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_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/unistd.h> 78 79 #include <machine/limits.h> 80 81 #include <vm/vm.h> 82 #include <vm/vm_param.h> 83 #include <sys/lock.h> 84 #include <vm/pmap.h> 85 #include <vm/vm_map.h> 86 #include <vm/vm_page.h> 87 #include <vm/vm_pageout.h> 88 #include <vm/vm_kern.h> 89 #include <vm/vm_extern.h> 90 91 #include <sys/user.h> 92 93 /* 94 * System initialization 95 * 96 * Note: proc0 from proc.h 97 */ 98 99 static void vm_init_limits __P((void *)); 100 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) 101 102 /* 103 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 104 * 105 * Note: run scheduling should be divorced from the vm system. 106 */ 107 static void scheduler __P((void *)); 108 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 109 110 111 static void swapout __P((struct proc *)); 112 113 int 114 kernacc(addr, len, rw) 115 caddr_t addr; 116 int len, rw; 117 { 118 boolean_t rv; 119 vm_offset_t saddr, eaddr; 120 vm_prot_t prot; 121 122 KASSERT((rw & (~VM_PROT_ALL)) == 0, 123 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 124 prot = rw; 125 saddr = trunc_page((vm_offset_t)addr); 126 eaddr = round_page((vm_offset_t)addr + len); 127 vm_map_lock_read(kernel_map); 128 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 129 vm_map_unlock_read(kernel_map); 130 return (rv == TRUE); 131 } 132 133 int 134 useracc(addr, len, rw) 135 caddr_t addr; 136 int len, rw; 137 { 138 boolean_t rv; 139 vm_prot_t prot; 140 vm_map_t map; 141 vm_map_entry_t save_hint; 142 143 KASSERT((rw & (~VM_PROT_ALL)) == 0, 144 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 145 prot = rw; 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) 185 caddr_t addr; 186 u_int len; 187 { 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 & RFPROC) == 0) { 208 /* 209 * Divorce the memory, if it is shared, essentially 210 * this changes shared memory amongst threads, into 211 * COW locally. 212 */ 213 if ((flags & RFMEM) == 0) { 214 if (p1->p_vmspace->vm_refcnt > 1) { 215 vmspace_unshare(p1); 216 } 217 } 218 cpu_fork(p1, p2, flags); 219 return; 220 } 221 222 if (flags & RFMEM) { 223 p2->p_vmspace = p1->p_vmspace; 224 p1->p_vmspace->vm_refcnt++; 225 } 226 227 while (vm_page_count_severe()) { 228 VM_WAIT; 229 } 230 231 if ((flags & RFMEM) == 0) { 232 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 233 234 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 235 236 if (p1->p_vmspace->vm_shm) 237 shmfork(p1, p2); 238 } 239 240 pmap_new_proc(p2); 241 242 up = p2->p_addr; 243 244 /* 245 * p_stats currently points at fields in the user struct 246 * but not at &u, instead at p_addr. Copy parts of 247 * p_stats; zero the rest of p_stats (statistics). 248 * 249 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 250 * to share sigacts, so we use the up->u_sigacts. 251 */ 252 p2->p_stats = &up->u_stats; 253 if (p2->p_sigacts == NULL) { 254 if (p2->p_procsig->ps_refcnt != 1) 255 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 256 p2->p_sigacts = &up->u_sigacts; 257 up->u_sigacts = *p1->p_sigacts; 258 } 259 260 bzero(&up->u_stats.pstat_startzero, 261 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 262 (caddr_t) &up->u_stats.pstat_startzero)); 263 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 264 ((caddr_t) &up->u_stats.pstat_endcopy - 265 (caddr_t) &up->u_stats.pstat_startcopy)); 266 267 268 /* 269 * cpu_fork will copy and update the pcb, set up the kernel stack, 270 * and make the child ready to run. 271 */ 272 cpu_fork(p1, p2, flags); 273 } 274 275 /* 276 * Set default limits for VM system. 277 * Called for proc 0, and then inherited by all others. 278 * 279 * XXX should probably act directly on proc0. 280 */ 281 static void 282 vm_init_limits(udata) 283 void *udata; 284 { 285 register struct proc *p = udata; 286 int rss_limit; 287 288 /* 289 * Set up the initial limits on process VM. Set the maximum resident 290 * set size to be half of (reasonably) available memory. Since this 291 * is a soft limit, it comes into effect only when the system is out 292 * of memory - half of main memory helps to favor smaller processes, 293 * and reduces thrashing of the object cache. 294 */ 295 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 296 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 297 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 298 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 299 /* limit the limit to no less than 2MB */ 300 rss_limit = max(cnt.v_free_count, 512); 301 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 302 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 303 } 304 305 void 306 faultin(p) 307 struct proc *p; 308 { 309 int s; 310 311 if ((p->p_flag & P_INMEM) == 0) { 312 313 ++p->p_lock; 314 315 pmap_swapin_proc(p); 316 317 s = splhigh(); 318 319 if (p->p_stat == SRUN) 320 setrunqueue(p); 321 322 p->p_flag |= P_INMEM; 323 324 /* undo the effect of setting SLOCK above */ 325 --p->p_lock; 326 splx(s); 327 328 } 329 } 330 331 /* 332 * This swapin algorithm attempts to swap-in processes only if there 333 * is enough space for them. Of course, if a process waits for a long 334 * time, it will be swapped in anyway. 335 */ 336 /* ARGSUSED*/ 337 static void 338 scheduler(dummy) 339 void *dummy; 340 { 341 register struct proc *p; 342 register int pri; 343 struct proc *pp; 344 int ppri; 345 346 loop: 347 if (vm_page_count_min()) { 348 VM_WAIT; 349 goto loop; 350 } 351 352 pp = NULL; 353 ppri = INT_MIN; 354 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 355 if (p->p_stat == SRUN && 356 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { 357 358 pri = p->p_swtime + p->p_slptime; 359 if ((p->p_flag & P_SWAPINREQ) == 0) { 360 pri -= p->p_nice * 8; 361 } 362 363 /* 364 * if this process is higher priority and there is 365 * enough space, then select this process instead of 366 * the previous selection. 367 */ 368 if (pri > ppri) { 369 pp = p; 370 ppri = pri; 371 } 372 } 373 } 374 375 /* 376 * Nothing to do, back to sleep. 377 */ 378 if ((p = pp) == NULL) { 379 tsleep(&proc0, PVM, "sched", 0); 380 goto loop; 381 } 382 p->p_flag &= ~P_SWAPINREQ; 383 384 /* 385 * We would like to bring someone in. (only if there is space). 386 */ 387 faultin(p); 388 p->p_swtime = 0; 389 goto loop; 390 } 391 392 #ifndef NO_SWAPPING 393 394 #define swappable(p) \ 395 (((p)->p_lock == 0) && \ 396 ((p)->p_flag & (P_TRACED|P_SYSTEM|P_INMEM|P_WEXIT|P_SWAPPING)) == P_INMEM) 397 398 399 /* 400 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 401 */ 402 static int swap_idle_threshold1 = 2; 403 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 404 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 405 406 /* 407 * Swap_idle_threshold2 is the time that a process can be idle before 408 * it will be swapped out, if idle swapping is enabled. 409 */ 410 static int swap_idle_threshold2 = 10; 411 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 412 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 413 414 /* 415 * Swapout is driven by the pageout daemon. Very simple, we find eligible 416 * procs and unwire their u-areas. We try to always "swap" at least one 417 * process in case we need the room for a swapin. 418 * If any procs have been sleeping/stopped for at least maxslp seconds, 419 * they are swapped. Else, we swap the longest-sleeping or stopped process, 420 * if any, otherwise the longest-resident process. 421 */ 422 void 423 swapout_procs(action) 424 int action; 425 { 426 register struct proc *p; 427 struct proc *outp, *outp2; 428 int outpri, outpri2; 429 int didswap = 0; 430 431 outp = outp2 = NULL; 432 outpri = outpri2 = INT_MIN; 433 retry: 434 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 435 struct vmspace *vm; 436 if (!swappable(p)) 437 continue; 438 439 vm = p->p_vmspace; 440 441 switch (p->p_stat) { 442 default: 443 continue; 444 445 case SSLEEP: 446 case SSTOP: 447 /* 448 * do not swapout a realtime process 449 */ 450 if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type)) 451 continue; 452 453 /* 454 * Do not swapout a process waiting on a critical 455 * event of some kind. Also guarantee swap_idle_threshold1 456 * time in memory. 457 */ 458 if (((p->p_priority & 0x7f) < PSOCK) || 459 (p->p_slptime < swap_idle_threshold1)) 460 continue; 461 462 /* 463 * If the system is under memory stress, or if we are swapping 464 * idle processes >= swap_idle_threshold2, then swap the process 465 * out. 466 */ 467 if (((action & VM_SWAP_NORMAL) == 0) && 468 (((action & VM_SWAP_IDLE) == 0) || 469 (p->p_slptime < swap_idle_threshold2))) 470 continue; 471 472 ++vm->vm_refcnt; 473 /* 474 * do not swapout a process that is waiting for VM 475 * data structures there is a possible deadlock. 476 */ 477 if (lockmgr(&vm->vm_map.lock, 478 LK_EXCLUSIVE | LK_NOWAIT, 479 (void *)0, curproc)) { 480 vmspace_free(vm); 481 continue; 482 } 483 vm_map_unlock(&vm->vm_map); 484 /* 485 * If the process has been asleep for awhile and had 486 * most of its pages taken away already, swap it out. 487 */ 488 if ((action & VM_SWAP_NORMAL) || 489 ((action & VM_SWAP_IDLE) && 490 (p->p_slptime > swap_idle_threshold2))) { 491 swapout(p); 492 vmspace_free(vm); 493 didswap++; 494 goto retry; 495 } 496 } 497 } 498 /* 499 * If we swapped something out, and another process needed memory, 500 * then wakeup the sched process. 501 */ 502 if (didswap) 503 wakeup(&proc0); 504 } 505 506 static void 507 swapout(p) 508 register struct proc *p; 509 { 510 511 #if defined(SWAP_DEBUG) 512 printf("swapping out %d\n", p->p_pid); 513 #endif 514 ++p->p_stats->p_ru.ru_nswap; 515 /* 516 * remember the process resident count 517 */ 518 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 519 520 (void) splhigh(); 521 p->p_flag &= ~P_INMEM; 522 p->p_flag |= P_SWAPPING; 523 if (p->p_stat == SRUN) 524 remrunqueue(p); 525 (void) spl0(); 526 527 pmap_swapout_proc(p); 528 529 p->p_flag &= ~P_SWAPPING; 530 p->p_swtime = 0; 531 } 532 #endif /* !NO_SWAPPING */ 533