1 /* $NetBSD: uvm_glue.c,v 1.137 2009/04/16 00:17:19 rmind Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Charles D. Cranor and Washington University. 5 * Copyright (c) 1991, 1993, The Regents of the University of California. 6 * 7 * All rights reserved. 8 * 9 * This code is derived from software contributed to Berkeley by 10 * The Mach Operating System project at Carnegie-Mellon University. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by Charles D. Cranor, 23 * Washington University, the University of California, Berkeley and 24 * its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 42 * from: Id: uvm_glue.c,v 1.1.2.8 1998/02/07 01:16:54 chs Exp 43 * 44 * 45 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 46 * All rights reserved. 47 * 48 * Permission to use, copy, modify and distribute this software and 49 * its documentation is hereby granted, provided that both the copyright 50 * notice and this permission notice appear in all copies of the 51 * software, derivative works or modified versions, and any portions 52 * thereof, and that both notices appear in supporting documentation. 53 * 54 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 55 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 56 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 57 * 58 * Carnegie Mellon requests users of this software to return to 59 * 60 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 61 * School of Computer Science 62 * Carnegie Mellon University 63 * Pittsburgh PA 15213-3890 64 * 65 * any improvements or extensions that they make and grant Carnegie the 66 * rights to redistribute these changes. 67 */ 68 69 #include <sys/cdefs.h> 70 __KERNEL_RCSID(0, "$NetBSD: uvm_glue.c,v 1.137 2009/04/16 00:17:19 rmind Exp $"); 71 72 #include "opt_kgdb.h" 73 #include "opt_kstack.h" 74 #include "opt_uvmhist.h" 75 76 /* 77 * uvm_glue.c: glue functions 78 */ 79 80 #include <sys/param.h> 81 #include <sys/systm.h> 82 #include <sys/proc.h> 83 #include <sys/resourcevar.h> 84 #include <sys/buf.h> 85 #include <sys/user.h> 86 #include <sys/syncobj.h> 87 #include <sys/cpu.h> 88 #include <sys/atomic.h> 89 90 #include <uvm/uvm.h> 91 92 /* 93 * local prototypes 94 */ 95 96 static void uvm_swapout(struct lwp *); 97 static int uarea_swapin(vaddr_t); 98 99 /* 100 * XXXCDC: do these really belong here? 101 */ 102 103 /* 104 * uvm_kernacc: can the kernel access a region of memory 105 * 106 * - used only by /dev/kmem driver (mem.c) 107 */ 108 109 bool 110 uvm_kernacc(void *addr, size_t len, int rw) 111 { 112 bool rv; 113 vaddr_t saddr, eaddr; 114 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 115 116 saddr = trunc_page((vaddr_t)addr); 117 eaddr = round_page((vaddr_t)addr + len); 118 vm_map_lock_read(kernel_map); 119 rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot); 120 vm_map_unlock_read(kernel_map); 121 122 return(rv); 123 } 124 125 #ifdef KGDB 126 /* 127 * Change protections on kernel pages from addr to addr+len 128 * (presumably so debugger can plant a breakpoint). 129 * 130 * We force the protection change at the pmap level. If we were 131 * to use vm_map_protect a change to allow writing would be lazily- 132 * applied meaning we would still take a protection fault, something 133 * we really don't want to do. It would also fragment the kernel 134 * map unnecessarily. We cannot use pmap_protect since it also won't 135 * enforce a write-enable request. Using pmap_enter is the only way 136 * we can ensure the change takes place properly. 137 */ 138 void 139 uvm_chgkprot(void *addr, size_t len, int rw) 140 { 141 vm_prot_t prot; 142 paddr_t pa; 143 vaddr_t sva, eva; 144 145 prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE; 146 eva = round_page((vaddr_t)addr + len); 147 for (sva = trunc_page((vaddr_t)addr); sva < eva; sva += PAGE_SIZE) { 148 /* 149 * Extract physical address for the page. 150 */ 151 if (pmap_extract(pmap_kernel(), sva, &pa) == false) 152 panic("%s: invalid page", __func__); 153 pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED); 154 } 155 pmap_update(pmap_kernel()); 156 } 157 #endif 158 159 /* 160 * uvm_vslock: wire user memory for I/O 161 * 162 * - called from physio and sys___sysctl 163 * - XXXCDC: consider nuking this (or making it a macro?) 164 */ 165 166 int 167 uvm_vslock(struct vmspace *vs, void *addr, size_t len, vm_prot_t access_type) 168 { 169 struct vm_map *map; 170 vaddr_t start, end; 171 int error; 172 173 map = &vs->vm_map; 174 start = trunc_page((vaddr_t)addr); 175 end = round_page((vaddr_t)addr + len); 176 error = uvm_fault_wire(map, start, end, access_type, 0); 177 return error; 178 } 179 180 /* 181 * uvm_vsunlock: unwire user memory wired by uvm_vslock() 182 * 183 * - called from physio and sys___sysctl 184 * - XXXCDC: consider nuking this (or making it a macro?) 185 */ 186 187 void 188 uvm_vsunlock(struct vmspace *vs, void *addr, size_t len) 189 { 190 uvm_fault_unwire(&vs->vm_map, trunc_page((vaddr_t)addr), 191 round_page((vaddr_t)addr + len)); 192 } 193 194 /* 195 * uvm_proc_fork: fork a virtual address space 196 * 197 * - the address space is copied as per parent map's inherit values 198 */ 199 void 200 uvm_proc_fork(struct proc *p1, struct proc *p2, bool shared) 201 { 202 203 if (shared == true) { 204 p2->p_vmspace = NULL; 205 uvmspace_share(p1, p2); 206 } else { 207 p2->p_vmspace = uvmspace_fork(p1->p_vmspace); 208 } 209 210 cpu_proc_fork(p1, p2); 211 } 212 213 214 /* 215 * uvm_lwp_fork: fork a thread 216 * 217 * - a new "user" structure is allocated for the child process 218 * [filled in by MD layer...] 219 * - if specified, the child gets a new user stack described by 220 * stack and stacksize 221 * - NOTE: the kernel stack may be at a different location in the child 222 * process, and thus addresses of automatic variables may be invalid 223 * after cpu_lwp_fork returns in the child process. We do nothing here 224 * after cpu_lwp_fork returns. 225 * - XXXCDC: we need a way for this to return a failure value rather 226 * than just hang 227 */ 228 void 229 uvm_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize, 230 void (*func)(void *), void *arg) 231 { 232 int error; 233 234 /* 235 * Wire down the U-area for the process, which contains the PCB 236 * and the kernel stack. Wired state is stored in l->l_flag's 237 * L_INMEM bit rather than in the vm_map_entry's wired count 238 * to prevent kernel_map fragmentation. If we reused a cached U-area, 239 * L_INMEM will already be set and we don't need to do anything. 240 * 241 * Note the kernel stack gets read/write accesses right off the bat. 242 */ 243 244 if ((l2->l_flag & LW_INMEM) == 0) { 245 vaddr_t uarea = USER_TO_UAREA(l2->l_addr); 246 247 if ((error = uarea_swapin(uarea)) != 0) 248 panic("%s: uvm_fault_wire failed: %d", __func__, error); 249 #ifdef PMAP_UAREA 250 /* Tell the pmap this is a u-area mapping */ 251 PMAP_UAREA(uarea); 252 #endif 253 l2->l_flag |= LW_INMEM; 254 } 255 256 /* Fill stack with magic number. */ 257 kstack_setup_magic(l2); 258 259 /* 260 * cpu_lwp_fork() copy and update the pcb, and make the child ready 261 * to run. If this is a normal user fork, the child will exit 262 * directly to user mode via child_return() on its first time 263 * slice and will not return here. If this is a kernel thread, 264 * the specified entry point will be executed. 265 */ 266 cpu_lwp_fork(l1, l2, stack, stacksize, func, arg); 267 } 268 269 static int 270 uarea_swapin(vaddr_t addr) 271 { 272 273 return uvm_fault_wire(kernel_map, addr, addr + USPACE, 274 VM_PROT_READ | VM_PROT_WRITE, 0); 275 } 276 277 static void 278 uarea_swapout(vaddr_t addr) 279 { 280 281 uvm_fault_unwire(kernel_map, addr, addr + USPACE); 282 } 283 284 #ifndef USPACE_ALIGN 285 #define USPACE_ALIGN 0 286 #endif 287 288 static pool_cache_t uvm_uarea_cache; 289 290 static int 291 uarea_ctor(void *arg, void *obj, int flags) 292 { 293 294 KASSERT((flags & PR_WAITOK) != 0); 295 return uarea_swapin((vaddr_t)obj); 296 } 297 298 static void * 299 uarea_poolpage_alloc(struct pool *pp, int flags) 300 { 301 302 return (void *)uvm_km_alloc(kernel_map, pp->pr_alloc->pa_pagesz, 303 USPACE_ALIGN, UVM_KMF_PAGEABLE | 304 ((flags & PR_WAITOK) != 0 ? UVM_KMF_WAITVA : 305 (UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK))); 306 } 307 308 static void 309 uarea_poolpage_free(struct pool *pp, void *addr) 310 { 311 312 uvm_km_free(kernel_map, (vaddr_t)addr, pp->pr_alloc->pa_pagesz, 313 UVM_KMF_PAGEABLE); 314 } 315 316 static struct pool_allocator uvm_uarea_allocator = { 317 .pa_alloc = uarea_poolpage_alloc, 318 .pa_free = uarea_poolpage_free, 319 .pa_pagesz = USPACE, 320 }; 321 322 void 323 uvm_uarea_init(void) 324 { 325 int flags = PR_NOTOUCH; 326 327 /* 328 * specify PR_NOALIGN unless the alignment provided by 329 * the backend (USPACE_ALIGN) is sufficient to provide 330 * pool page size (UPSACE) alignment. 331 */ 332 333 if ((USPACE_ALIGN == 0 && USPACE != PAGE_SIZE) || 334 (USPACE_ALIGN % USPACE) != 0) { 335 flags |= PR_NOALIGN; 336 } 337 338 uvm_uarea_cache = pool_cache_init(USPACE, USPACE_ALIGN, 0, flags, 339 "uarea", &uvm_uarea_allocator, IPL_NONE, uarea_ctor, NULL, NULL); 340 } 341 342 /* 343 * uvm_uarea_alloc: allocate a u-area 344 */ 345 346 bool 347 uvm_uarea_alloc(vaddr_t *uaddrp) 348 { 349 350 *uaddrp = (vaddr_t)pool_cache_get(uvm_uarea_cache, PR_WAITOK); 351 return true; 352 } 353 354 /* 355 * uvm_uarea_free: free a u-area 356 */ 357 358 void 359 uvm_uarea_free(vaddr_t uaddr, struct cpu_info *ci) 360 { 361 362 pool_cache_put(uvm_uarea_cache, (void *)uaddr); 363 } 364 365 /* 366 * uvm_proc_exit: exit a virtual address space 367 * 368 * - borrow proc0's address space because freeing the vmspace 369 * of the dead process may block. 370 */ 371 372 void 373 uvm_proc_exit(struct proc *p) 374 { 375 struct lwp *l = curlwp; /* XXX */ 376 struct vmspace *ovm; 377 378 KASSERT(p == l->l_proc); 379 ovm = p->p_vmspace; 380 381 /* 382 * borrow proc0's address space. 383 */ 384 KPREEMPT_DISABLE(l); 385 pmap_deactivate(l); 386 p->p_vmspace = proc0.p_vmspace; 387 pmap_activate(l); 388 KPREEMPT_ENABLE(l); 389 390 uvmspace_free(ovm); 391 } 392 393 void 394 uvm_lwp_exit(struct lwp *l) 395 { 396 vaddr_t va = USER_TO_UAREA(l->l_addr); 397 398 l->l_flag &= ~LW_INMEM; 399 uvm_uarea_free(va, l->l_cpu); 400 l->l_addr = NULL; 401 } 402 403 /* 404 * uvm_init_limit: init per-process VM limits 405 * 406 * - called for process 0 and then inherited by all others. 407 */ 408 409 void 410 uvm_init_limits(struct proc *p) 411 { 412 413 /* 414 * Set up the initial limits on process VM. Set the maximum 415 * resident set size to be all of (reasonably) available memory. 416 * This causes any single, large process to start random page 417 * replacement once it fills memory. 418 */ 419 420 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 421 p->p_rlimit[RLIMIT_STACK].rlim_max = maxsmap; 422 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 423 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdmap; 424 p->p_rlimit[RLIMIT_AS].rlim_cur = RLIM_INFINITY; 425 p->p_rlimit[RLIMIT_AS].rlim_max = RLIM_INFINITY; 426 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(uvmexp.free); 427 } 428 429 #ifdef DEBUG 430 int enableswap = 1; 431 int swapdebug = 0; 432 #define SDB_FOLLOW 1 433 #define SDB_SWAPIN 2 434 #define SDB_SWAPOUT 4 435 #endif 436 437 /* 438 * uvm_swapin: swap in an lwp's u-area. 439 * 440 * - must be called with the LWP's swap lock held. 441 * - naturally, must not be called with l == curlwp 442 */ 443 444 void 445 uvm_swapin(struct lwp *l) 446 { 447 int error; 448 449 KASSERT(mutex_owned(&l->l_swaplock)); 450 KASSERT(l != curlwp); 451 452 error = uarea_swapin(USER_TO_UAREA(l->l_addr)); 453 if (error) { 454 panic("%s: rewiring stack failed: %d", __func__, error); 455 } 456 457 /* 458 * Some architectures need to be notified when the user area has 459 * moved to new physical page(s) (e.g. see mips/mips/vm_machdep.c). 460 */ 461 cpu_swapin(l); 462 lwp_lock(l); 463 if (l->l_stat == LSRUN) 464 sched_enqueue(l, false); 465 l->l_flag |= LW_INMEM; 466 l->l_swtime = 0; 467 lwp_unlock(l); 468 ++uvmexp.swapins; 469 } 470 471 /* 472 * uvm_kick_scheduler: kick the scheduler into action if not running. 473 * 474 * - called when swapped out processes have been awoken. 475 */ 476 477 void 478 uvm_kick_scheduler(void) 479 { 480 481 if (uvm.swap_running == false) 482 return; 483 484 mutex_enter(&uvm_scheduler_mutex); 485 uvm.scheduler_kicked = true; 486 cv_signal(&uvm.scheduler_cv); 487 mutex_exit(&uvm_scheduler_mutex); 488 } 489 490 /* 491 * uvm_scheduler: process zero main loop 492 * 493 * - attempt to swapin every swaped-out, runnable process in order of 494 * priority. 495 * - if not enough memory, wake the pagedaemon and let it clear space. 496 */ 497 498 void 499 uvm_scheduler(void) 500 { 501 struct lwp *l, *ll; 502 int pri; 503 int ppri; 504 505 l = curlwp; 506 lwp_lock(l); 507 l->l_priority = PRI_VM; 508 l->l_class = SCHED_FIFO; 509 lwp_unlock(l); 510 511 for (;;) { 512 #ifdef DEBUG 513 mutex_enter(&uvm_scheduler_mutex); 514 while (!enableswap) 515 cv_wait(&uvm.scheduler_cv, &uvm_scheduler_mutex); 516 mutex_exit(&uvm_scheduler_mutex); 517 #endif 518 ll = NULL; /* process to choose */ 519 ppri = INT_MIN; /* its priority */ 520 521 mutex_enter(proc_lock); 522 LIST_FOREACH(l, &alllwp, l_list) { 523 /* is it a runnable swapped out process? */ 524 if (l->l_stat == LSRUN && !(l->l_flag & LW_INMEM)) { 525 pri = l->l_swtime + l->l_slptime - 526 (l->l_proc->p_nice - NZERO) * 8; 527 if (pri > ppri) { /* higher priority? */ 528 ll = l; 529 ppri = pri; 530 } 531 } 532 } 533 #ifdef DEBUG 534 if (swapdebug & SDB_FOLLOW) 535 printf("%s: running, procp %p pri %d\n", __func__, ll, 536 ppri); 537 #endif 538 /* 539 * Nothing to do, back to sleep 540 */ 541 if ((l = ll) == NULL) { 542 mutex_exit(proc_lock); 543 mutex_enter(&uvm_scheduler_mutex); 544 if (uvm.scheduler_kicked == false) 545 cv_wait(&uvm.scheduler_cv, 546 &uvm_scheduler_mutex); 547 uvm.scheduler_kicked = false; 548 mutex_exit(&uvm_scheduler_mutex); 549 continue; 550 } 551 552 /* 553 * we have found swapped out process which we would like 554 * to bring back in. 555 * 556 * XXX: this part is really bogus cuz we could deadlock 557 * on memory despite our feeble check 558 */ 559 if (uvmexp.free > atop(USPACE)) { 560 #ifdef DEBUG 561 if (swapdebug & SDB_SWAPIN) 562 printf("swapin: pid %d(%s)@%p, pri %d " 563 "free %d\n", l->l_proc->p_pid, 564 l->l_proc->p_comm, l->l_addr, ppri, 565 uvmexp.free); 566 #endif 567 mutex_enter(&l->l_swaplock); 568 mutex_exit(proc_lock); 569 uvm_swapin(l); 570 mutex_exit(&l->l_swaplock); 571 continue; 572 } else { 573 /* 574 * not enough memory, jab the pageout daemon and 575 * wait til the coast is clear 576 */ 577 mutex_exit(proc_lock); 578 #ifdef DEBUG 579 if (swapdebug & SDB_FOLLOW) 580 printf("%s: no room for pid %d(%s)," 581 " free %d\n", __func__, l->l_proc->p_pid, 582 l->l_proc->p_comm, uvmexp.free); 583 #endif 584 uvm_wait("schedpwait"); 585 #ifdef DEBUG 586 if (swapdebug & SDB_FOLLOW) 587 printf("%s: room again, free %d\n", __func__, 588 uvmexp.free); 589 #endif 590 } 591 } 592 } 593 594 /* 595 * swappable: is LWP "l" swappable? 596 */ 597 598 static bool 599 swappable(struct lwp *l) 600 { 601 602 if ((l->l_flag & (LW_INMEM|LW_SYSTEM|LW_WEXIT)) != LW_INMEM) 603 return false; 604 if ((l->l_pflag & LP_RUNNING) != 0) 605 return false; 606 if (l->l_holdcnt != 0) 607 return false; 608 if (l->l_class != SCHED_OTHER) 609 return false; 610 if (l->l_syncobj == &rw_syncobj || l->l_syncobj == &mutex_syncobj) 611 return false; 612 if (l->l_proc->p_stat != SACTIVE && l->l_proc->p_stat != SSTOP) 613 return false; 614 return true; 615 } 616 617 /* 618 * swapout_threads: find threads that can be swapped and unwire their 619 * u-areas. 620 * 621 * - called by the pagedaemon 622 * - try and swap at least one processs 623 * - processes that are sleeping or stopped for maxslp or more seconds 624 * are swapped... otherwise the longest-sleeping or stopped process 625 * is swapped, otherwise the longest resident process... 626 */ 627 628 void 629 uvm_swapout_threads(void) 630 { 631 struct lwp *l; 632 struct lwp *outl, *outl2; 633 int outpri, outpri2; 634 int didswap = 0; 635 extern int maxslp; 636 bool gotit; 637 638 /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */ 639 640 #ifdef DEBUG 641 if (!enableswap) 642 return; 643 #endif 644 645 /* 646 * outl/outpri : stop/sleep thread with largest sleeptime < maxslp 647 * outl2/outpri2: the longest resident thread (its swap time) 648 */ 649 outl = outl2 = NULL; 650 outpri = outpri2 = 0; 651 652 restart: 653 mutex_enter(proc_lock); 654 LIST_FOREACH(l, &alllwp, l_list) { 655 KASSERT(l->l_proc != NULL); 656 if (!mutex_tryenter(&l->l_swaplock)) 657 continue; 658 if (!swappable(l)) { 659 mutex_exit(&l->l_swaplock); 660 continue; 661 } 662 switch (l->l_stat) { 663 case LSONPROC: 664 break; 665 666 case LSRUN: 667 if (l->l_swtime > outpri2) { 668 outl2 = l; 669 outpri2 = l->l_swtime; 670 } 671 break; 672 673 case LSSLEEP: 674 case LSSTOP: 675 if (l->l_slptime >= maxslp) { 676 mutex_exit(proc_lock); 677 uvm_swapout(l); 678 /* 679 * Locking in the wrong direction - 680 * try to prevent the LWP from exiting. 681 */ 682 gotit = mutex_tryenter(proc_lock); 683 mutex_exit(&l->l_swaplock); 684 didswap++; 685 if (!gotit) 686 goto restart; 687 continue; 688 } else if (l->l_slptime > outpri) { 689 outl = l; 690 outpri = l->l_slptime; 691 } 692 break; 693 } 694 mutex_exit(&l->l_swaplock); 695 } 696 697 /* 698 * If we didn't get rid of any real duds, toss out the next most 699 * likely sleeping/stopped or running candidate. We only do this 700 * if we are real low on memory since we don't gain much by doing 701 * it (USPACE bytes). 702 */ 703 if (didswap == 0 && uvmexp.free <= atop(round_page(USPACE))) { 704 if ((l = outl) == NULL) 705 l = outl2; 706 #ifdef DEBUG 707 if (swapdebug & SDB_SWAPOUT) 708 printf("%s: no duds, try procp %p\n", __func__, l); 709 #endif 710 if (l) { 711 mutex_enter(&l->l_swaplock); 712 mutex_exit(proc_lock); 713 if (swappable(l)) 714 uvm_swapout(l); 715 mutex_exit(&l->l_swaplock); 716 return; 717 } 718 } 719 720 mutex_exit(proc_lock); 721 } 722 723 /* 724 * uvm_swapout: swap out lwp "l" 725 * 726 * - currently "swapout" means "unwire U-area" and "pmap_collect()" 727 * the pmap. 728 * - must be called with l->l_swaplock held. 729 * - XXXCDC: should deactivate all process' private anonymous memory 730 */ 731 732 static void 733 uvm_swapout(struct lwp *l) 734 { 735 struct vm_map *map; 736 737 KASSERT(mutex_owned(&l->l_swaplock)); 738 739 #ifdef DEBUG 740 if (swapdebug & SDB_SWAPOUT) 741 printf("%s: lid %d.%d(%s)@%p, stat %x pri %d free %d\n", 742 __func__, l->l_proc->p_pid, l->l_lid, l->l_proc->p_comm, 743 l->l_addr, l->l_stat, l->l_slptime, uvmexp.free); 744 #endif 745 746 /* 747 * Mark it as (potentially) swapped out. 748 */ 749 lwp_lock(l); 750 if (!swappable(l)) { 751 KDASSERT(l->l_cpu != curcpu()); 752 lwp_unlock(l); 753 return; 754 } 755 l->l_flag &= ~LW_INMEM; 756 l->l_swtime = 0; 757 if (l->l_stat == LSRUN) 758 sched_dequeue(l); 759 lwp_unlock(l); 760 l->l_ru.ru_nswap++; 761 ++uvmexp.swapouts; 762 763 /* 764 * Do any machine-specific actions necessary before swapout. 765 * This can include saving floating point state, etc. 766 */ 767 cpu_swapout(l); 768 769 /* 770 * Unwire the to-be-swapped process's user struct and kernel stack. 771 */ 772 uarea_swapout(USER_TO_UAREA(l->l_addr)); 773 map = &l->l_proc->p_vmspace->vm_map; 774 if (vm_map_lock_try(map)) { 775 pmap_collect(vm_map_pmap(map)); 776 vm_map_unlock(map); 777 } 778 } 779 780 /* 781 * uvm_lwp_hold: prevent lwp "l" from being swapped out, and bring 782 * back into memory if it is currently swapped. 783 */ 784 785 void 786 uvm_lwp_hold(struct lwp *l) 787 { 788 789 if (l == curlwp) { 790 atomic_inc_uint(&l->l_holdcnt); 791 } else { 792 mutex_enter(&l->l_swaplock); 793 if (atomic_inc_uint_nv(&l->l_holdcnt) == 1 && 794 (l->l_flag & LW_INMEM) == 0) 795 uvm_swapin(l); 796 mutex_exit(&l->l_swaplock); 797 } 798 } 799 800 /* 801 * uvm_lwp_rele: release a hold on lwp "l". when the holdcount 802 * drops to zero, it's eligable to be swapped. 803 */ 804 805 void 806 uvm_lwp_rele(struct lwp *l) 807 { 808 809 KASSERT(l->l_holdcnt != 0); 810 811 atomic_dec_uint(&l->l_holdcnt); 812 } 813