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 1.16 1995/02/20 17:26:21 davidg Exp $ 63 */ 64 65 #include <sys/param.h> 66 #include <sys/systm.h> 67 #include <sys/proc.h> 68 #include <sys/resourcevar.h> 69 #include <sys/buf.h> 70 #include <sys/user.h> 71 72 #include <sys/kernel.h> 73 #include <sys/dkstat.h> 74 75 #include <vm/vm.h> 76 #include <vm/vm_page.h> 77 #include <vm/vm_pageout.h> 78 #include <vm/vm_kern.h> 79 80 #include <machine/stdarg.h> 81 #include <machine/cpu.h> 82 83 extern char kstack[]; 84 int avefree = 0; /* XXX */ 85 int readbuffers = 0; /* XXX allow kgdb to read kernel buffer pool */ 86 87 /* vm_map_t upages_map; */ 88 89 int 90 kernacc(addr, len, rw) 91 caddr_t addr; 92 int len, rw; 93 { 94 boolean_t rv; 95 vm_offset_t saddr, eaddr; 96 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 97 98 saddr = trunc_page(addr); 99 eaddr = round_page(addr + len); 100 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 101 return (rv == TRUE); 102 } 103 104 int 105 useracc(addr, len, rw) 106 caddr_t addr; 107 int len, rw; 108 { 109 boolean_t rv; 110 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 111 112 /* 113 * XXX - check separately to disallow access to user area and user 114 * page tables - they are in the map. 115 * 116 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once 117 * only used (as an end address) in trap.c. Use it as an end address 118 * here too. This bogusness has spread. I just fixed where it was 119 * used as a max in vm_mmap.c. 120 */ 121 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS 122 || (vm_offset_t) addr + len < (vm_offset_t) addr) { 123 return (FALSE); 124 } 125 rv = vm_map_check_protection(&curproc->p_vmspace->vm_map, 126 trunc_page(addr), round_page(addr + len), prot); 127 return (rv == TRUE); 128 } 129 130 #ifdef KGDB 131 /* 132 * Change protections on kernel pages from addr to addr+len 133 * (presumably so debugger can plant a breakpoint). 134 * All addresses are assumed to reside in the Sysmap, 135 */ 136 chgkprot(addr, len, rw) 137 register caddr_t addr; 138 int len, rw; 139 { 140 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 141 142 vm_map_protect(kernel_map, trunc_page(addr), 143 round_page(addr + len), prot, FALSE); 144 } 145 #endif 146 void 147 vslock(addr, len) 148 caddr_t addr; 149 u_int len; 150 { 151 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr), 152 round_page(addr + len), FALSE); 153 } 154 155 void 156 vsunlock(addr, len, dirtied) 157 caddr_t addr; 158 u_int len; 159 int dirtied; 160 { 161 #ifdef lint 162 dirtied++; 163 #endif /* lint */ 164 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr), 165 round_page(addr + len), TRUE); 166 } 167 168 /* 169 * Implement fork's actions on an address space. 170 * Here we arrange for the address space to be copied or referenced, 171 * allocate a user struct (pcb and kernel stack), then call the 172 * machine-dependent layer to fill those in and make the new process 173 * ready to run. 174 * NOTE: the kernel stack may be at a different location in the child 175 * process, and thus addresses of automatic variables may be invalid 176 * after cpu_fork returns in the child process. We do nothing here 177 * after cpu_fork returns. 178 */ 179 int 180 vm_fork(p1, p2, isvfork) 181 register struct proc *p1, *p2; 182 int isvfork; 183 { 184 register struct user *up; 185 vm_offset_t addr, ptaddr; 186 int i; 187 struct vm_map *vp; 188 189 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 190 VM_WAIT; 191 } 192 193 /* 194 * avoid copying any of the parent's pagetables or other per-process 195 * objects that reside in the map by marking all of them 196 * non-inheritable 197 */ 198 (void) vm_map_inherit(&p1->p_vmspace->vm_map, 199 UPT_MIN_ADDRESS - UPAGES * NBPG, VM_MAX_ADDRESS, VM_INHERIT_NONE); 200 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 201 202 #ifdef SYSVSHM 203 if (p1->p_vmspace->vm_shm) 204 shmfork(p1, p2, isvfork); 205 #endif 206 207 /* 208 * Allocate a wired-down (for now) pcb and kernel stack for the 209 * process 210 */ 211 212 addr = (vm_offset_t) kstack; 213 214 vp = &p2->p_vmspace->vm_map; 215 216 /* get new pagetables and kernel stack */ 217 (void) vm_map_find(vp, NULL, 0, &addr, UPT_MAX_ADDRESS - addr, FALSE); 218 219 /* force in the page table encompassing the UPAGES */ 220 ptaddr = trunc_page((u_int) vtopte(addr)); 221 vm_map_pageable(vp, ptaddr, ptaddr + NBPG, FALSE); 222 223 /* and force in (demand-zero) the UPAGES */ 224 vm_map_pageable(vp, addr, addr + UPAGES * NBPG, FALSE); 225 226 /* get a kernel virtual address for the UPAGES for this proc */ 227 up = (struct user *) kmem_alloc_pageable(u_map, UPAGES * NBPG); 228 if (up == NULL) 229 panic("vm_fork: u_map allocation failed"); 230 231 /* and force-map the upages into the kernel pmap */ 232 for (i = 0; i < UPAGES; i++) 233 pmap_enter(vm_map_pmap(u_map), 234 ((vm_offset_t) up) + NBPG * i, 235 pmap_extract(vp->pmap, addr + NBPG * i), 236 VM_PROT_READ | VM_PROT_WRITE, 1); 237 238 p2->p_addr = up; 239 240 /* 241 * p_stats and p_sigacts currently point at fields in the user struct 242 * but not at &u, instead at p_addr. Copy p_sigacts and parts of 243 * p_stats; zero the rest of p_stats (statistics). 244 */ 245 p2->p_stats = &up->u_stats; 246 p2->p_sigacts = &up->u_sigacts; 247 up->u_sigacts = *p1->p_sigacts; 248 bzero(&up->u_stats.pstat_startzero, 249 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 250 (caddr_t) &up->u_stats.pstat_startzero)); 251 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 252 ((caddr_t) &up->u_stats.pstat_endcopy - 253 (caddr_t) &up->u_stats.pstat_startcopy)); 254 255 256 /* 257 * cpu_fork will copy and update the kernel stack and pcb, and make 258 * the child ready to run. It marks the child so that it can return 259 * differently than the parent. It returns twice, once in the parent 260 * process and once in the child. 261 */ 262 return (cpu_fork(p1, p2)); 263 } 264 265 /* 266 * Set default limits for VM system. 267 * Called for proc 0, and then inherited by all others. 268 */ 269 void 270 vm_init_limits(p) 271 register struct proc *p; 272 { 273 int rss_limit; 274 275 /* 276 * Set up the initial limits on process VM. Set the maximum resident 277 * set size to be half of (reasonably) available memory. Since this 278 * is a soft limit, it comes into effect only when the system is out 279 * of memory - half of main memory helps to favor smaller processes, 280 * and reduces thrashing of the object cache. 281 */ 282 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 283 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 284 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 285 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 286 /* limit the limit to no less than 2MB */ 287 rss_limit = max(cnt.v_free_count / 2, 512); 288 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 289 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 290 } 291 292 #ifdef DEBUG 293 int enableswap = 1; 294 int swapdebug = 0; 295 296 #define SDB_FOLLOW 1 297 #define SDB_SWAPIN 2 298 #define SDB_SWAPOUT 4 299 #endif 300 301 void 302 faultin(p) 303 struct proc *p; 304 { 305 vm_offset_t i; 306 vm_offset_t ptaddr; 307 int s; 308 309 if ((p->p_flag & P_INMEM) == 0) { 310 vm_map_t map; 311 312 ++p->p_lock; 313 314 map = &p->p_vmspace->vm_map; 315 /* force the page table encompassing the kernel stack (upages) */ 316 ptaddr = trunc_page((u_int) vtopte(kstack)); 317 vm_map_pageable(map, ptaddr, ptaddr + NBPG, FALSE); 318 319 /* wire in the UPAGES */ 320 vm_map_pageable(map, (vm_offset_t) kstack, 321 (vm_offset_t) kstack + UPAGES * NBPG, FALSE); 322 323 /* and map them nicely into the kernel pmap */ 324 for (i = 0; i < UPAGES; i++) { 325 vm_offset_t off = i * NBPG; 326 vm_offset_t pa = (vm_offset_t) 327 pmap_extract(&p->p_vmspace->vm_pmap, 328 (vm_offset_t) kstack + off); 329 330 pmap_enter(vm_map_pmap(u_map), 331 ((vm_offset_t) p->p_addr) + off, 332 pa, VM_PROT_READ | VM_PROT_WRITE, 1); 333 } 334 335 s = splhigh(); 336 337 if (p->p_stat == SRUN) 338 setrunqueue(p); 339 340 p->p_flag |= P_INMEM; 341 342 /* undo the effect of setting SLOCK above */ 343 --p->p_lock; 344 splx(s); 345 346 } 347 } 348 349 /* 350 * This swapin algorithm attempts to swap-in processes only if there 351 * is enough space for them. Of course, if a process waits for a long 352 * time, it will be swapped in anyway. 353 */ 354 void 355 scheduler() 356 { 357 register struct proc *p; 358 register int pri; 359 struct proc *pp; 360 int ppri; 361 362 loop: 363 while ((cnt.v_free_count + cnt.v_cache_count) < (cnt.v_free_reserved + UPAGES + 2)) { 364 VM_WAIT; 365 tsleep((caddr_t) &proc0, PVM, "schedm", 0); 366 } 367 368 pp = NULL; 369 ppri = INT_MIN; 370 for (p = (struct proc *) allproc; p != NULL; p = p->p_next) { 371 if (p->p_stat == SRUN && (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { 372 int mempri; 373 374 pri = p->p_swtime + p->p_slptime - p->p_nice * 8; 375 mempri = pri > 0 ? pri : 0; 376 /* 377 * if this process is higher priority and there is 378 * enough space, then select this process instead of 379 * the previous selection. 380 */ 381 if (pri > ppri) { 382 pp = p; 383 ppri = pri; 384 } 385 } 386 } 387 388 /* 389 * Nothing to do, back to sleep 390 */ 391 if ((p = pp) == NULL) { 392 tsleep((caddr_t) &proc0, PVM, "sched", 0); 393 goto loop; 394 } 395 /* 396 * We would like to bring someone in. (only if there is space). 397 */ 398 faultin(p); 399 p->p_swtime = 0; 400 goto loop; 401 } 402 403 #define swappable(p) \ 404 (((p)->p_lock == 0) && \ 405 ((p)->p_flag & (P_TRACED|P_NOSWAP|P_SYSTEM|P_INMEM|P_WEXIT|P_PHYSIO|P_SWAPPING)) == P_INMEM) 406 407 extern int vm_pageout_free_min; 408 409 /* 410 * Swapout is driven by the pageout daemon. Very simple, we find eligible 411 * procs and unwire their u-areas. We try to always "swap" at least one 412 * process in case we need the room for a swapin. 413 * If any procs have been sleeping/stopped for at least maxslp seconds, 414 * they are swapped. Else, we swap the longest-sleeping or stopped process, 415 * if any, otherwise the longest-resident process. 416 */ 417 void 418 swapout_threads() 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 = (struct proc *) allproc; p != NULL; p = p->p_next) { 429 if (!swappable(p)) 430 continue; 431 switch (p->p_stat) { 432 default: 433 continue; 434 435 case SSLEEP: 436 case SSTOP: 437 /* 438 * do not swapout a realtime process 439 */ 440 if (p->p_rtprio.type == RTP_PRIO_REALTIME) 441 continue; 442 443 /* 444 * do not swapout a process waiting on a critical 445 * event of some kind 446 */ 447 if ((p->p_priority & 0x7f) < PSOCK) 448 continue; 449 450 vm_map_reference(&p->p_vmspace->vm_map); 451 /* 452 * do not swapout a process that is waiting for VM 453 * datastructures there is a possible deadlock. 454 */ 455 if (!lock_try_write(&p->p_vmspace->vm_map.lock)) { 456 vm_map_deallocate(&p->p_vmspace->vm_map); 457 continue; 458 } 459 vm_map_unlock(&p->p_vmspace->vm_map); 460 /* 461 * If the process has been asleep for awhile and had 462 * most of its pages taken away already, swap it out. 463 */ 464 if (p->p_slptime > 4) { 465 swapout(p); 466 vm_map_deallocate(&p->p_vmspace->vm_map); 467 didswap++; 468 goto retry; 469 } 470 vm_map_deallocate(&p->p_vmspace->vm_map); 471 } 472 } 473 /* 474 * If we swapped something out, and another process needed memory, 475 * then wakeup the sched process. 476 */ 477 if (didswap) 478 wakeup((caddr_t) &proc0); 479 } 480 481 void 482 swapout(p) 483 register struct proc *p; 484 { 485 vm_map_t map = &p->p_vmspace->vm_map; 486 vm_offset_t ptaddr; 487 488 ++p->p_stats->p_ru.ru_nswap; 489 /* 490 * remember the process resident count 491 */ 492 p->p_vmspace->vm_swrss = 493 p->p_vmspace->vm_pmap.pm_stats.resident_count; 494 495 (void) splhigh(); 496 p->p_flag &= ~P_INMEM; 497 if (p->p_stat == SRUN) 498 remrq(p); 499 (void) spl0(); 500 501 p->p_flag |= P_SWAPPING; 502 /* 503 * let the upages be paged 504 */ 505 pmap_remove(vm_map_pmap(u_map), 506 (vm_offset_t) p->p_addr, ((vm_offset_t) p->p_addr) + UPAGES * NBPG); 507 508 vm_map_pageable(map, (vm_offset_t) kstack, 509 (vm_offset_t) kstack + UPAGES * NBPG, TRUE); 510 511 ptaddr = trunc_page((u_int) vtopte(kstack)); 512 vm_map_pageable(map, ptaddr, ptaddr + NBPG, TRUE); 513 514 p->p_flag &= ~P_SWAPPING; 515 p->p_swtime = 0; 516 } 517 518 /* 519 * The rest of these routines fake thread handling 520 */ 521 522 #ifndef assert_wait 523 void 524 assert_wait(event, ruptible) 525 int event; 526 boolean_t ruptible; 527 { 528 #ifdef lint 529 ruptible++; 530 #endif 531 curproc->p_thread = event; 532 } 533 #endif 534 535 void 536 thread_block(char *msg) 537 { 538 if (curproc->p_thread) 539 tsleep((caddr_t) curproc->p_thread, PVM, msg, 0); 540 } 541 542 543 void 544 thread_sleep_(event, lock, wmesg) 545 int event; 546 simple_lock_t lock; 547 char *wmesg; 548 { 549 550 curproc->p_thread = event; 551 simple_unlock(lock); 552 if (curproc->p_thread) { 553 tsleep((caddr_t) event, PVM, wmesg, 0); 554 } 555 } 556 557 #ifndef thread_wakeup 558 void 559 thread_wakeup(event) 560 int event; 561 { 562 wakeup((caddr_t) event); 563 } 564 #endif 565 566 /* 567 * DEBUG stuff 568 */ 569 570 int indent = 0; 571 572 #include <machine/stdarg.h> /* see subr_prf.c */ 573 574 /*ARGSUSED2*/ 575 void 576 #if __STDC__ 577 iprintf(const char *fmt,...) 578 #else 579 iprintf(fmt /* , va_alist */ ) 580 char *fmt; 581 582 /* va_dcl */ 583 #endif 584 { 585 register int i; 586 va_list ap; 587 588 for (i = indent; i >= 8; i -= 8) 589 printf("\t"); 590 while (--i >= 0) 591 printf(" "); 592 va_start(ap, fmt); 593 printf("%r", fmt, ap); 594 va_end(ap); 595 } 596