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 1.54 1996/10/15 03:16:44 dyson 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/shm.h> 71 #include <sys/vmmeter.h> 72 73 #include <sys/kernel.h> 74 #include <sys/dkstat.h> 75 76 #include <vm/vm.h> 77 #include <vm/vm_param.h> 78 #include <vm/vm_inherit.h> 79 #include <vm/vm_prot.h> 80 #include <vm/lock.h> 81 #include <vm/pmap.h> 82 #include <vm/vm_map.h> 83 #include <vm/vm_page.h> 84 #include <vm/vm_pageout.h> 85 #include <vm/vm_kern.h> 86 #include <vm/vm_extern.h> 87 #include <vm/vm_object.h> 88 #include <vm/vm_pager.h> 89 90 #include <sys/user.h> 91 92 /* 93 * System initialization 94 * 95 * Note: proc0 from proc.h 96 */ 97 98 static void vm_init_limits __P((void *)); 99 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) 100 101 /* 102 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 103 * 104 * Note: run scheduling should be divorced from the vm system. 105 */ 106 static void scheduler __P((void *)); 107 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 108 109 110 static void swapout __P((struct proc *)); 111 112 extern char kstack[]; 113 114 /* vm_map_t upages_map; */ 115 116 int 117 kernacc(addr, len, rw) 118 caddr_t addr; 119 int len, rw; 120 { 121 boolean_t rv; 122 vm_offset_t saddr, eaddr; 123 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 124 125 saddr = trunc_page(addr); 126 eaddr = round_page(addr + len); 127 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 128 return (rv == TRUE); 129 } 130 131 int 132 useracc(addr, len, rw) 133 caddr_t addr; 134 int len, rw; 135 { 136 boolean_t rv; 137 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 138 139 /* 140 * XXX - check separately to disallow access to user area and user 141 * page tables - they are in the map. 142 * 143 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once 144 * only used (as an end address) in trap.c. Use it as an end address 145 * here too. This bogusness has spread. I just fixed where it was 146 * used as a max in vm_mmap.c. 147 */ 148 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS 149 || (vm_offset_t) addr + len < (vm_offset_t) addr) { 150 return (FALSE); 151 } 152 rv = vm_map_check_protection(&curproc->p_vmspace->vm_map, 153 trunc_page(addr), round_page(addr + len), prot); 154 return (rv == TRUE); 155 } 156 157 void 158 vslock(addr, len) 159 caddr_t addr; 160 u_int len; 161 { 162 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr), 163 round_page(addr + len), FALSE); 164 } 165 166 void 167 vsunlock(addr, len, dirtied) 168 caddr_t addr; 169 u_int len; 170 int dirtied; 171 { 172 #ifdef lint 173 dirtied++; 174 #endif /* lint */ 175 vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr), 176 round_page(addr + len), TRUE); 177 } 178 179 /* 180 * Implement fork's actions on an address space. 181 * Here we arrange for the address space to be copied or referenced, 182 * allocate a user struct (pcb and kernel stack), then call the 183 * machine-dependent layer to fill those in and make the new process 184 * ready to run. 185 * NOTE: the kernel stack may be at a different location in the child 186 * process, and thus addresses of automatic variables may be invalid 187 * after cpu_fork returns in the child process. We do nothing here 188 * after cpu_fork returns. 189 */ 190 int 191 vm_fork(p1, p2) 192 register struct proc *p1, *p2; 193 { 194 register struct user *up; 195 int i; 196 pmap_t pvp; 197 vm_object_t upobj; 198 199 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 200 VM_WAIT; 201 } 202 203 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 204 205 if (p1->p_vmspace->vm_shm) 206 shmfork(p1, p2); 207 208 pmap_new_proc(p2); 209 210 up = p2->p_addr; 211 212 /* 213 * p_stats and p_sigacts currently point at fields in the user struct 214 * but not at &u, instead at p_addr. Copy p_sigacts and parts of 215 * p_stats; zero the rest of p_stats (statistics). 216 */ 217 p2->p_stats = &up->u_stats; 218 p2->p_sigacts = &up->u_sigacts; 219 up->u_sigacts = *p1->p_sigacts; 220 bzero(&up->u_stats.pstat_startzero, 221 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 222 (caddr_t) &up->u_stats.pstat_startzero)); 223 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 224 ((caddr_t) &up->u_stats.pstat_endcopy - 225 (caddr_t) &up->u_stats.pstat_startcopy)); 226 227 228 /* 229 * cpu_fork will copy and update the kernel stack and pcb, and make 230 * the child ready to run. It marks the child so that it can return 231 * differently than the parent. It returns twice, once in the parent 232 * process and once in the child. 233 */ 234 return (cpu_fork(p1, p2)); 235 } 236 237 /* 238 * Set default limits for VM system. 239 * Called for proc 0, and then inherited by all others. 240 * 241 * XXX should probably act directly on proc0. 242 */ 243 static void 244 vm_init_limits(udata) 245 void *udata; 246 { 247 register struct proc *p = udata; 248 int rss_limit; 249 250 /* 251 * Set up the initial limits on process VM. Set the maximum resident 252 * set size to be half of (reasonably) available memory. Since this 253 * is a soft limit, it comes into effect only when the system is out 254 * of memory - half of main memory helps to favor smaller processes, 255 * and reduces thrashing of the object cache. 256 */ 257 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 258 p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ; 259 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 260 p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ; 261 /* limit the limit to no less than 2MB */ 262 rss_limit = max(cnt.v_free_count, 512); 263 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 264 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 265 } 266 267 void 268 faultin(p) 269 struct proc *p; 270 { 271 vm_offset_t i; 272 int s; 273 274 if ((p->p_flag & P_INMEM) == 0) { 275 276 ++p->p_lock; 277 278 pmap_swapin_proc(p); 279 280 s = splhigh(); 281 282 if (p->p_stat == SRUN) 283 setrunqueue(p); 284 285 p->p_flag |= P_INMEM; 286 287 /* undo the effect of setting SLOCK above */ 288 --p->p_lock; 289 splx(s); 290 291 } 292 } 293 294 /* 295 * This swapin algorithm attempts to swap-in processes only if there 296 * is enough space for them. Of course, if a process waits for a long 297 * time, it will be swapped in anyway. 298 */ 299 /* ARGSUSED*/ 300 static void 301 scheduler(dummy) 302 void *dummy; 303 { 304 register struct proc *p; 305 register int pri; 306 struct proc *pp; 307 int ppri; 308 309 spl0(); 310 loop: 311 while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { 312 VM_WAIT; 313 } 314 315 pp = NULL; 316 ppri = INT_MIN; 317 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 318 if (p->p_stat == SRUN && 319 (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { 320 int mempri; 321 322 pri = p->p_swtime + p->p_slptime; 323 if ((p->p_flag & P_SWAPINREQ) == 0) { 324 pri -= p->p_nice * 8; 325 } 326 mempri = pri > 0 ? pri : 0; 327 /* 328 * if this process is higher priority and there is 329 * enough space, then select this process instead of 330 * the previous selection. 331 */ 332 if (pri > ppri) { 333 pp = p; 334 ppri = pri; 335 } 336 } 337 } 338 339 /* 340 * Nothing to do, back to sleep. 341 */ 342 if ((p = pp) == NULL) { 343 tsleep(&proc0, PVM, "sched", 0); 344 goto loop; 345 } 346 p->p_flag &= ~P_SWAPINREQ; 347 348 /* 349 * We would like to bring someone in. (only if there is space). 350 */ 351 faultin(p); 352 p->p_swtime = 0; 353 goto loop; 354 } 355 356 #ifndef NO_SWAPPING 357 358 #define swappable(p) \ 359 (((p)->p_lock == 0) && \ 360 ((p)->p_flag & (P_TRACED|P_NOSWAP|P_SYSTEM|P_INMEM|P_WEXIT|P_PHYSIO|P_SWAPPING)) == P_INMEM) 361 362 /* 363 * Swapout is driven by the pageout daemon. Very simple, we find eligible 364 * procs and unwire their u-areas. We try to always "swap" at least one 365 * process in case we need the room for a swapin. 366 * If any procs have been sleeping/stopped for at least maxslp seconds, 367 * they are swapped. Else, we swap the longest-sleeping or stopped process, 368 * if any, otherwise the longest-resident process. 369 */ 370 void 371 swapout_procs() 372 { 373 register struct proc *p; 374 struct proc *outp, *outp2; 375 int outpri, outpri2; 376 int didswap = 0; 377 378 outp = outp2 = NULL; 379 outpri = outpri2 = INT_MIN; 380 retry: 381 for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { 382 struct vmspace *vm; 383 if (!swappable(p)) 384 continue; 385 386 vm = p->p_vmspace; 387 388 switch (p->p_stat) { 389 default: 390 continue; 391 392 case SSLEEP: 393 case SSTOP: 394 /* 395 * do not swapout a realtime process 396 */ 397 if (p->p_rtprio.type == RTP_PRIO_REALTIME) 398 continue; 399 400 /* 401 * do not swapout a process waiting on a critical 402 * event of some kind 403 */ 404 if (((p->p_priority & 0x7f) < PSOCK) || 405 (p->p_slptime <= 10)) 406 continue; 407 408 ++vm->vm_refcnt; 409 vm_map_reference(&vm->vm_map); 410 /* 411 * do not swapout a process that is waiting for VM 412 * datastructures there is a possible deadlock. 413 */ 414 if (!lock_try_write(&vm->vm_map.lock)) { 415 vm_map_deallocate(&vm->vm_map); 416 vmspace_free(vm); 417 continue; 418 } 419 vm_map_unlock(&vm->vm_map); 420 /* 421 * If the process has been asleep for awhile and had 422 * most of its pages taken away already, swap it out. 423 */ 424 swapout(p); 425 vm_map_deallocate(&vm->vm_map); 426 vmspace_free(vm); 427 didswap++; 428 goto retry; 429 } 430 } 431 /* 432 * If we swapped something out, and another process needed memory, 433 * then wakeup the sched process. 434 */ 435 if (didswap) 436 wakeup(&proc0); 437 } 438 439 static void 440 swapout(p) 441 register struct proc *p; 442 { 443 pmap_t pmap = &p->p_vmspace->vm_pmap; 444 int i; 445 446 #if defined(SWAP_DEBUG) 447 printf("swapping out %d\n", p->p_pid); 448 #endif 449 ++p->p_stats->p_ru.ru_nswap; 450 /* 451 * remember the process resident count 452 */ 453 p->p_vmspace->vm_swrss = 454 p->p_vmspace->vm_pmap.pm_stats.resident_count; 455 456 (void) splhigh(); 457 p->p_flag &= ~P_INMEM; 458 p->p_flag |= P_SWAPPING; 459 if (p->p_stat == SRUN) 460 remrq(p); 461 (void) spl0(); 462 463 pmap_swapout_proc(p); 464 465 p->p_flag &= ~P_SWAPPING; 466 p->p_swtime = 0; 467 } 468 #endif /* !NO_SWAPPING */ 469