1 /* 2 * Copyright (c) 1991 Regents of the University of California. 3 * 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 * %sccs.include.redist.c% 9 * 10 * @(#)vm_glue.c 7.8 (Berkeley) 05/15/91 11 * 12 * 13 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 14 * All rights reserved. 15 * 16 * Permission to use, copy, modify and distribute this software and 17 * its documentation is hereby granted, provided that both the copyright 18 * notice and this permission notice appear in all copies of the 19 * software, derivative works or modified versions, and any portions 20 * thereof, and that both notices appear in supporting documentation. 21 * 22 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 23 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 24 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 25 * 26 * Carnegie Mellon requests users of this software to return to 27 * 28 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 29 * School of Computer Science 30 * Carnegie Mellon University 31 * Pittsburgh PA 15213-3890 32 * 33 * any improvements or extensions that they make and grant Carnegie the 34 * rights to redistribute these changes. 35 */ 36 37 #include "param.h" 38 #include "systm.h" 39 #include "proc.h" 40 #include "resourcevar.h" 41 #include "buf.h" 42 #include "user.h" 43 44 #include "vm.h" 45 #include "vm_page.h" 46 #include "vm_kern.h" 47 48 int avefree = 0; /* XXX */ 49 unsigned maxdmap = MAXDSIZ; /* XXX */ 50 int readbuffers = 0; /* XXX allow kgdb to read kernel buffer pool */ 51 52 kernacc(addr, len, rw) 53 caddr_t addr; 54 int len, rw; 55 { 56 boolean_t rv; 57 vm_offset_t saddr, eaddr; 58 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 59 60 saddr = trunc_page(addr); 61 eaddr = round_page(addr+len-1); 62 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 63 /* 64 * XXX there are still some things (e.g. the buffer cache) that 65 * are managed behind the VM system's back so even though an 66 * address is accessible in the mind of the VM system, there may 67 * not be physical pages where the VM thinks there is. This can 68 * lead to bogus allocation of pages in the kernel address space 69 * or worse, inconsistencies at the pmap level. We only worry 70 * about the buffer cache for now. 71 */ 72 if (!readbuffers && rv && (eaddr > (vm_offset_t)buffers && 73 saddr < (vm_offset_t)buffers + MAXBSIZE * nbuf)) 74 rv = FALSE; 75 return(rv == TRUE); 76 } 77 78 useracc(addr, len, rw) 79 caddr_t addr; 80 int len, rw; 81 { 82 boolean_t rv; 83 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 84 85 rv = vm_map_check_protection(&curproc->p_vmspace->vm_map, 86 trunc_page(addr), round_page(addr+len-1), prot); 87 return(rv == TRUE); 88 } 89 90 #ifdef KGDB 91 /* 92 * Change protections on kernel pages from addr to addr+len 93 * (presumably so debugger can plant a breakpoint). 94 * All addresses are assumed to reside in the Sysmap, 95 */ 96 chgkprot(addr, len, rw) 97 register caddr_t addr; 98 int len, rw; 99 { 100 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 101 102 vm_map_protect(kernel_map, trunc_page(addr), 103 round_page(addr+len-1), prot, FALSE); 104 } 105 #endif 106 107 vslock(addr, len) 108 caddr_t addr; 109 u_int len; 110 { 111 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr), 112 round_page(addr+len-1), FALSE); 113 } 114 115 vsunlock(addr, len, dirtied) 116 caddr_t addr; 117 u_int len; 118 int dirtied; 119 { 120 #ifdef lint 121 dirtied++; 122 #endif lint 123 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr), 124 round_page(addr+len-1), TRUE); 125 } 126 127 /* 128 * Implement fork's actions on an address space. 129 * Here we arrange for the address space to be copied or referenced, 130 * allocate a user struct (pcb and kernel stack), then call the 131 * machine-dependent layer to fill those in and make the new process 132 * ready to run. 133 * NOTE: the kernel stack may be at a different location in the child 134 * process, and thus addresses of automatic variables may be invalid 135 * after cpu_fork returns in the child process. We do nothing here 136 * after cpu_fork returns. 137 */ 138 vm_fork(p1, p2, isvfork) 139 register struct proc *p1, *p2; 140 int isvfork; 141 { 142 register struct user *up; 143 vm_offset_t addr; 144 145 #ifdef i386 146 /* 147 * avoid copying any of the parent's pagetables or other per-process 148 * objects that reside in the map by marking all of them non-inheritable 149 */ 150 (void)vm_map_inherit(&p1->p_vmspace->vm_map, 151 UPT_MIN_ADDRESS-UPAGES*NBPG, VM_MAX_ADDRESS, VM_INHERIT_NONE); 152 #endif 153 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 154 155 #ifdef SYSVSHM 156 if (p1->p_vmspace->vm_shm) 157 shmfork(p1, p2, isvfork); 158 #endif 159 160 /* 161 * Allocate a wired-down (for now) pcb and kernel stack for the process 162 */ 163 addr = kmem_alloc_pageable(kernel_map, ctob(UPAGES)); 164 vm_map_pageable(kernel_map, addr, addr + ctob(UPAGES), FALSE); 165 up = (struct user *)addr; 166 p2->p_addr = up; 167 168 /* 169 * p_stats and p_sigacts currently point at fields 170 * in the user struct but not at &u, instead at p_addr. 171 * Copy p_sigacts and parts of p_stats; zero the rest 172 * of p_stats (statistics). 173 */ 174 p2->p_stats = &up->u_stats; 175 p2->p_sigacts = &up->u_sigacts; 176 up->u_sigacts = *p1->p_sigacts; 177 bzero(&up->u_stats.pstat_startzero, 178 (unsigned) ((caddr_t)&up->u_stats.pstat_endzero - 179 (caddr_t)&up->u_stats.pstat_startzero)); 180 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 181 ((caddr_t)&up->u_stats.pstat_endcopy - 182 (caddr_t)&up->u_stats.pstat_startcopy)); 183 184 #ifdef i386 185 { u_int addr = UPT_MIN_ADDRESS - UPAGES*NBPG; struct vm_map *vp; 186 187 vp = &p2->p_vmspace->vm_map; 188 (void)vm_map_pageable(vp, addr, 0xfe000000 - addr, TRUE); 189 (void)vm_deallocate(vp, addr, 0xfe000000 - addr); 190 (void)vm_allocate(vp, &addr, UPT_MAX_ADDRESS - addr, FALSE); 191 (void)vm_map_inherit(vp, addr, UPT_MAX_ADDRESS, VM_INHERIT_NONE); 192 } 193 #endif 194 /* 195 * cpu_fork will copy and update the kernel stack and pcb, 196 * and make the child ready to run. It marks the child 197 * so that it can return differently than the parent. 198 * It returns twice, once in the parent process and 199 * once in the child. 200 */ 201 return (cpu_fork(p1, p2)); 202 } 203 204 /* 205 * Set default limits for VM system. 206 * Called for proc 0, and then inherited by all others. 207 */ 208 vm_init_limits(p) 209 register struct proc *p; 210 { 211 212 /* 213 * Set up the initial limits on process VM. 214 * Set the maximum resident set size to be all 215 * of (reasonably) available memory. This causes 216 * any single, large process to start random page 217 * replacement once it fills memory. 218 */ 219 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 220 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 221 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 222 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 223 p->p_rlimit[RLIMIT_RSS].rlim_cur = p->p_rlimit[RLIMIT_RSS].rlim_max = 224 ptoa(vm_page_free_count); 225 } 226 227 #include "../vm/vm_pageout.h" 228 229 #ifdef DEBUG 230 int enableswap = 1; 231 int swapdebug = 0; 232 #define SDB_FOLLOW 1 233 #define SDB_SWAPIN 2 234 #define SDB_SWAPOUT 4 235 #endif 236 237 /* 238 * Brutally simple: 239 * 1. Attempt to swapin every swaped-out, runnable process in 240 * order of priority. 241 * 2. If not enough memory, wake the pageout daemon and let it 242 * clear some space. 243 */ 244 sched() 245 { 246 register struct proc *p; 247 register int pri; 248 struct proc *pp; 249 int ppri; 250 vm_offset_t addr; 251 vm_size_t size; 252 253 loop: 254 #ifdef DEBUG 255 if (!enableswap) { 256 pp = NULL; 257 goto noswap; 258 } 259 #endif 260 pp = NULL; 261 ppri = INT_MIN; 262 for (p = allproc; p != NULL; p = p->p_nxt) 263 if (p->p_stat == SRUN && (p->p_flag & SLOAD) == 0) { 264 pri = p->p_time + p->p_slptime - p->p_nice * 8; 265 if (pri > ppri) { 266 pp = p; 267 ppri = pri; 268 } 269 } 270 #ifdef DEBUG 271 if (swapdebug & SDB_FOLLOW) 272 printf("sched: running, procp %x pri %d\n", pp, ppri); 273 noswap: 274 #endif 275 /* 276 * Nothing to do, back to sleep 277 */ 278 if ((p = pp) == NULL) { 279 sleep((caddr_t)&proc0, PVM); 280 goto loop; 281 } 282 283 /* 284 * We would like to bring someone in. 285 * This part is really bogus cuz we could deadlock on memory 286 * despite our feeble check. 287 */ 288 size = round_page(ctob(UPAGES)); 289 addr = (vm_offset_t) p->p_addr; 290 if (vm_page_free_count > atop(size)) { 291 #ifdef DEBUG 292 if (swapdebug & SDB_SWAPIN) 293 printf("swapin: pid %d(%s)@%x, pri %d free %d\n", 294 p->p_pid, p->p_comm, p->p_addr, 295 ppri, vm_page_free_count); 296 #endif 297 vm_map_pageable(kernel_map, addr, addr+size, FALSE); 298 (void) splclock(); 299 if (p->p_stat == SRUN) 300 setrq(p); 301 p->p_flag |= SLOAD; 302 (void) spl0(); 303 p->p_time = 0; 304 goto loop; 305 } 306 /* 307 * Not enough memory, jab the pageout daemon and wait til the 308 * coast is clear. 309 */ 310 #ifdef DEBUG 311 if (swapdebug & SDB_FOLLOW) 312 printf("sched: no room for pid %d(%s), free %d\n", 313 p->p_pid, p->p_comm, vm_page_free_count); 314 #endif 315 (void) splhigh(); 316 VM_WAIT; 317 (void) spl0(); 318 #ifdef DEBUG 319 if (swapdebug & SDB_FOLLOW) 320 printf("sched: room again, free %d\n", vm_page_free_count); 321 #endif 322 goto loop; 323 } 324 325 #define swappable(p) \ 326 (((p)->p_flag & (SSYS|SLOAD|SKEEP|SWEXIT|SPHYSIO)) == SLOAD) 327 328 /* 329 * Swapout is driven by the pageout daemon. Very simple, we find eligible 330 * procs and unwire their u-areas. We try to always "swap" at least one 331 * process in case we need the room for a swapin. 332 * If any procs have been sleeping/stopped for at least maxslp seconds, 333 * they are swapped. Else, we swap the longest-sleeping or stopped process, 334 * if any, otherwise the longest-resident process. 335 */ 336 swapout_threads() 337 { 338 register struct proc *p; 339 struct proc *outp, *outp2; 340 int outpri, outpri2; 341 int didswap = 0; 342 extern int maxslp; 343 344 #ifdef DEBUG 345 if (!enableswap) 346 return; 347 #endif 348 outp = outp2 = NULL; 349 outpri = outpri2 = 0; 350 for (p = allproc; p != NULL; p = p->p_nxt) { 351 if (!swappable(p)) 352 continue; 353 switch (p->p_stat) { 354 case SRUN: 355 if (p->p_time > outpri2) { 356 outp2 = p; 357 outpri2 = p->p_time; 358 } 359 continue; 360 361 case SSLEEP: 362 case SSTOP: 363 if (p->p_slptime > maxslp) { 364 swapout(p); 365 didswap++; 366 } else if (p->p_slptime > outpri) { 367 outp = p; 368 outpri = p->p_slptime; 369 } 370 continue; 371 } 372 } 373 /* 374 * If we didn't get rid of any real duds, toss out the next most 375 * likely sleeping/stopped or running candidate. We only do this 376 * if we are real low on memory since we don't gain much by doing 377 * it (UPAGES pages). 378 */ 379 if (didswap == 0 && 380 vm_page_free_count <= atop(round_page(ctob(UPAGES)))) { 381 if ((p = outp) == 0) 382 p = outp2; 383 #ifdef DEBUG 384 if (swapdebug & SDB_SWAPOUT) 385 printf("swapout_threads: no duds, try procp %x\n", p); 386 #endif 387 if (p) 388 swapout(p); 389 } 390 } 391 392 swapout(p) 393 register struct proc *p; 394 { 395 vm_offset_t addr; 396 vm_size_t size; 397 398 #ifdef DEBUG 399 if (swapdebug & SDB_SWAPOUT) 400 printf("swapout: pid %d(%s)@%x, stat %x pri %d free %d\n", 401 p->p_pid, p->p_comm, p->p_addr, p->p_stat, 402 p->p_slptime, vm_page_free_count); 403 #endif 404 size = round_page(ctob(UPAGES)); 405 addr = (vm_offset_t) p->p_addr; 406 #ifdef hp300 407 /* 408 * Ugh! u-area is double mapped to a fixed address behind the 409 * back of the VM system and accesses are usually through that 410 * address rather than the per-process address. Hence reference 411 * and modify information are recorded at the fixed address and 412 * lost at context switch time. We assume the u-struct and 413 * kernel stack are always accessed/modified and force it to be so. 414 */ 415 { 416 register int i; 417 volatile long tmp; 418 419 for (i = 0; i < UPAGES; i++) { 420 tmp = *(long *)addr; *(long *)addr = tmp; 421 addr += NBPG; 422 } 423 addr = (vm_offset_t) p->p_addr; 424 } 425 #endif 426 vm_map_pageable(kernel_map, addr, addr+size, TRUE); 427 pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map)); 428 (void) splhigh(); 429 p->p_flag &= ~SLOAD; 430 if (p->p_stat == SRUN) 431 remrq(p); 432 (void) spl0(); 433 p->p_time = 0; 434 } 435 436 /* 437 * The rest of these routines fake thread handling 438 */ 439 440 void 441 assert_wait(event, ruptible) 442 int event; 443 boolean_t ruptible; 444 { 445 #ifdef lint 446 ruptible++; 447 #endif 448 curproc->p_thread = event; 449 } 450 451 void 452 thread_block() 453 { 454 int s = splhigh(); 455 456 if (curproc->p_thread) 457 sleep((caddr_t)curproc->p_thread, PVM); 458 splx(s); 459 } 460 461 thread_sleep(event, lock, ruptible) 462 int event; 463 simple_lock_t lock; 464 boolean_t ruptible; 465 { 466 #ifdef lint 467 ruptible++; 468 #endif 469 int s = splhigh(); 470 471 curproc->p_thread = event; 472 simple_unlock(lock); 473 if (curproc->p_thread) 474 sleep((caddr_t)event, PVM); 475 splx(s); 476 } 477 478 thread_wakeup(event) 479 int event; 480 { 481 int s = splhigh(); 482 483 wakeup((caddr_t)event); 484 splx(s); 485 } 486 487 /* 488 * DEBUG stuff 489 */ 490 491 int indent = 0; 492 493 /*ARGSUSED2*/ 494 iprintf(a, b, c, d, e, f, g, h) 495 char *a; 496 { 497 register int i; 498 499 i = indent; 500 while (i >= 8) { 501 printf("\t"); 502 i -= 8; 503 } 504 for (; i > 0; --i) 505 printf(" "); 506 printf(a, b, c, d, e, f, g, h); 507 } 508