 /* 143 * XXX - check separately to disallow access to user area and user 144 * page tables - they are in the map. 145 * 146 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once 147 * only used (as an end address) in trap.c. Use it as an end address 148 * here too. This bogusness has spread. I just fixed where it was 149 * used as a max in vm_mmap.c. 150 */ 151 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS 152 || (vm_offset_t) addr + len < (vm_offset_t) addr) { 153 return (FALSE); 154 } 155 map = &curproc->p_vmspace->vm_map; 156 vm_map_lock_read(map); 157 /* 158 * We save the map hint, and restore it. Useracc appears to distort 159 * the map hint unnecessarily. 160 */ 161 save_hint = map->hint; 162 rv = vm_map_check_protection(map, 163 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot); 164 map->hint = save_hint; 165 vm_map_unlock_read(map); 166 167 return (rv == TRUE); 168 } 169 170 void 171 vslock(addr, len) 172 caddr_t addr; 173 u_int len; 174 { 175 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 176 round_page((vm_offset_t)addr + len), FALSE); 177 } 178 179 void 180 vsunlock(addr, len, dirtied) 181 caddr_t addr; 182 u_int len; 183 int dirtied; 184 { 185 #ifdef lint 186 dirtied++; 187 #endif /* lint */ 188 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 189 round_page((vm_offset_t)addr + len), TRUE); 190 } 191 192 /* 193 * Implement fork's actions on an address space. 194 * Here we arrange for the address space to be copied or referenced, 195 * allocate a user struct (pcb and kernel stack), then call the 196 * machine-dependent layer to fill those in and make the new process 197 * ready to run. The new process is set up so that it returns directly 198 * to user mode to avoid stack copying and relocation problems. 199 */ 200 void 201 vm_fork(p1, p2, flags) 202 register struct proc *p1, *p2; 203 int flags; 204 { 205 register struct user *up; 206 207 if (flags & RFMEM) { 208 p2->p_vmspace = p1->p_vmspace; 209 p1->p_vmspace->vm_refcnt++; 210 } 211 212 /* 213 * Great, so we have a memory-heavy process and the 214 * entire machine comes to a screaching halt because 215 * nobody can fork/exec anything. What we really need 216 * to do is fix the process swapper so it swaps out the right 217 * processes. 218 */ 219 #if 0 220 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 221 vm_pageout_deficit += (UPAGES + VM_INITIAL_PAGEIN); 222 VM_WAIT; 223 } 224 #endif 225 226 if ((flags & RFMEM) == 0) { 227 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 228 229 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 230 231 if (p1->p_vmspace->vm_shm) 232 shmfork(p1, p2); 233 } 234 235 pmap_new_proc(p2); 236 237 up = p2->p_addr; 238 239 /* 240 * p_stats currently points at fields in the user struct 241 * but not at &u, instead at p_addr. Copy parts of 242 * p_stats; zero the rest of p_stats (statistics). 243 * 244 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 245 * to share sigacts, so we use the up->u_sigacts. 246 */ 247 p2->p_stats = &up->u_stats; 248 if (p2->p_sigacts == NULL) { 249 if (p2->p_procsig->ps_refcnt != 1) 250 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 251 p2->p_sigacts = &up->u_sigacts; 252 up->u_sigacts = *p1->p_sigacts; 253 } 254 255 bzero(&up->u_stats.pstat_startzero, 256 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 257 (caddr_t) &up->u_stats.pstat_startzero)); 258 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 259 ((caddr_t) &up->u_stats.pstat_endcopy - 260 (caddr_t) &up->u_stats.pstat_startcopy)); 261 262 263 /* 264 * cpu_fork will copy and update the pcb, set up the kernel stack, 265 * and make the child ready to run. 266 */ 267 cpu_fork(p1, p2); 268 } 269 270 /* 271 * Set default limits for VM system. 272 * Called for proc 0, and then inherited by all others. 273 * 274 * XXX should probably act directly on proc0. 275 */ 276 static void 277 vm_init_limits(udata) 278 void *udata; 279 { 280 register struct proc *p = udata; 281 int rss_limit; 282 283 /* 284 * Set up the initial limits on process VM. Set the maximum resident 285 * set size to be half of (reasonably) available memory. Since this 286 * is a soft limit, it comes into effect only when the system is out 287 * of memory - half of main memory helps to favor smaller processes, 288 * and reduces thrashing of the object cache. 289 */ 290 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 291 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 292 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 293 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 294 /* limit the limit to no less than 2MB */ 295 rss_limit = max(cnt.v_free_count, 512); 296 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 297 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 298 } 299 300 void 301 faultin(p) 302 struct proc *p; 303 { 304 int s; 305 306 if ((p->p_flag & P_INMEM) == 0) { 307 308 ++p->p_lock; 309 310 pmap_swapin_proc(p); 311 312 s = splhigh(); 313 314 if (p->p_stat == SRUN) 315 setrunqueue(p); 316 317 p->p_flag |= P_INMEM; 318 319 /* undo the effect of setting SLOCK above */ 320 --p->p_lock; 321 splx(s); 322 323 } 324 } 325 326 /* 327 * This swapin algorithm attempts to swap-in processes only if there 328 * is enough space for them. Of course, if a process waits for a long 329 * time, it will be swapped in anyway. 330 */ 331 /* ARGSUSED*/ 332 static void 333 scheduler(dummy) 334 void *dummy; 335 { 336 register struct proc *p; 337 register int pri; 338 struct proc *pp; 339 int ppri; 340 341 loop: 342 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 343 VM_WAIT; 344 } 345 346 pp = NULL; 347 ppri = INT_MIN; 348 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 349 if (p->p_stat == SRUN && 350 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { 351 352 pri = p->p_swtime + p->p_slptime; 353 if ((p->p_flag & P_SWAPINREQ) == 0) { 354 pri -= p->p_nice * 8; 355 } 356 357 /* 358 * if this process is higher priority and there is 359 * enough space, then select this process instead of 360 * the previous selection. 361 */ 362 if (pri > ppri) { 363 pp = p; 364 ppri = pri; 365 } 366 } 367 } 368 369 /* 370 * Nothing to do, back to sleep. 371 */ 372 if ((p = pp) == NULL) { 373 tsleep(&proc0, PVM, "sched", 0); 374 goto loop; 375 } 376 p->p_flag &= ~P_SWAPINREQ; 377 378 /* 379 * We would like to bring someone in. (only if there is space). 380 */ 381 faultin(p); 382 p->p_swtime = 0; 383 goto loop; 384 } 385 386 #ifndef NO_SWAPPING 387 388 #define swappable(p) \ 389 (((p)->p_lock == 0) && \ 390 ((p)->p_flag & (P_TRACED|P_SYSTEM|P_INMEM|P_WEXIT|P_SWAPPING)) == P_INMEM) 391 392 393 /* 394 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 395 */ 396 static int swap_idle_threshold1 = 2; 397 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 398 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 399 400 /* 401 * Swap_idle_threshold2 is the time that a process can be idle before 402 * it will be swapped out, if idle swapping is enabled. 403 */ 404 static int swap_idle_threshold2 = 10; 405 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 406 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 407 408 /* 409 * Swapout is driven by the pageout daemon. Very simple, we find eligible 410 * procs and unwire their u-areas. We try to always "swap" at least one 411 * process in case we need the room for a swapin. 412 * If any procs have been sleeping/stopped for at least maxslp seconds, 413 * they are swapped. Else, we swap the longest-sleeping or stopped process, 414 * if any, otherwise the longest-resident process. 415 */ 416 void 417 swapout_procs(action) 418 int action; 419 { 420 register struct proc *p; 421 struct proc *outp, *outp2; 422 int outpri, outpri2; 423 int didswap = 0; 424 425 outp = outp2 = NULL; 426 outpri = outpri2 = INT_MIN; 427 retry: 428 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 429 struct vmspace *vm; 430 if (!swappable(p)) 431 continue; 432 433 vm = p->p_vmspace; 434 435 switch (p->p_stat) { 436 default: 437 continue; 438 439 case SSLEEP: 440 case SSTOP: 441 /* 442 * do not swapout a realtime process 443 */ 444 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type)) 445 continue; 446 447 /* 448 * Do not swapout a process waiting on a critical 449 * event of some kind. Also guarantee swap_idle_threshold1 450 * time in memory. 451 */ 452 if (((p->p_priority & 0x7f) < PSOCK) || 453 (p->p_slptime < swap_idle_threshold1)) 454 continue; 455 456 /* 457 * If the system is under memory stress, or if we are swapping 458 * idle processes >= swap_idle_threshold2, then swap the process 459 * out. 460 */ 461 if (((action & VM_SWAP_NORMAL) == 0) && 462 (((action & VM_SWAP_IDLE) == 0) || 463 (p->p_slptime < swap_idle_threshold2))) 464 continue; 465 466 ++vm->vm_refcnt; 467 /* 468 * do not swapout a process that is waiting for VM 469 * data structures there is a possible deadlock. 470 */ 471 if (lockmgr(&vm->vm_map.lock, 472 LK_EXCLUSIVE | LK_NOWAIT, 473 (void *)0, curproc)) { 474 vmspace_free(vm); 475 continue; 476 } 477 vm_map_unlock(&vm->vm_map); 478 /* 479 * If the process has been asleep for awhile and had 480 * most of its pages taken away already, swap it out. 481 */ 482 if ((action & VM_SWAP_NORMAL) || 483 ((action & VM_SWAP_IDLE) && 484 (p->p_slptime > swap_idle_threshold2))) { 485 swapout(p); 486 vmspace_free(vm); 487 didswap++; 488 goto retry; 489 } 490 } 491 } 492 /* 493 * If we swapped something out, and another process needed memory, 494 * then wakeup the sched process. 495 */ 496 if (didswap) 497 wakeup(&proc0); 498 } 499 500 static void 501 swapout(p) 502 register struct proc *p; 503 { 504 505 #if defined(SWAP_DEBUG) 506 printf("swapping out %d\n", p->p_pid); 507 #endif 508 ++p->p_stats->p_ru.ru_nswap; 509 /* 510 * remember the process resident count 511 */ 512 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 513 514 (void) splhigh(); 515 p->p_flag &= ~P_INMEM; 516 p->p_flag |= P_SWAPPING; 517 if (p->p_stat == SRUN) 518 remrunqueue(p); 519 (void) spl0(); 520 521 pmap_swapout_proc(p); 522 523 p->p_flag &= ~P_SWAPPING; 524 p->p_swtime = 0; 525 } 526 #endif /* !NO_SWAPPING */ 527